Determination of Sugars in Tobacco by Ion Chromatography
Determination of Sugars in Tobacco by Ion Chromatography
Water-soluble sugars mainly refer to glucose, fructose and sucrose, which are common sugars in tobacco. And they play a very important role in both the quality of tobacco and tobacco products, as well as the flavor and taste of cigarettes.
In this paper, an ion chromatography is used to determine the content of water-soluble sugar. Experimenters use IC6300 ion chromatography with an ampere detector. eluent: NaOH and sodium acetate. simple pre-treatment, with good recovery and high sensitivity, this method is suitable for the determination of water-soluble sugars.
Keywords: tobacco products; sugars; ion chromatography
1. Experiment Section
1.1 Instruments and Reagents
Wayeal IC6300 Series Ion Chromatography
Ion chromatography: Wayeal IC6300 series ion chromatography with ampere detector (Au working electrode)
Auto sampler: AS2800
Sugar column: 250mm*4.0mm
D-(+) Glucose, anhydrous (99%);
Fructose (99%);
E-(+) Sucrose, AR;
Benzoic acid (99%);
Disposable syringe (2mL)
Water system syringe filter
One ten-thousandth electronic balance
Water is prepared by the ultrapure water purifier of Wayeal with a conductivity of 18.2 MΩ - cm (25 ℃).
1.2 Instrument Parameter
Sugar column: 250mm*4.0mm
Temperature: 30℃
Detector temperature: 35 ℃
Eluent: 250mM NaOH in A; 50mM NaOH in B; 1M sodium acetate in C; pure water in D; gradient eluting;
Flow rate: 0.3mL/min
Ampere detection pulse mode: Au electrode, sugars, quaternary potential
Injection volume: 25uL
1.3 Sample Pretreatment
Flue-cured tobacco: 0.1g sample (accurate to 0.1mg) in a 250mL conical flask, add 200mL 0.1% benzoic acid solution, put the lid on and place in an ultrasonic cell for 30min, then the solution is detected on a machine after passing through a 0.22μm filter membrane.
Cigar: 0.1g sample (accurate to 0.1mg) into a 250mL conical flask, add 50mL 0.1% benzoic acid solution, put the lid on and place in an ultrasonic cell for 30min, then the solution is detected on a machine after passing through a 0.22μm filter membrane.
2. Results and Discussion
2.1 Chromatogram
A series of standard working curves of 0.1mg/L, 0.5mg/L, 1.0mg/L, 2.0mg/L, 5.0mg/L, 10.0mg/L, and 20.0mg/L are pipetted respectively. Then the multipoint overlap standard curve spectra obtained according to 1.2 working conditions as shown in Figure 1. The linear correlation coefficients of glucose, sucrose and fructose under this condition are above 0.999 with good linearity.
Figure 1 Overlapping Chromatogram of Glucose, Sucrose and Fructose
Figure 2 Standard Curve of Glucose
Figure 3 Standard Curve of Sucrose
Figure 4 Standard Curve of Fructose
No
Compound
Linear Equation (math.)
Correlation Coefficient
1
Glucose
y=3044.02000x+431.15880
0.99941
2
Sucrose
y=896.97000x+88.82726
0.99933
3
Fructose
y=1723.92600x+174.80090
0.99941
2.2 Sample Result
Cigar and flue-cured tobacco samples are detected under the working conditions of 1.2. The sample chromatogram are shown as Figures 5 and 6. The target glucose, sucrose and fructose peaks in the sample chromatogram are symmetrical with good separation and non-interfering peaks.
Figure 5 Chromatogram of Cigar
Fig. 6 Chromatogram of Flue-cured Tobacco
Table 2. Sample Results
Samples
compound
Sample Test Content/%
Flue-cured Tobacco -1
Glucose
1.87
Sucrose
0.45
Fructose
1.73
Flue-cured Tobacco - 2
Glucose
1.93
Sucrose
0.44
Fructose
1.65
Cigar-1
Glucose
0.024
Sucrose
N.D.
Fructose
0.03
Cigar-2
Glucose
0.025
Sucrose
N.D.
Fructose
0.03
3.Conclusion
An ion chromatography method for the determination of sugar in tobacco products is established by using Wayeal 6300 series ion chromatography with an ampere detector. The samples were pre-treated and then separated by an ion chromatography column and quantified by external standard method, which is capable of qualitative and quantitative analysis of water-soluble sugars in the samples. The method is simple and easy to operate, with good repeatability, sensitivity and accuracy, which can be used for the determination of sugar content in tobacco products.
Determination of Six Conventional Cations in Wine by Ion Chromatography
Determination of Six Conventional Cations in Wine by Ion Chromatography
In this test, an ion chromatograph is used to test the six cations in wine. The method is simple, with good linearity and stable repeatability, and fully meets the testing requirements.
1. Experiment
1.1 Main Instruments and Reagents
Ion Chromatograph: IC6600 series with conductivity detector, cation suppressor, autosampler AS3110 series.
Chromatography Column: MS-5C-P2, 4.6*250mm, 5μm
Guard Column: MS-5CG, 4*30mm
Li+ Standard Solution (1000mg/L)
Na+ Standard Solution (1000mg/L)
NH4+ Standard Solution (1000mg/L)
K+ Standard Solution (1000mg/L)
Mg2+ Standard Solution (1000mg/L)
Ca2+ Standard Solution (1000mg/L)
Disposable Syringe (2mL)
Aqueous Microporous Filter Membrane(0.45μm)
Pretreatment Column: RP column
White Wine
Yellow Wine
Wine
1.2 Solution Preparation
1.2.1 Mixed Standard Solution
Pipette 0.1mL of Li+ standard solution (1000mg/L) into a 100mL volumetric flask, dilute and fix the volume with water, mix well; prepared to Li+ standard solution of 1.0 mg/L. Pipette 10mL of NH4+standard solution (1000mg/L), 10mL of Ca2+ standard solution (1000mg/L), 10mL of Mg2+ standard solution (1000mg/L) in one 100mL volumetric flask, dilute and fix the volume with water, mix well; prepared a standard solution containing 100mg/L of NH4+, 100mg/L of Mg2+, and 100mg/L of Ca2+ mixed standard solution.
1.2.2 Standard Working Solution
Pipette 0.1mL, 0.2mL, 0.5mL, 1mL, 2 mL, 5mL, 10mL, 20mL of Li+ standard solution (1.0mg/L), 0.05mL, 0.1mL, 0.2mL, 0.5mL, 1mL, 4mL, 10mL of NH4+, Mg2+, and Ca2+ mixed standard solution (100mg/L) respectively, 0.05mL, 0.1mL, 0.2mL, 0.5mL, 0.8mL, 1mL, 1.5mL, 2.0mL of Na2+ standard solution (1000mg/L), K+ standard solution (1000mg/L) 0.01mL, 0.05mL, 0.1mL, 0.2mL, 0.5mL, 1mL, 2mL, 5mL. Put in a set of 100mL volumetric flasks, diluted and fix the volume with water, mix well, and prepared into 8 different concentrations of the mixed standard series, the standard series of mass concentration is shown in Table 1.
Table 1 Concentration Gradient Table of Standard Curve
Concentration Gradient Table of Standard Curve
Compounds
Standard 1
Standard 2
Standard 3
Standard 4
Standard 5
Standard 6
Standard 7
Standard 8
Li+
0.001
0.002
0.005
0.01
0.02
0.05
0.1
0.2
Na+
0.5
1
2
5
8
10
15
20
NH4+
0.05
0.1
0.2
0.5
1
4
10
20
K+
0.1
0.5
1
2
5
10
20
40
Mg2+
0.05
0.1
0.2
0.5
1
4
10
20
Ca2+
0.05
0.1
0.2
0.5
1
4
10
20
1.3 Instrument Working Condition
Chromatography Column: MS-5C-P2, 4.6*250mm, 5μm
Guard Column: MS-5CG, 4*30mm
Temperature: 40°C
Conductivity Cell Temperature
Eluent: 22mM MSA
Flow Rate: 1.0mL/min
Suppressor Current: 66mA
Injection Volume: 25μL
1.4 Sample Pretreatment
A disposable syringe is used to aspirate the sample and pass it through the pre-treatment cartridge RP column and 0.45μm aqueous filtration membrane for the removal of organic matter in the sample, and 0.45μm aqueous filtration membrane for the removal of particulate matter in the sample.
2. Result and Discussion
2.1 Separation Verification
In 1.3 working conditions of the mixed standard solution, the standard chromatograms of 9 cations are shown in Fig. 1, and the test results are shown in Table 2. After testing, the peak shapes of the nine cations are symmetrical, and the separation of the components is good.
Fig 1 Chromatogram of 9 Ions Mixed Standard
Compounds
Retention Time
Peak Area
Concentration
(mg/L)
Separation
SNR
Li+
5.187
37.931
0.5
4.706
13499.755
Na+
6.230
45.849
2.0
2.607
14459.840
NH4+
6.937
57.247
2.5
2.879
13938.415
Methylamine
7.807
77.165
10
3.487
19271.353
K+
8.917
69.240
5.0
2.122
15502.730
Dimethylamine
9.680
60.338
10
6.530
11867.878
Trimethylamine
12.990
92.716
20
9.382
10502.103
Mg2+
20.733
103.154
2.5
5.505
7213.676
Ca2+
27.818
121.626
5.0
n.a.
5695.913
Table 2 Testing Result of 9 Ions Mixed Standard
2.2 Verification of Standard Curve Linearity
The working solution of the standard curve series prepared in 1.2.2 was injected into the system and analyzed according to the working conditions of 1.3, and the linearity of the standard curve was obtained as shown in Table 3 below, with good linearity.
Table 3 Linearity of Standard Curve
Compounds
Curvilinear Equation
Correlation Coefficient R
Li+
y=72.29391x-0.08781
0.99986
Na+
y=19.99226x+0.47697
0.99994
NH4+
y=0.25375x2+16.16416x+1.42735
0.99999
K+
y=13.36620x-0.31093
0.99999
Mg2+
y=37.96758x-2.36348
0.99996
Ca2+
y=23.39661x-1.85857
0.99986
2.3 Sample Testing
Samples of white wine, yellow wine and wine are tested according to 1.4 Sample pretreatment method, and the test spectra are shown in Fig. 3, Fig. 4 and Fig. 5, and the data are shown in Table 4 below.
Fig 3 White Wine Chromatogram of 6 Repeated Injections
Fig 4 6 Repeated Injections Chromatogram of Wine Diluted 20 Times
Fig 5 6 Repeated Injections Chromatogram of Yellow Wine Diluted 20 Times
Table 4 Test Data
Sample
Li+(mg/L)
Na+(mg/L)
NH4+(mg/L)
K+(mg/L)
Mg2+(mg/L)
Ca2+(mg/L)
White Wine
0.0019
2.44
0.576
0.128
0.191
0.627
Yellow Wine
0.0108
32.123
150.703
281.49
74.55
114.137
Wine
0.0097
43.727
11.314
694.748
51.575
47.377
Note: The relative standard deviations (RSDs) of the retention times and peak areas of the six cations were from 0.014% to 0.063% and 0.223% to 1.415%, respectively, and the spiked recoveries were in the range of 84.5%~108%.
3. Conclusion
The ion chromatography for the determination of six cations in wine shows good separation, good linearity, stable repeatability and high sensitivity. It can fully meet the requirements for the testing of the six cations in wine.
Troubleshooting of High Performance Liquid Chromatography (HPLC)
Troubleshooting of High Performance Liquid Chromatography (HPLC)
There are many test instruments used in the laboratory, and high-performance liquid chromatography (HPLC) is one of them. The instrument is based on classical chromatography, citing the theory of gas chromatography, and technically it changes the traditional mobile phase to high-pressure delivery. This article will give you the brief introduction of the chromatography, characteristics, failure causes, and treatment methods of high-performance liquid chromatography (HPLC).
Introduction of High-performance Liquid Chromatography
High performance liquid chromatograph (HPLC) is an instrument based on the principle of high performance liquid chromatography, which is mainly used to analyze less-volatile and thermal-unstable organic compounds with high boiling point and large molecular weight. It consists of solvent bottles, pump, sample injector, chromatographic column, detector, recorder and workstation.
How does high performance liquid chromatography work?
The mobile phase in the reservoir is pumped into the system by a high-pressure pump, and the sample solution passes through a sample injector then enters the mobile phase, which loads the sample solution into a chromatographic column (stationary phase). Because the various components in the sample solution have different distribution coefficients in the two phases, when they are moving relatively in the two phases, after repeated adsorption-desorption distribution processes, the moving speed of each component is greatly different, and the components are separated into single components flowing out of the column in turn. When passing through the detector, the sample concentration is converted into electrical signal and transmitted to the recorder, and the data is printed out in the form of chromatogram.
Applications of High-Performance Liquid Chromatography
HPLC is widely used in food, pharmaceutical, environment, agriculture and scientific research
1. Application in environmental analysis:
It can be used for the analysis of cyclic aromatic hydrocarbons (PAHs), pesticide residues, etc.
2. Application in food analysis:
It can be used for food nutrition analysis, food additive analysis, food contaminant analysis, etc.
3. Application in life science:
Purification, separation, and determination of molecular weight substances in life science, genetic engineering, clinical chemistry, molecular biology, and biochemistry can be studied at the molecular level.
4. Application in the medical examination: analysis and determination of metabolites in body fluids, pharmacokinetics, clinical drug monitoring, etc.
5. Application in inorganic analysis: analysis of anions and cations, etc.
Common Faults and Treatment Methods of High-Performance Liquid Chromatography
Fault Description
Cause Analysis
Solution
Front panel status indicator does not light up
Cable connection failure
Open the chassis and reconnect reliably
Switching power supply module cannot work and supply power
Replace the switching power module
Signal intensity too low
Bubbles are generated in the flow cell
Flush the flow cell and degasify the mobile phase
Prompt deuterium lamp failure
Deuterium lamp cannot be lit
Restart the instrument. If the fault cannot be eliminated, please replace the deuterium lamp.
Common troubleshooting of autosampler
Fault Description
Cause Analysis
Solution
Abnormal electrical initialization of the instrument
Software prompts: The zero-point optocoupler of the horizontal motor fails.
1. Restart the instrument
2. Check the sample chamber for any obstacles
3. Check the sensor at the corresponding position for any obvious abnormal phenomena such as looseness and line breakage
4. Call the after-sale service to solve the problem
Software prompts: The zero-point optocoupler of the vertical motor fails.
Software prompts: The zero-point optocoupler of the tray motor fails.
Software prompts: The zero-point optocoupler of the syringe motor fails.
Software prompts: EEPROM is unable to read or write.
1. Restart the instrument
2. Call the after-sale service to solve the problem
The software for the injection process indicated an exception
Software prompts: Sample vial is missing
1. Check whether the sample vial position is consistent with the software setting position
2. Restart the instrument
3. Call the after-sale service to solve the problem
Software prompts: The door is open
1. Check whether the door is normally closed
2. Check the door sensor for abnormalities
3. Restart the instrument
4. Call the after-sale service to solve the problem
Line fault
The status light on the front panel is not on
1. Restart the instrument
2. Check whether the power cord is reliably connected
3. Check whether the power switch is on
4. Check the fuse for damage
5. Call the after-sale service to solve the problem
The autosampler does not trigger the chromatogram
1. Check whether the trigger line is reliably connected
2. Check whether the instrument serial line is connected reliably
3. Check whether the software instrument networking light is flashing
Fluid line fault
There are obvious bubbles in the syringe during injection
1. Perform flushing fluid line process
2. Check whether the pipe joints are loose
3. Check joints for leakage
4. Too little liquid in the sample vial
There are small bubbles in the fluid line during injection
Poor reproducibility of sample injection
1. No ultrasonic processing to the sample
2. No ultrasonic processing to the wash solvent
3. There are obvious air bubbles in the pipeline syringe during injection
4. The sample vial was reused without cleaning
Common troubleshooting of pump
Fault Description
Cause Analysis
Solution
If the front panel status indicator is not light,
the connection may be loose,
Open the shell, and reconnect reliably.
Detection of power supply module
Replacement power supply module
Pump pressure is 0
pump head with air
Open purge valve, with syringe pumping, until there is liquid from the empty valve flow, and then tighten the valve.
Pressure alarm
pressure limit range setting unreasonable
According to the actual test needs, set a reasonable pressure limit range.
Pipeline blockage leads to excessive pressure.
Check whether the pipeline is gambling after pump head.
Leakage causes too little pressure
Check whether there is any damage to all levels of pipelines and streets after the pump head.
The buzzer keeps buzzing at a frequency of 0.5HZ.
Motor blocked, pressure upper limit alarm, pressure lower limit alarm, liquid leakage alarm.
Check and determine the cause of the error, and then solve it according to the situation
The buzzer beeps 3 times at a frequency of 1HZ and then stops
Leak sensor failure, pressure sensor failure, fan failure, photoelectric switch failure, solvent threshold alarm, unsuccessful initialization.
Check and determine the cause of the error, and then solve it according to the situation
Determination of Sugar Alcohol in Food by High Performance Liquid Chromatography
Determination of Sugar Alcohol in Food by High Performance Liquid Chromatography
1. Method and Principle
Determined by high performance liquid chromatography with an RID detector and quantified by external standard method.
2. Instrument Configuration and Experimental Methods
2.1 Instrument Configuration
No.
System Configurations
Qty
1
P3210B Binary High Pressure Gradient Pump
1
2
CT3210 Colum Oven
1
3
AS3210 Autosampler
1
4
RI Detector
1
5
4.6*250mm 5μm Amino Column
1
6
SmartLab Workstation
1
Table1 Configuration List
2.2 Experimental Method
2.2.1 Preparation of Reagents and Standards
No.
Reagents
Purity
1
Acetonitrile
Chromatographically pure
2
4 kinds of sweeteners mix standards
40g/L
Table 2 List of Reagents and Standards
Standard curve: The mixed standard (40 mg/mL) of the four sweeteners was diluted with water to a concentration of 1.6 mg/mL, 2.4 mg/mL, 3.2 mg/mL, 4.0 mg/mL, 4.8 mg/mL , 6.0 mg/mL series of concentration working curves.
2.22 Chromatography Conditions
Chromatography Column
Amino column， 4.6*250mm, 5μm
Mobile Phase
Acetonitrile ：Water=80：20
Flow Rate
1mL/min
Temperature
30°C
Cell Temperature
40°C
Injection Volume
20μL
Table 3 Chromatography Conditions
2.2.3 Sample Pretreatment
Samples of non-protein beverages should not be less than 200 mL and placed in an airtight container after being fully mixed. 10g of sample into a 50 mL volumetric flask, and fix the volume to 50 mL with water, shake well and detected on a machine after passing through a 0.22μm filter membrane.
3. Experimental Results
3.1 System Suitability
Figure 1 Chromatogram of 6.0mg/mLsweetener mixing standard
Notes: As the figure shows, there are good shape peaks of erythritol, xylitol, sorbitol and maltitol, and no other peaks around the target peaks, which meet the experimental requirements.
3.2 Linearity
Figure 2 Standard Curve of Erythritol
Figure 3 Standard Curve of Xylitol
Figure 4 Standard Curve of Sorbitol
Figure 5 Standard Curve of Maltose
The concentrations of mixing standard curves of the four sweeteners are 1.6 mg/mL, 2.4 mg/mL, 3.2 mg/mL, 4.0 mg/mL, 4.8 mg/mL, and 6.0 mg/mL. As the figure shows, the linear correlation coefficients of the standard curves of four sweeteners are above 0.999, which satisfied the experimental requirements.
3.3 Repeatability
Figure 6 Repeatability Chromatogram of 6 Injections of 3.2mg/mL Sweetener Mixing Standard
Retention Time
No.
Erythritol
Xylitol
Sorbitol
Maltitol
1
8.407
11.365
15.637
36.644
2
8.414
11.374
15.638
36.658
3
8.415
11.377
15.644
36.645
4
8.412
11.374
15.638
36.635
5
8.426
11.391
15.670
36.696
6
8.436
11.405
15.680
36.701
RSD(%)
0.128
0.128
0.120
0.077
Table 4 6 Injections of Retention Time Repeatability
Peak Area
No.
Erythritol
Xylitol
Sorbitol
Maltitol
1
228.976
239.243
234.601
224.837
2
230.029
238.083
239.130
224.900
3
224.656
237.784
236.914
222.373
4
227.415
239.595
238.192
222.414
5
227.455
240.591
238.963
223.679
6
228.492
239.876
237.412
227.865
RSD(%)
0.809
0.450
0.705
0.913
Table 5 6 Injections of Peak Area Repeatability
Note: As the table shows, the retention time RSD of erythritol, xylitol, sorbitol and maltitol are 0.128%, 0.128%, 0.120%, 0.077%, and the repeatability of retention time was less than 0.2%, which satisfied the experimental requirements. The peak area RSDs of erythritol, xylitol, sorbitol and maltitol are 0.809%, 0.450%, 0.705% and 0.913%. The repeatability of peak area was less than 1%, which satisfied the experimental requirements.
3.4 Detection Limit
Figure 7 Chromatogram of 1.6mg/mL Sweetener Mixing Standard
Note: As the Figure 7 shows, the concentration of 1.6 mg/mL sweetener mixing standard, the triple SNR is calculated from the detection limits of erythritol, xylitol, sorbitol, and maltitol are 0.01 mg/mL, 0.012 mg/mL, 0.015 mg/mL, and 0.03 mg/mL, which meet the experimental requirements.
3.5 A branded Non-protein Beverage
Figure 8 Chromatogram of a Branded Beverage in 2 Injections
Samples
Peak Area
Sample-1
209.594
Sample-2
209.001
Arithmetic Mean Value
209.298
Table 6 2 Injections for a Branded Beverage
As the chromatogram shows, erythritol is detected in a branded beverage and xylitol, sorbitol and maltitol are not detected. The test results are consistent with the ingredient list. The data in the table are the results of two tests with an absolute difference of 0.14% of the arithmetic mean, which is less than 10% of the standard requirement.
3.6 Attentions
Since the differential refractive index detector is sensitive to the density of the solution, it is recommended that the mobile phase be premixed when doing the experiment.
4 Conclusion
The analytical method introduced in this article refers to the national standard GB 5009.279-2016 (Determination of xylitol, sorbitol, maltitol and erythritol in food), by using a Wayeal LC3200 series high performance liquid chromatograph with a RID detector. The experimental results showed that the system adaptive testing of erythritol, xylitol, sorbitol and maltitol, the peaks are good and there are no other peaks around the target peaks. The RSDs for retention time are 0.128%, 0.128%, 0.120%, and 0.077%, all less than 0.2%. The RSDs of peak area are 0.809%, 0.450%, 0.705%, 0.913% and less than 1%. SNR=3 as detection limit, then detection limits of erythritol, xylitol, sorbitol, and maltitol are 0.01 mg/mL, 0.012 mg/mL, 0.015 mg/mL, and 0.03 mg/mL. The absolute difference between the two measurements is 0.14% of the arithmetic mean, which is less than 10% of the standard requirement. All the above data shows that the results satisfy the experimental requirements.
Determination of Tyrosol in Wine by High Performance Liquid Chromatography
Determination of Tyrosol in Wine by High Performance Liquid Chromatography
1. Instrument Configuration and Experiment Methods
1.1 Instrument Configuration
Table 1 Configuration List of Liquid Chromatography
No
Module
Qty
1
P3210B Binary Pump System
1
2
CT3400 Column Oven
1
3
AS3210 Autosampler
1
4
UV 3210 UV Detector
1
5
C18 Column, 4.6*250mm 5μm
1
6
SmartLab Workstation
1
1.2 Experiment Method
1.2.1 Reagent Preparation
No
Reagents
Purity
1
Methanol
Chromatographic Grade
2
Tyrosol Standard
98%
1.2.1.1 Tyrosol standard stock solution (1000mg/L): Take the appropriate amount of tyrosol standard, dissolve and Fix the volume with methanol, a standard stock solution with a concentration of 1000mg/L will be prepared, sealed and stocked at -4℃.
1.2.1.2 Tyrosol standard working solution: Pipette the appropriate amount of tyrosol standard stock solution accurately, dilute with methanol to form a series of working curves with concentrations of 0.1mg/L, 1mg/L, 1.5mg/L, 3mg/L, 5mg/L, 7.5mg/L, 10mg/L respectively.
1.2.2 Chromatography Conditions
Table 3 Chromatography Conditions
Chromatography Column
C18 Column 4.6*150mm, 5μm
Mobile Phase
A: Methanol, B: Water
Flow Rate
1mL/min
Column Temperature
40°C
Wavelength
222nm
Injection Volume
10μL
Table 4 Proportion of Mobile Phase
Time/min
A
B
0
30
70
9
35
65
9.1
100
0
12
100
0
13
30
70
20
30
70
1.2.3 Sample Pretreatment
Take appropriate amount of white wine samples, through the 0.45μm microporous filter membrane, then to be measured.
2. Experimental Result
2.1 System Suitability
Fig 1 Chromatogram of 10mg/L Standard
Table 5 10mg/L Standard Test Data
Compounds
Retention Time
Peak Height
Peak Area
Theoretical Plate Number
Tyrosol
7.209
29.398
367.785
7558
Note: From the chromatogram and data, it can be seen that the tyrosol peak shape is good, there are no other peaks around the target peak, and the theoretical plate number is high, which meets the experimental requirements.
2.2 Standard Curve
Fig 2 Test Result of Standard Curve
Note: From the above chromatogram, it can be seen that the correlation coefficient value R of tyrosol curve is above 0.999, which meets the experimental requirements.
2.3 Repeatability
Fig 3 Repeatability Chromatogram of 3.75mg/L Standard for 6 Injections
Table 6 Repeatability Test Data of 6 injections for 7.5mg/L Standard
Tyrosol
No.
Retention Time
Peak Area
1
7.205
284.108
2
7.209
286.256
3
7.210
285.346
4
7.216
285.676
5
7.212
286.806
6
7.207
288.199
RSD (%)
0.053
0.485
Note: According to the above table data, it can be seen that the RSD of tyrosol retention time repeatability is 0.053% and the RSD of peak area repeatability is 0.485%, both of which has good repeatability. It meets the experimental requirements.
2.4 Detection Limit
Fig 4 Test Chromatogram of 0.1mg/L Standard
Table 7 Test Data of 0.1mg/L Standard
Compound
Retention Time
Peak Area
SNR
Tyrosol
7.210
4.852
41.562
Note: According to the above table data, the detection limit of tyrosol is 0.0073mg/L with 3 times signal-to-noise ratio, which meets the experimental requirements.
2.5 Test Results of a Brand of White Wine
Fig 5 Test Chromatogram of a Brand White Wine
Table 8 Test Data of a Brand White Wine
Compound
Retention Time
Peak Area
Sample Volume
Tyrosol
7.210
4.852
0.275mg/L
Note: 0.275 mg/L of tyrosol was detected in a brand of white wine.
2.6 Spiked Testing Result of a Brand White Wine
Fig 6 Spiked Testing Chromatogram of a Brand White Wine
Table 9 Spiked Test Data of a Brand White Wine
Compounds
Retention Time
Peak Area
Sample Volume
Tyrosol
7.234
71.425
1.799mg/L
Note: Add 15μL of 100mg/L standard in a 1mL white wine, and according to the detection concentration of white wine and the spiked concentration, the theoretical concentration is 1.775 mg/L. From the detection concentration in the above table, the spiked recovery is 101.4%, which meets the experimental requirements.
2.7 Attentions
The Tyrosol Standard stock solution needs to be stored at low temperature, otherwise its content will decrease.
3. Conclusion
This article introduces the determination of tyrosol content in white wine by Wayeal high performance liquid chromatograph LC3210 series equipped with ultraviolet detector. The experimental results showed that the peak shape of tyrosol is good in the system adaptability test, and there are no other peaks around the target peak, and the theoretical plate number is high, which met the experimental requirements. The curve correlation coefficient R value is above 0.999. The RSD of tyrosol retention time is 0.053%, and the RSD of peak area is 0.485%, which is good reproducibility. The detection limit of tyrosol is 0.0073mg/L. The recoveries are 101.4% with the spiked 1.5mg/L in the sample. The results of the above data meet the requirements of the instrument for the test method.
Determination the Content of Acyclovir by High Performance Liquid Chromatography
Determination the Content of Acyclovir by High Performance Liquid Chromatography
The analytical method introduced in this article, with reference to the 2020 edition of the Pharmacopoeia of the People's Republic of China in Acyclovir test method, by using Wayeal high performance liquid chromatograph LC3200 series with a DAD detector.
1. Instrument Configuration and Experiment Method
1.1 Instrument Configuration
No
Name
Qty
1
P3210Q Quaternary Pump
1
2
CT3400 Column Oven
1
3
AS3210 Autosampler
1
4
DAD3260 DAD Detector
1
5
Nova Atom PC18 4.6x250mm 5μm
1
6
Chromatography Workstation
1
1.2 Experiment Method
1.2.1 Reagents Preparation
Table 2 List of Reagents
No
Reagents
Purity
1
2
3
4
5
Methanol
Phosphoric acid
Sodium hydroxide
Acyclovir
Guanine
Chromatographic Purity(LC)
GR
MOS
98%
99%
1.2.1.1 Test solution: Take 40mg of sample into a 200mL measuring flask, add 2mL of 0.4% sodium hydroxide to dissolve it, then add 25mL of 0.1% (V/V) phosphoric acid solution and dilute it with water to the scale, shake well.
1.2.1.2 Reference solution: Take 1mL of the test solution into a 100mL measuring flask, add 5mL of 0.1% phosphoric acid solution, dilute with water to scale and shake well.
1.2.1.3 Guanine control storage solution: Take 10mg of guanine reference into a 50mL measuring flask, add 5mL of 0.4% sodium hydroxide solution to dissolve it, then add 5mL of 0.1% phosphoric acid solution, dilute it with water to the scale, shake well.
1.2.1.4 Guanine reference solution: Take 1mL of guanine reference storage solution into a 100mL flask, dilute with water and shake well.
1.2.1.5 System suitability solution: Take appropriate amount of each of the reference solution and guanine reference solution, mix in equal volume and shake well.
1.2.2 Chromatography Condition
Table 3 Chromatography Conditions
Chromatography Column
Nova Atom PC18 Chromatography Column, 4.6*250mm, 5μm
Mobile Phase
Mobile Phase A: Water
Mobile Phase B: Methanol
Flow Rate
1mL/min
Column Temperature
35°C
Wavelength
254nm
Injection Volume
20μL
Table 4 Mobile Phase Ratio
Time (min)
Mobile Phase A
Mobile Phase B
0
94
6
15
94
6
40
65
35
41
94
6
51
94
6
2. Experiment Result
2.1 System Suitability Solution
Fig 1 Test Chromatogram of System Suitability Solution
Table 5 Test Data System Suitability Solution
No
Compound
Retention Time
Peak Area
Theoretical plate number
Separation
1
Guanine
5.698
138.675
17173
12.334
2
Acyclovir
8.425
139.902
15786
n.a.
Note: From the above graph and the data in the table, it can be seen that Acyclovir and Guanine have better peak shapes and high theoretical plate number. The degree of separation is more than 3.0, which meets the requirements in pharmacopoeia.
2.2 Repeatability
Fig 2 Repeatability Chromatogram of 6 Injections of System Suitability
Table 6 Repeatability Data of 6 Injections of System Suitability Solution Retention Time
Sample
No
Guanine
Acyclovir
Retention Time
1
5.698
8.408
2
5.701
8.415
3
5.705
8.411
4
5.701
8.405
5
5.705
8.401
6
5.705
8.398
RSD (%)
0.048
0.074
Table 7 Repeatability Data of 6 Injections of System Suitability Solution Peak Area
Sample
No
Guanine
Acyclovir
Peak Area
1
136.997
138.836
2
138.496
139.117
3
137.783
139.505
4
136.663
138.204
5
137.755
137.968
6
137.789
139.374
RSD (%)
0.475
0.452
Note: According to the data in the above table, the RSD of retention time of guanine and acyclovir in the system suitability solution is 0.048% and 0.074%, and the RSD of peak area is 0.475% and 0.452%, respectively. The reproducibility results are good and meet the experimental requirements.
Application of Ion Chromatography in Environmental Analysis
Application of Ion Chromatography in Environmental Analysis
Application of Ion Chromtography in Environmental Water Quality
With the development of social economy, water pollution has become an increasingly serious problem. In order to protect the environment and prevent water pollution, it is necessary to monitor rivers, lakes, seas and groundwater. For the treatment, recycling, comprehensive use and discharge of industrial and domestic wastewater, water quality analysis is required first. In the process of analysis, ion chromatography can be applied. The ion chromatography is widely used in water quality analysis because of its high efficiency, stability and accuracy.
Water Quality——Inorganic Anion Analysis
Determination of Acetic Acid and Sulfate Ions in Hydroxyethyl Cellulose by Ion Chromatography
Determination of Acetic Acid and Sulfate Ions in Hydroxyethyl Cellulose by Ion Chromatography
1. Experiment Method
1.1 Test Conditions
Instrument: Ion chromatograph IC6200 series with conductivity detector
Chromatography Column: NovaChrom HS-5A-P3 (4.0mm*250mm)
Guard Column: NovaChrom HS-5AG (4.0mm*30mm)
Eluent: 18mM KOH
Column Temperature: 30°C
Flow Rate: 1.0ml/min
Injection Volume: 25μL
Suppressor: anions suppressor
1.2 Experiment Reagents
Acetic acid standards: 1000mg/L
Sulfate ion standards: 1000mg/L
Hydroxyethyl cellulose sample
1.3 Standards Preparation
Pipette 0.1mL, 0.2mL, 0.5mL, 0.8mL, 1.0mL, 1.5mL acetic acid standard solution (1000 mg/L), 0.2mL, 0.5mL, 0.8mL, 1.0mL, 1.5mL, 2.0mL sulfate ion standard solution (1000 mg/L) in a set of 100mL volumetric flasks respectively, and fix the volume with ultrapure water, and mixed well.
1.4 Sample Preparation
Take a certain amount of hydroxyethyl cellulose to 100mL volumetric flask and fix the volume with ultrapure water, let stand for an hour until the sample is completely dissolved, diluted through the C18 column, the filter membrane and test.
2. Test Result
2.1 Linear Testing
2.1.1 Linear test for acetic acid and sulfate ions
The concentrations of the standard curve series are shown in Table 1. Testing according to the test conditions of 1.1, and the multi-point overlap chromatogram of standard curves as shown in Figure 1.
Table 1 Concentration Gradient Table of Standard Curve
Table 1 Concentration Gradient Table of Standard Curve (mg/L)
Compound
Standard Curve 1
Standard Curve 2
Standard Curve 3
Standard Curve 4
Standard Curve 5
Standard Curve 6
Acetic Acid
1
2
5
8
10
15
SO42-
2
5
8
10
15
20
Fig 1 Multi-point Overlap Chromatogram of Standard Curves
Table 2 Linear Equations of Acetic Acid and Sulfate Ion
No.
Ions
Linear Equations
Correlation Coefficient R
1
Acetic Acid
y=6.20870x+3.53190
0.99957
2
SO42-
y=15.38419x-8.82943
0.99967
2.2 Sample Repeatability Testing
According to the chromatographic conditions of “1.1”, six consecutive injections of samples were analyzed, and the chromatogram are shown in Figure 2. There are no other peaks around the acetic acid and sulfate ions and the peaks were well separated. Their repeatability data are shown in Table 3. The retention time RSD of acetic acid is 0.046% and peak area RSD is 0.293%. The retention time RSD of sulfate ion is 0.219%, and peak area RSD is 0.542%. The repeatability is good.
Fig 2 Overlap Chromatogram of 6 Injections
Table 3 Repeatability Data of 6 Injections
Samples
Retention Time
Peak Area
Samples
Retention Time
Peak Area
Acetic Acid in Sample
4.431
54.35
SO42- in Sample
20.953
106.848
4.434
54.677
21.029
107.236
4.431
54.821
20.962
108.278
4.430
54.729
20.931
107.285
4.429
54.685
20.912
107.38
4.428
54.644
20.903
108.244
Average
4.431
54.651
Average
20.948
107.545
RSD%
0.046
0.293
RSD%
0.219
0.542
3. Conclusion
The established ion chromatography method for the detection of acetic acid and sulfate ions in hydroxyethyl cellulose showed good separation and stable reproducibility, which fully meets the needs of ion chromatography for the determination of acetic acid and sulfate ions.
Determination of 6-methylcoumarin in Cosmetics by Liquid Chromatography
Determination of 6-methylcoumarin in Cosmetics by Liquid Chromatography
1.1 Instrument Configuration
Table 1 Configuration List of Liquid Chromatography
No.
Module
Qty
1
PB3210 Binary Pump
1
2
CT3400 Column Oven
1
3
AS3210 Autosampler
1
4
UV3210 UV Detector
1
5
NovaChrom SC18 4.6*250mm, 5μm
1
6
SmartLab Workstation
1
1.2 Experiment Method
1.2.1 Reagents
Table 2 List of Reagents
No.
Reagents
Purity
1
Methanol
Chromatographic Grade
2
6-methylcoumarin
99%
3
Ammonium dihydrogen phosphate
AR
4
Phosphoric acid
GR
1.2.1.1 6-Methylcoumarin standard stock solution (1000mg/L): Take appropriate amount of 6-methylcoumarin standard, dissolved and fix the volume with methanol and prepared into a concentration of 1000mg/L standard stock solution.
1.2.1.2 6-Methylcoumarin standard working solution: Pipette appropriate amount of 6-methylcoumarin standard stock solution and diluted with methanol to prepared a series of working curves with concentrations of 0.1mg/L, 0.5mg/L, 1.0mg/L, 3.0mg/L, 5.0mg/L and 10.0mg/L respectively.
1.2.1.3 Sodium dihydrogen phosphate buffer solution: Take 3.12g of sodium dihydrogen phosphate, add water to dissolve and dilute to 1000mL, and adjust the pH of phosphoric acid to 3.5.
1.2.2 Chromatography Conditions
Table 3 Chromatography Conditions
Chromatography Column
NovaChrom SC18 4.6*250mm 5μm
Mobile Phase
A: Methanol，B：Sodium dihydrogen phosphate buffer solution
Flow Rate
1mL/min
Column Temperature
35°C
Wavelength
275nm
Injection Volume
10μL
Table 4 Gradient Elution Program
Time(min)
Mobile Phase A
Mobile Phase B
0
55
45
11
55
45
12
90
10
40
90
10
41
55
45
50
55
45
1.2.3 Sample Pretreatment
Take 1g (accurate to 0.001g) of the sample in a 10mL volumetric flask, add 5mL of methanol, vortexing and shaking to fully mix the sample with the extraction solution, ultrasonic extraction for 20min, cooled to room temperature, and then fix the volume to 10mL with methanol, mixing and then transferring to centrifugal tubes, centrifuged at 5000r/min for 5min, and the supernatant filtered through the 0.45µm organic membrane, and then to be tested.
2. Experiment Result
2.1 System Suitability
Fig 1 10mg/L Chromatogram of Standards
Table 5 Test Data of 10mg/L Standards
Compounds
Retention Time
Peak Area
Theoretical Plate Number
6-methylcoumarin
11.168
574.285
15854
Note：The chromatogram and data show that 6-methylcoumarin has a good peak shape, and there are no other peaks around the target peak, and the theoretical plate number is high, which meets the experimental requirements.
2.2 Standard Curve
Fig 2 Test Result of Standard Curve
Note: The chromatogram shows that the R value of the correlation coefficient of the 6-methylcoumarin curve is above 0.9999, which meets the experimental requirements.
2.3 Repeatability
Fig 3 Repeatability Chromatogram of 3mg/L Standards of 6 Injections
Table 6 Repeatability Data of 3mg/L Standards of 6 InjectionsTable 6 Repeatability Data of 3mg/L Standards of 6 Injections
6-methylcoumarin
No.
Retention Time
Peak Area
1
11.159
177.710
2
11.161
176.711
3
11.142
177.128
4
11.152
176.985
5
11.150
177.469
6
11.149
177.629
RSD(%)
0.061
0.222
Note: According to the data in the above table, the RSD of retention time repeatability of 6-methylcoumarin is 0.061%, and the RSD of peak area repeatability is 0.222%. The repeatability is good and meet the experimental requirements.
2.4 Detection Limit
Fig 4 Test Chromatogram of 0.02mg/L Standards
Table 7 Test Data of 0.02mg/L Standards
Compounds
Retention Time
Peak Area
SNR
6-methylcoumarin
11.153
1.208
19.296
Note: According to the above data, 3 times signal-to-noise ratio is calculated as the detection limit, and it was found that the detection limit of 6-methylcoumarin is 0.004mg/L. It meets the experimental requirements.
2.5 Test Result of a Cosmetic Sample
Fig 5 Test Chromatogram of a Cosmetic Sample
Note: 6-Methylcoumarin was not detected in a cosmetic sample.
2.6 Attention
When using a high-speed centrifuge, take care that the tubes are symmetrically placed and the total mass of the tubes on opposite sides is the same.
3. Conclusion
The analytical method introduced in this article, with reference to the “Safety and Technical Standards for Cosmetics” in the detection of 6-methylcoumarin, by using Wayeal high performance liquid chromatography LC3200 series with UV detector. The experiment result shows that the peak shape of 6-methylcoumarin is good in the system adaptability test, and there are no other peaks around the target peak, and the theoretical plate number is high, which meets the experimental requirements. The curve correlation coefficient R value is above 0.9999. The RSD of retention time repeatability of 6-methylcoumarin is 0.061%, and the RSD of peak area repeatability is 0.222%, which shows good repeatability. The detection limit of 6-methylcoumarin is 0.004mg/L. All the above test results meet the requirements of the instrument in the standard method.
Determination of Lead in White Wine by Atomic Absorption Spectrophotometry
Determination of Lead in White Wine by Atomic Absorption Spectrophotometry
In this paper, an analytical method is developed for the determination of lead elemental content in white wine by atomic absorption spectrophotometry. Lead showed good linearity in the concentration range of 1.0-40μg/L with linear correlation coefficients greater than 0.999. The RSD range for three injections is within 1.5%. The sample spiking recovery is 95.4%. The method is accurate, reliable and sensitive for the determination of lead in white wine.
Keywords: Atomic absorption, autosampler, white wine, lead
1. Experiment Method
1.1 Instrument Configuration
Table 1 Configuration List of Atomic Absorption Spectrophotometer
No.
Modular
Qty
1
Atomic Absorption Spectrophotometer AA2310
1
2
Graphite Furnace Power
1
3
Autosampler
1
4
Cooling Water Circulator
1
5
High Purity Argon
1
1.2 Test Conditions
Wavelength: 283.3nm
Spectral Bandwidths: 0.4nm
Lamp Current: 5mA
Ignite: AA-BG
Injection Volume: 20μL
Temperature Program
No.
Temperature (°C)
Time (s)
Heating Method
Sensitivity
Gases
Gas Circuit
1
100
10
RAMP
Low
Argon
0.2
2
130
20
RAMP
Low
Argon
0.2
3
400
15
RAMP
Low
Argon
1.0
4
400
10
RAMP
Low
Argon
1.0
5
400
3
RAMP
Low
Argon
0.0
6
1900
3
STEP
Low
Argon
0.0
7
2100
2
STEP
Low
Argon
1.0
1.3 Reagents and Experiment Material
1.3.1 Nitric acid solution (1+99): Take 10mL of nitric acid and slowly add to 990mL of water and mix well.
1.3.2 Nitric acid solution (1+9): Take 50mL of nitric acid and slowly add to 450mL of water, and mix well.
1.3.3 Lead standard solution: 1000mg/L
1.3.4 One in ten thousand analytical balances
1.3.5 Digital display electric hot plate
1.3.6 Constant temperature drying oven
1.4 Sample Preparation
1.4.1 Lead standard intermediate solution
Pipette 0.1mL into 100mL volumetric flask, and fix the volume with 1% nitric acid, shaking well, prepared a concentration of 1mg/L of lead standard intermediate solution. Store under refrigeration at 0℃-4℃. Dilute with 1% nitric acid before use.
1.4.2 Lead Standard Working Solution
Pipette 400μL of lead standard intermediate solution in a 10mL volumetric flask, and fix the volume with 1% nitric acid, prepared a concentration of 40μg/L of lead standard solution, Prepare it when it will be used.
1.5 Sample Pre-treatment
Wet Digestion
Take 5.0mL of the liquid sample in a polytetrafluoroethylene crucible. The ethanol-containing samples are heated on a hot plate at a low temperature of 120°C to remove the ethanol firstly. Add 10mL of nitric acid and 0.5mL of perchloric acid, cover, and dissolve on a digital hot plate. (Reference conditions: 120 ℃/0.5 h~1 h; up to 180 ℃/2 h~4 h, up to 200 ℃~220 ℃). Open the lid and digest until white smoke is emitted and the digestion solution is colorless and transparent, drive the acid to nearly dry, stop dissolving, cool down and then dilute to 25 mL with water, mix well and spare. A reagent blank test was also done.
2. Result and Discussion
2.1 Standard Curve
Take 40μg/L lead standard working solution, according to the test conditions of 1.2 for injection and analysis, the autosampler selects the automatic dilution. Take concentration as the horizontal coordinate and absorbance as the vertical coordinate, and the external standard method is used to establish the working curve. The result is as shown Fig 1. The curve equation of lead in the concentration range of 1.0-40μg/L is y=0.008348*x+0.063430 with an R value of 0.9995, which has good linearity and meets the experimental requirements.
Fig 1 Lead Standard Curve
2.2 RSD of Standard Sample
The RSD value of 3 repeated injection of the standard is within 1.5%, and the stability of the instrument is in accordance with the experimental standards.
Fig 2 Overlap Chromatogram of Standard 32μg/L with 3 Repeated Injections
Table 2 Absorbance Data of Standard 32μg/L with 3 Repeated Injections
Standard Point 5
Absorbance
Background Absorbance
RSD (%)
32μg/L
0.3779
0.0051
0.65
0.3762
0.0040
0.3731
0.0044
2.3 Sample Spiking Rate
The digestion samples and sample blanks as well as spiked samples are injected and analyzed according to the test conditions of 1.2, and the sample chromatogram are shown in Fig. 3 and the spiked sample chromatogram are shown in Fig. 4. The data shows that the sample was not detected and the recoveries of the spiked samples were 95.4%. It meets the experimental requirements.
Fig 3 Sample Chromatogram
Fig 4 Sample Chromatogram
3. Conclusion
The curve equation of lead in the concentration range of 1.0-40μg/L was y=0.008348*x+0.063430 with an R value of 0.9995, which had a good linearity in accordance with the experimental requirements. The RSD range for three repeated injections was within 1.5%. The sample spiking recovery was 95.4%. The method is accurate, reliable and sensitive for the determination of lead in white wine.
Determination of Lead in White Wine by Atomic Absorption Spectrophotometry
Determination of Lead in White Wine by Atomic Absorption Spectrophotometry
In this paper, an analytical method is developed for the determination of lead elemental content in white wine by atomic absorption spectrophotometry. Lead showed good linearity in the concentration range of 1.0-40μg/L with linear correlation coefficients greater than 0.999. The RSD range for three injections is within 1.5%. The sample spiking recovery is 95.4%. The method is accurate, reliable and sensitive for the determination of lead in white wine.
Keywords: Atomic absorption, autosampler, white wine, lead
1. Experiment Method
1.1 Instrument Configuration
Table 1 Configuration List of Atomic Absorption Spectrophotometer
No.
Modular
Qty
1
Atomic Absorption Spectrophotometer AA2310
1
2
Graphite Furnace Power
1
3
Autosampler
1
4
Cooling Water Circulator
1
5
High Purity Argon
1
1.2 Test Conditions
Wavelength: 283.3nm
Spectral Bandwidths: 0.4nm
Lamp Current: 5mA
Ignite: AA-BG
Injection Volume: 20μL
Temperature Program
No.
Temperature (°C)
Time (s)
Heating Method
Sensitivity
Gases
Gas Circuit
1
100
10
RAMP
Low
Argon
0.2
2
130
20
RAMP
Low
Argon
0.2
3
400
15
RAMP
Low
Argon
1.0
4
400
10
RAMP
Low
Argon
1.0
5
400
3
RAMP
Low
Argon
0.0
6
1900
3
STEP
Low
Argon
0.0
7
2100
2
STEP
Low
Argon
1.0
1.3 Reagents and Experiment Material
1.3.1 Nitric acid solution (1+99): Take 10mL of nitric acid and slowly add to 990mL of water and mix well.
1.3.2 Nitric acid solution (1+9): Take 50mL of nitric acid and slowly add to 450mL of water, and mix well.
1.3.3 Lead standard solution: 1000mg/L
1.3.4 One in ten thousand analytical balances
1.3.5 Digital display electric hot plate
1.3.6 Constant temperature drying oven
1.4 Sample Preparation
1.4.1 Lead standard intermediate solution
Pipette 0.1mL into 100mL volumetric flask, and fix the volume with 1% nitric acid, shaking well, prepared a concentration of 1mg/L of lead standard intermediate solution. Store under refrigeration at 0℃-4℃. Dilute with 1% nitric acid before use.
1.4.2 Lead Standard Working Solution
Pipette 400μL of lead standard intermediate solution in a 10mL volumetric flask, and fix the volume with 1% nitric acid, prepared a concentration of 40μg/L of lead standard solution, Prepare it when it will be used.
1.5 Sample Pre-treatment
Wet Digestion
Take 5.0mL of the liquid sample in a polytetrafluoroethylene crucible. The ethanol-containing samples are heated on a hot plate at a low temperature of 120°C to remove the ethanol firstly. Add 10mL of nitric acid and 0.5mL of perchloric acid, cover, and dissolve on a digital hot plate. (Reference conditions: 120 ℃/0.5 h~1 h; up to 180 ℃/2 h~4 h, up to 200 ℃~220 ℃). Open the lid and digest until white smoke is emitted and the digestion solution is colorless and transparent, drive the acid to nearly dry, stop dissolving, cool down and then dilute to 25 mL with water, mix well and spare. A reagent blank test was also done.
2. Result and Discussion
2.1 Standard Curve
Take 40μg/L lead standard working solution, according to the test conditions of 1.2 for injection and analysis, the autosampler selects the automatic dilution. Take concentration as the horizontal coordinate and absorbance as the vertical coordinate, and the external standard method is used to establish the working curve. The result is as shown Fig 1. The curve equation of lead in the concentration range of 1.0-40μg/L is y=0.008348*x+0.063430 with an R value of 0.9995, which has good linearity and meets the experimental requirements.
Fig 1 Lead Standard Curve
2.2 RSD of Standard Sample
The RSD value of 3 repeated injection of the standard is within 1.5%, and the stability of the instrument is in accordance with the experimental standards.
Fig 2 Overlap Chromatogram of Standard 32μg/L with 3 Repeated Injections
Table 2 Absorbance Data of Standard 32μg/L with 3 Repeated Injections
Standard Point 5
Absorbance
Background Absorbance
RSD (%)
32μg/L
0.3779
0.0051
0.65
0.3762
0.0040
0.3731
0.0044
2.3 Sample Spiking Rate
The digestion samples and sample blanks as well as spiked samples are injected and analyzed according to the test conditions of 1.2, and the sample chromatogram are shown in Fig. 3 and the spiked sample chromatogram are shown in Fig. 4. The data shows that the sample was not detected and the recoveries of the spiked samples were 95.4%. It meets the experimental requirements.
Fig 3 Sample Chromatogram
Fig 4 Sample Chromatogram
3. Conclusion
The curve equation of lead in the concentration range of 1.0-40μg/L was y=0.008348*x+0.063430 with an R value of 0.9995, which had a good linearity in accordance with the experimental requirements. The RSD range for three repeated injections was within 1.5%. The sample spiking recovery was 95.4%. The method is accurate, reliable and sensitive for the determination of lead in white wine.
Determination of Polyethylene Glycol by Gel Permeation Chromatography
Determination of Polyethylene Glycol by Gel Permeation Chromatography
1. Introduction
Purpose: Determination of molecular weight and distribution of polyethylene glycol (PEG) by high performance gel permeation chromatography (GPC) method.
Method:
Xtimate SEC-120, 5 μm, 7.8x300 mm gel permeation chromatography column
Differential refractive index detector (RID)
Mobile phase: ultrapure water
Flow rate: 1.0ml/min
Column temperature: 35 ℃;
Injection volume: 10μl.
Calibration curves are established and the molecular weight and distribution results of each sample are calculated by GPC software.
Result: The linearity of PEG is good when the molecular weight was in the range of 400-20000. The reproducibility of the experiment is good, with 6 consecutive injections of PEG6000, the RSD value of retention time is 0.105%, and the RSD value of peak area is 0.335%.
Conclusion: High performance gel permeation chromatography (GPC) is a reliable method for the determination of molecular weight and distribution of PEG, which has the advantages of accurate and high reproducibility when used to evaluate the polydispersity property of polymer compounds.
Keywords: HPLC, GPC, RID, Polymer, Polyethylene Glycol
2. Experiment Method
2.1 Instrument Configuration
Table 1 Configuration List of High Performance Liquid Chromatograph
No
Modular
Qty
1
High Performance Liquid Chromatography LC3200 Series
1
2
PB3200 Binary Pump
1
3
RID3300
1
4
CT3200 Column Oven
1
5
AS3200 Autosampler
1
2.2 Test Conditions
Chromatography Column: Xtimate SEC-120，5μm，7.8x300mm
Column Temperature: 35°C
Detector: RID
Flow Rate: 1.0mL/min
Mobile Phase: Water
Injection Volume: 10μL
2.3 Instrument/Reagents and Consumables
Reagents:
Ultrapure Water
Standard: PEG400; PEG2000; PEG6000; PEG10000; PEG20000
Auxiliary Equipment
Analytical Balances
Solvent Extraction Unit
Ultrasonic Cleaner
Experimental Materials
Filter Membrane: aqueous filter membrane 0.45μm
2.4 Preparation of PEG Standard
Pipette 0.20g each of PEG400, PEG2000, PEG6000, PEG10000 and PEG20000 standards, add 10mL of water to dissolve, mix well, and prepared the concentration of 20mg/mL samples to be tested.
3. Result and Discussion
3.1 Different Molecular Weight Standards
Fig 1 Chromatogram of PEG400
Table 1 Chromatographic Parameters of PEG400
No
Compounds
Retention Time
Peak Area
Theriacal Plate Number
Trailing Factor
1
PEG400
10.315
501.732
2346
1.185
Fig 2 Chromatogram of PEG2000
Table 2 Chromatographic Parameters of PEG2000
No
Compounds
Retention Time
Peak Area
Theoretical Plate Number
Trailing Factor
1
PEG2000
8.659
499.892
1926
1.230
Fig 3 Chromatogram of PEG6000
Table 3 Chromatographic Parameters of PEG6000
No
Compounds
Retention Time
Peak Area
Theoretical Plate Number
Trailing Factor
1
PEG6000
7.215
499.482
1.171
Fig 4 Chromatogram of PEG10000
Table 4 Chromatographic Parameters of PEG10000
No
Compounds
Retention Time
Peak Area
Theoretical Plate Number
Trailing Factor
1
PEG10000
6.612
483.657
2550
1.265
Fig 5 Chromatogram of PEG20000
Table 5 Chromatographic Parameters of PEG20000
No
Compounds
Retention Time
Peak Area
Theoretical Plate Number
Trailing Factor
1
PEG20000
6.081
497.803
1103
1.799
Fig 6 Overlap Chromatograms of Different Molecular Weight
Note: The above data shows that the retention time of PEG20000 is 6.081 minutes, and PEG400 is 10.315 minutes, larger molecules are eluted first and smaller molecules are eluted later.
3.2 Repeatability
Fig 7 Repeatability Overlap Chromatograms of PEG6000 (n=6)
Table 7 Repeatability Chromatographic Parameters of PEG6000 (n=6)
No
Samples
Retention Time
Peak Area
1
6000
7.233
498.821
2
6000
7.234
503.367
3
6000
7.225
499.891
4
6000
7.221
499.560
5
6000
7.219
501.374
6
6000
7.215
499.482
Average
-
7.225
500.416
RSD(%)
-
0.105
0.335
Note: The repeatability is good. The RSD of retention time is 0.105% and the RSD of peak area is 0.335% for 6 injections of PEG6000.
3.3 Standard Curves
Fig 8 Standard Curves Chromatograms of Different Molecular Weights
Table 8 Standard Curves Chromatographic Parameters of Different Molecular Weights
Note: The molecular weight and distribution results of each sample are calculated by GPC software. The linearity of PEGmolecular weight is good in the eange of 400 to 20,000, and the linear correlation coefficient is 0.999.
4. Conclusion
This polyethylene glycol (PEG) test is performed by gel chromatography by using an LC3200 series high performance liquid chromatograph with differential refractive index detector. the retention time of PEG20000 is 6.081 minutes, and PEG400 is 10.315 minutes, larger molecules are eluted first and smaller molecules are eluted later. The repeatability is good. The RSD of retention time is 0.105% and the RSD of peak area is 0.335% for 6 injections of PEG6000. The linearity of PEG molecular weight is good in the range of 400 to 20,000, and the linear correlation coefficient is 0.9999. High performance gel permeation chromatography (GPC) is a reliable method for the determination of molecular weight and distribution of PEG, which has the advantages of accurate and reproducible results when used to evaluate the polydispersity property of polymer compounds.
Note: The sample should be left at room temperature for more than 12h and should be mixed gently, do not ultrasonic or shake vigorously to accelerate dissolution.
Determination of Heavy Metals in Waste Resin Powder by Wayeal Atomic Absorption Spectrophotometer
Determination of Heavy Metals in Waste Resin Powder by Wayeal Atomic Absorption Spectrophotometer
In this paper, with reference to the standard of "HJ 749-2015 Determination of Total Chromium in Solid Waste Flame Atomic Absorption Spectrophotometry" "HJ 786-2016 Determination of Lead, Zinc and Cadmium in Solid Waste Flame Atomic Absorption Spectrophotometry", an analytical method was established for the determination of the content of heavy metal elements in waste resin powder by flame atomic absorption method.
Keywords: Atomic Absorption Spectrophotometer; flame, waste resin powder; lead; cadmium; chromium.
1. Experiment Method
1.1 Instrument Configuration
Table 1 Configuration List of Atomic Absorption Spectrophotometer
No
Name
Qty
1
Atomic Absorption Spectrophotometer AA2310
1
2
Air Compressor
1
3
High-purity Acetylene
1
4
Lead Hollow Cathode Lamp
1
5
Cadmium Hollow Cathode Lamp
1
6
Chromium Hollow Cathode Lamp
1
1.2 Reagents and Instruments
1.2.1 Lead Standard Solution(1000μg/ml)
1.2.2 Cadmium Standard Solution(1000μg/ml)
1.2.3 Chromium Standard Solution(1000μg/ml)
1.2.4 Ammonium Chloride: AR
1.2.5 Nitric Acid: GR
1.2.6 Hydrochloric Acid: GR
1.2.7 Hydrofluoric Acid: GR
1.2.8 Perchloric Acid: GR
1.2.9 30% Hydrogen Peroxide: GR
1.2.10 One in ten thousand analytical balances
1.2.11 Digital display electric hot plate
1.3 Pre-processing
1.3.1 Pre-processing of Lead and Cadmium Samples
Take 0.2g of sample (accurate to 0.1mg) into a 50ml PTFE crucible. After wetting with water, 5ml of hydrochloric acid was added and the sample was heated on a hot plate in a fume hood at about 120 ℃ to initially disintegrate the sample, and then removed and cooled slightly after evaporation until about 3m remained. Add 8ml of nitric acid, 8ml of hydrofluoric acid and 4ml of perchloric acid, cover and heat at about 160 ℃ on a hot plate for 3h. Open the lid, the electric heating plate temperature control at 180 ℃ to continue heating, and often shake the crucible. When heated to a thick white smoke, cover to fully decompose the black organic carbons. After the black organic matter on the crucible wall disappears, open the lid, drive away the white smoke and steam until the contents are viscous. Take down the crucible, slightly cold, add 0.2mL nitric acid to dissolve the soluble residue, after cooling, transfer the whole amount to 50ml volumetric flask, rinse the crucible lid and inner wall with appropriate amount of experimental water, the washing solution was incorporated into 50ml volumetric flask, and the fix the volume with experimental water, shaken well, and then left to be measure. If there are undissolved particles in the digested solution, filtering and centrifugation or natural precipitation are required. (Note: Do not allow a lot of bubbles to come out when heating, otherwise it will cause loss of the sample.)
1.3.2 Pre-processing of Chromium Sample
Take 0.2g (accurate to 0.0001g) of sample into a 50ml PTFE crucible. After wetting with water, 10ml of concentrated hydrochloric acid was added and the sample was heated on a hot plate in a fume hood at 50°C to initially decompose the sample. When evaporated to about 3ml, add 5ml of concentrated nitric acid, 5ml of hydrofluoric acid, cover and heat on the hot plate at about 120~130 ℃ for 0.5~1h, then open the lid, drive away the white smoke and steam until the contents are in the form of liquid beads in a non-flowing state (observe while hot). Depending on the condition of digestion, add 3ml of concentrated nitric acid, 3ml of hydrofluoric acid, 1ml of hydrogen peroxide, and repeat the above digestion process. Take down the crucible, slightly cold, add 0.2mL nitric acid to dissolve the soluble residue, transfer all the test solutions to a 50ml volumetric flask, add 5ml of 110% ammonium chloride solution, and fix the volume with experimental water, left to be measured. (Note: the total amount of 30% hydrogen peroxide added shall not exceed 10ml.)
2. Results and Discussion
Lead
Detection Sample
Lead
Burner Hight
10mm
Acetylene Flow Rate
2.0L/min
Spectral Bandwidth
0.4nm
Wavelength
283.3nm
Lighting Way
AA
Lamp Current
5mA
Gradient Concentration Table (mg/L) of Lead Standard Curves and Sample Data
Concentration Level
1
2
3
4
5
6
Concentration of Standard Solutions (mg/L)
0.5
1.0
2.0
4.0
8.0
10
Absorbance of Standard Solutions (abs)
0.0073
0.0136
0.0290
0.0578
0.1112
0.1353
Absorbance of Waste Resin Powder (abs)
0.0024
Concentration of Waste Resin Powder (mg/L)
0.0000
Lead Concentration of Waste Resin Powder (mg/kg)
Not Detected
Standard Curve of Lead
Cadmium
Detection Sample
Cadmium
Burner Height
10mm
Acetylene Flow Rate
2.0L/min
Spectral Bandwidth
0.4nm
Wavelength
228.8nm
Lighting Way
AA
Lamp Current
3mA
Gradient Concentration Table (mg/L) of Cadmium Standard Curve and Sample Data
Concentration Level
1
2
3
4
5
Concentration of Standard Solutions (mg/L)
0.2
0.4
0.6
0.8
1.0
Absorbance of Standard Solutions (abs)
0.0667
0.0124
0.1775
0.2280
0.2748
Absorbance of Waste Resin Powder (abs)
0.0057
Concentration of Waste Resin Powder (mg/L)
0.0000
Cadmium Centration of Waste Resin Powder (mg/kg)
Not Detected
Standard Curve of Cadmium
Chromium
Detection Sample
Chromium
Burner Height
10mm
Acetylene Flow Rate
3.6L/min
Spectral Bandwidth
0.2nm
Wavelength
357.9nm
Lighting Way
AA
Lamp Current
5mA
Gradient Concentration Table (mg/L) of Chromium Standard Curve and Sample Data
Concentration Level
1
2
3
4
5
Concentration of Standard Solutions (mg/L)
0.2
0.4
0.6
0.8
1.0
Absorbance of Standard Solutions (abs)
0.0175
0.0388
0.0588
0.0786
0.0994
Absorbance of Waste Resin Powder (abs)
0.0130
Concentration of Waste Resin Powder (mg/L)
0.1519
Chromium Concentration of Waste Resin Powder (mg/kg)
37.7
Standard Curve of Chromium
3. Notes
3.1 Nitric acid and perchloric acid used in the experiment have strong oxidizing and corrosive properties, hydrochloric acid and hydrofluoric acid have strong volatility and corrosive properties, protective equipment should be worn in accordance with the requirements of the regulations, and the process of solution preparation and sample pre-processing operated in the fume hood.
3.2 The 10% ammonium chloride solution needs to be added to the standard solution and the sample simultaneously to ensure the consistency of the testing.
4. Conclusion
From the experimental results, the linear correlation coefficients of the lead, cadmium and chromium are all greater than 0.999. Lead and cadmium were not detected in the waste resin powder. Chromium was detected. The method is accurate, reliable, sensitive and can be used for the detection of heavy metals in waste resin powder.
Determination of Menthol Content in Mint by Gas Chromatogaphy
Determination of Menthol Content in Mint by Gas Chromatogaphy
In this paper, the chromatographic conditions are optimized with reference to the 2020 edition of the Chinese Pharmacopoeia, and a chromatographic column SK-WAX is used for the determination of menthol content in mint.
Keyword: Gas Chromatograph. FID Detector, Mint, Menthol
1. Experiment Method
1.1 Instrument Configuration
Table 1 Configuration List of Gas Chromatography
No
Module
Qty
1
GC6000 Gas Chromatography
1
2
FID6000 Detector
1
3
ASL6000 Autosampler
1
1.2 Test Conditions
Chromatography Column: SK-WAX, 30m*0.32mm*0.25μm
Temperature-Programmed： Keep the column at an initial temperature of 70°C for 4 minutes, heat up to 120°C at a rate of 1.5°C per minute, then to 200°C at a rate of 3°C per minute, and finally to 230°C at a rate of 30°C per minute and keep for 2 minutes;
Carrier Gas: high purity nitrogen, constant Current Mode
Column Flow Rate: 2mL/min
Inlet Temperature: 200°C
Detector Temperature: 300°C
Hydrogen flow rate： 35mL/min
Air Flow Rate: 300mL/min
Injection Volume: 1μL
Injection Method: Split-flow injection with a 5:1 split ratio.
1.3 Reagents and Experiment Material
1.3.1 Reagents
Mint Sample
Menthol Standard
Ethanol, AR.
1.3.2 Equipment
Needle Filter
The third sieve
1.4 Sample Preparation
1.4.1 Preparation of Reference Solution
Take the appropriate amount of menthol control, precision weighing, add ethanol to make a solution containing 0.2mg per 1mL.
1.4.2 Preparation of Test Solution
Take 2g of product powder (through the third sieve), precision weighing, placed in a stoppered V-shaped bottle, and tightly stoppered after precision addition of 50mL of ethanol. Weighing, ultrasonic treatment (power 250W, frequency 33kHz) for 30 minutes, cooled, and then weighing. Make up the lost weight with ethanol, shake well, filter and take the subsequent filtrate.
2 Result and Communication
2.1 Chromatogram of Reference Solution
Take the reference solution and analyzed according to the test conditions of 1.2, and the results are shown below.
As shown in the figure and data, the peak shape is symmetrical, there is no other peaks, and the separation degree is higher than 1.5, which is good and met the requirements.
Compound
Retention Time
Peak Area
Peak Height
Theoretical Plate Number
Menthol
18.262
564.820
48.485
56284
Take the reference solution, injected and detected 7 times sequential according to the test conditions in 1.2, the repeatability chromatogram as shown below. According to the test results, the retentionr time repeatability of the reference solution is 0.021% and the peak area repeatability is 0.47%, and the test repeatability is good.
2.2 Chromatogram of Test Solution
Take the test solution and analyzed according to the test conditions of 1.2, and the results as shown below. From the figure and the data, the peak shape is symmetrical, and there is no other peaks, and the separation degree is higher than 1.5, the separation is good and meets the requirements.
Compound
Retention Time
Peak Area
Peak Height
Theoretical Plate Number
Menthol
18.269
568.906
48.763
56738
Take the reference solution, injected and detected 7 times sequential according to the test conditions in 1.2, the repeatability chromatogram as shown below. According to the test results, the retention time repeatability of the reference solution is 0.038% and the peak area repeatability is 0.49%, and the test repeatability is good.
3. Conclusion
In this paper, a method for the determination of menthol in mint is established by Wayeal gas chromatograph GC6000. The results showed that the menthol peaks in the chromatogram is symmetrical, the repeatability of the retention time of 7 injections is less than 0.5%, and the repeatability of the peak area is less than 0.5%, which showed a good test repeatability. The theoretical plate number is much higher than 10000, which meets the requirements of the Chinese Pharmacopoeia. This product is calculated according to the dry product, the content of menthol in the test sample is 0.50%, which meets the requirement of Pharmacopoeia of no less than 0.20%. This method can be a reference for the determination of menthol content in mint.
Determination of Heavy Metals in soil by Atomic Absorption Spectrophotometer
Determination of Heavy Metals in soil by Atomic Absorption Spectrophotometer
1. Experiment Method
Keywords: Atomic absorption spectrophotometer, autosampler, graphite furnace, flame, soil, heavy metals.
1.1 Instrument Configuration
Table 1 Configuration Lists of AAS
No
Module
Qty
1
Atomic Absorption Spectrophotometer AA2310
1
2
Graphite Furnace Power GF2310
1
3
Autosampler AS2310
1
4
Cooling Circulator
1
5
High Purity Argon
1
6
Graphite Tube
1
7
Oilless Air Compressor
1
8
High Purity Acetylene
1
1.2 Reagents and Experiment Material
Nitric acid solution (1+99): Measure 10mL of nitric acid and slowly add to 990mL of water and mix well.
Pb Standard Solution:1000mg/L
Cd Standard Solution: 1000mg/L
Ni Standard Solution: 1000mg/L
1% diammonium hydrogen phosphate: take 1g of diammonium hydrogen phosphate in a 100mL volumetric flask, and fix the volume with ultrapure water;
Nitric Acid: GR
Hydrochloric Acid: GR
Hydrofluoric Acid: GR
perchloric acid: GR
One in ten thousand analytical balances
Electrothermal blast thermostatic drying oven
Digital display electric hot plate
Teflon crucible
1.3 Sample Pretreatment
Sample digestion: Weigh 0.2g of sample in a PTFE crucible, add one to two drops of water to moisten, add 10ml hydrochloric acid, 9ml nitric acid, 4ml hydrofluoric acid, and 2ml perchloric acid in turn, shake well, cover and heat on a hot plate at 150℃ for 6 hours, open the lid and continue to be heated in addition to silicon. In order to achieve a good effect of flying silica, it is necessary to shake the crucible frequently and drive the acid steaming until the content is viscous. Remove and cool slightly, add 0.5ml of nitric acid to dissolve the soluble residue, rinse the crucible lid and inner wall with water, transfer the whole amount to a 50ml volumetric flask, and fix the volume with ultrapure water, shake well. Store in PTFE reagent bottles for testing. Replace the sample with water and prepare a full program blank solution following the steps above. To be measured.
2. Conclusion and Discussion
2.1 Spectral Conditions for Lead
Heating Method
Graphite Furnace
Test Method
Peak Height
Injection Volume
20μL Sample + 5μL Diammonium Hydrogenphosphate
Bandwidth
0.4nm
Wavelength
283.3nm
Ignite
AA-BG
Lamp Current
5mA
Concentration Table of Standard Curves (μg/L)
Standard Curve
1
2
3
4
5
Leak Standard Solution
5.00
10.0
20.0
30.0
40.0
Standard Curve Testing
Linearity of Standard Curve
2.3 Spectral Conditions for Cadmium
Heating Method
Graphite Furnace
Testing Method
Peak Height
Injection Volume
15μL sample + 5μL 1% diammonium hydrogenphosphate
Bandwidth
0.4nm
Wavelength
228.8nm
Ignite
AA-BG
Lamp Current
4mA
Concentration Table of Standard Curves (μg/L)
Standard Curve
1
2
3
4
Cd Standard Solution
0.5
1.5
2.0
2.5
Standard Curve Testing
Linearity of Standard Curve
2.4 Spectral Conditions for Nickel
Heating Method
Flame
Burner Height
10mm
Acetylene Flow Rate
2.0L/min
Bandwidth
0.2nm
Wavelength
232.0nm
Ignite
AA
Lamp Current
4mA
Concentration Table of Standard Curve (μg/mL)
Standard Curve
1
2
3
4
5
Ni Standard Curve
0.5
1.0
1.5
2.0
2.5
Standard Curve Testing
Linearity of Standard Curve
3. Calculation of Results
Sample
No
Sample Volume (g)
Testing concentration
Content(mg/kg)
Theoretical Concentration (mg/kg)
Standard Deviation
Pb
1#
0.2005
16.2420μg/L
21
21±2
Qualified
1#- parallel
0.2009
17.6490μg/L
Cd
1#
0.2005
0.4897μg/L
0.12
0.14±0.02
Qualified
1#- parallel
0.2009
0.4991μg/L
Ni
1#
0.2005
0.1180μg/L
29
30±2
Qualified
1#- parallel
0.2009
0.1159μg/L
4. Note
Perchloric acid and nitric acid used in the experiment have strong oxidizing and corrosive properties, hydrochloric acid and hydrofluoric acid have strong volatility and corrosiveness, so reagent preparation and sample digestion should be carried out in a fume hood; protective equipment should be worn as required to avoid inhalation into the respiratory tract or contact with the skin and clothing during operation.
Determination of lbuprofen Extended-release Capsulesby High Performance Liquid Chromatography
Determination of lbuprofen Extended-release Capsulesby High Performance Liquid Chromatography
The analytical method presented herein, with reference to the determination of the content of ibuprofen extended-release capsules in the Pharmacopoeia of the People's Republic of China in the 2020 edition, was carried out on a Wayeal high-performance liquid chromatograph LC3200 series with a DAD detector.
1. Instrument Configuration and Experiment Method
1.1 Instrument Configuration
Table 1 Configuration List of Wayeal HPLC
No
Modular
Qty
1
P3210Q Quaternary Pump
1
2
CT3210 Column Oven
1
3
AS3210 Autosampler
1
4
DAD3260 DAD
1
5
Nova Atom PC18 4.6*250mm, 5μm
1
6
SmartLab Workstation
1
1.2 Experiment Method
1.2.1 Preparation of Reagents
No
Reagents
Purity
1
Methanol
Chromatography Pure
2
Acetonitrile
Chromatography Pure
3
Sodium Acetate
AR
4
Glacial Acetic Acid
GR
1.2.1.1 Test solution: take the contents under the loading difference, mix well, take appropriate amount (equivalent to about 0.1g of ibuprofen) into a 200mL measuring flask, add methanol 100mL, shaking for 30 minutes, dilute and fix the volume with water, sharking well, filtration, and remove the filtrate.
1.2.1.2 Reference Solution: Take 25mg of ibuprofen reference sample, weigh it precisely, put it in a 50mL measuring flask, add 25mL of methanol to make it dissolve, dilute and fix the volume with water, shake well.
1.2.1.3 Sodium acetate buffer solution: weigh 6.13g of sodium acetate, add 750mL of water to dissolve, and adjust the pH to 2.5 with glacial acetic acid.
1.2.2 Chromatography Conditions
Table 3 Chromatography Conditions
Chromatography Colimn
Nova Atom PC18, 4.6*250mm5μm
Mobile Phase
Ammonium acetate buffer solution
Flow Rate
1mL/min
Temperature
35°C
Wavelength
263nm
Injection Volume
20μL
2． Experiment Result
3.1 System Suitability
Fig 1 Chromatogram of Sample Testing
Table 4 Test Data of Test Sample
Sample
Compound
Retention Time
Peak Area
Peak Height
Theoretical Pate Number
Test Sample
ibuprofen
4.778
1204.748
223.865
18650
Figure 2 Chromatogram of Reference Sample
Table 5 Test Data Reference Sample
Sample
Compound
Retention Time
Peak Area
Peak Height
Theoretical Pate Number
Reference Sample
ibuprofen
4.781
1515.707
280.794
18541
From the chromatogram and table, it can be seen that the peaks of the test sample and reference sample are good, there are no other peaks around the target peaks, and the theoretical plate numbers are all above 2500 in pharmacopoeia, which satisfied the experimental requirements.
3.2 Repeatability
Fig 3 6 Injections Repeatability Chromatogram of Test Sample
Table 6 6 Injections Repeatability Data for Test Sample
Sample
No
Retention Time
Peak Area
Test Sample
1
4.778
1204.748
2
4.775
1205.853
3
4.778
1206.482
4
4.778
1206.091
5
4.781
1208.216
6
4.781
1209.01
RSD(%)
0.053
0.131
Fig 4 6 Injections Repeatability Chromatogram of Reference Sample
Table 7 6 Injections Repeatability Data for Reference Sample
Sample
No
Retention Time
Peak Area
Reference Sample
1
4.781
1515.707
2
4.781
1515.333
3
4.781
1518.024
4
4.781
1517.524
5
4.778
1515.806
6
4.778
1517.076
RSD (%)
0.036
0.073
Note: According to the data in the above table, the RSD of retention time for the test and reference sample are 0.053% and 0.036%, and the RSD of peak area is 0.131% and 0.073%, respectively. The repeatability results is good and satisfied the experimental requirements.
3.3 Sensitivity Testing
Figure 5 Chromatogram of Test Sample Diluted 2000 Times
Table 8 Test Data for Test Sample Diluted 2000 Times
Sample
Compound
Retention Time
Peak Area
Peak Area
Signal-to-Noise Ratio
Test Sample Diluted 2000 Times
ibuprofen
4.795
0.597
0.133
4.600
Note: According to the data shown in the above table, the peak area of test sample diluted in 200 times is 0.597 with a signal-to-noise ratio of 4.6, which is a good test result and meets the experimental requirements.
4. Notes
Glacial acetic acid has a strong irritating odor, so be careful to prepare the solution in a fume hood.
5. Conclusion
The analytical method presented herein, with reference to the determination of the content of ibuprofen extended-release capsules in the Pharmacopoeia of the People's Republic of China in the 2020 edition, was carried out on a Wayeal high-performance liquid chromatograph LC3200 series with a DAD detector. The experimental results showed that the peak shape of the system adaptability test is good, and there are no other peaks around the target peak, and the theoretical plate number is above 2500, which meet the requirements of pharmacopoeia. The RSD of the retention time is 0.053% and 0.036% and the RSD of peak area is 0.131% and 0.073% for ibuprofen test sample and reference sample. Repeatability results are good. The sensitivity test result of 2000 times dilution of the test material is good. All the above results meet the requirements of the pharmacopoeia method.
Determination of Sulfur Dioxide in Chenpi Samples by Ion Chromatography
Determination of Sulfur Dioxide in Chenpi Samples by Ion Chromatography
Ion chromatography has always been a research hotspot for the detection of sulfur dioxide in Chinese herbal, with its simple operation, high sensitivity and wide linear range, which is of practical value for the control of sulfur dioxide residue in pharmaceuticals.
In this experiment, the steam distillation method and the ion chromatography will be used to determine the content of sulfur dioxide in Chenpi. Wayeal ion chromatograph with conductivity detector, and KOH eluent. The method is simple to handle, with good recovery and high sensitivity, and is suitable for the determination of sulfur dioxide in Chenpi.
Keywords: Chenpi, sulfur dioxide, ion chromatograph
1. Experiment
1.1 Instruments and Reagents
Ion Chromatography: IC6200 Series ion chromatography with conductivity detector
Autosampler: AS2800
Anion Chromatography Column: HS-5A-P2, 250MM x 4.6mm, Sulfate ions in water(1000mg/L)
30% H2O2 solution;
Concentrated Hydrochloric Acid: Guaranteed reagent
Disposable Syringes (2mL)
Water-based Syringe Filter (0.22μm)
Electronic Balance, 1/10,000
The experimental water is prepared by the Wayeal ultrapure water purifier with a conductivity of 18.2 MΩ·cm (25 ℃).
1.2 Working Conditions
Column Temperature: 35°C
Cell Temperature : 40°C
Eluent : 30Mm KOH isocratie elution
Flow Rate : 1.0 mL/min
Suppressor Current: 90mA
Injection Volume: 25μL
1.3 Schematic Diagram of Steam Distillation
1.4 Sample Pretreatment
Take appropriate amount of sample (accurate to 0.0001g) to bottle A (two-necked flask), add 50mL deionized water, shaking, so that the dispersion is uniform, then connected to the water vapor distillation flask C. 20mL of 3% hydrogen peroxide solution was absorbed in Bottle B. The lower end of the absorbing tube was inserted below the level of the absorbing solution. Add 5mL of hydrochloric acid along the wall of bottle A, quickly close the stopper, and begin distillation, keeping bottle C boiling and adjusting the distillation fire so that the effluent from the end of the absorber tube flows at a rate of about 2mL/min. Distill until the total volume of the solution in bottle B was about 95mL (30~40min), wash the tail pipe with water and transfer it to a volumetric flask, fix the volume to the scale, shake it well, let it stand for 1h, filtered through 0.22μm aqueous filter membrane, choose the appropriate dilution times, and test and analyze it on the machine.
2. Result and Discussion
2.1 Linearity Test
0.1mg/L, 0.2mg/L, 0.5mg/L, 1.0mg/L, 2.0mg/L, 3.0mg/L of standard working curves of were pipetted respectively, and you will get the multi-point overlap chromatography of the standard curve according to the 1.2 working conditions, as shown in Fig. 1, linear equations as shown in Table1, and the linear correlation coefficients of sulfate under this chromatographic condition is above 0.999, which is good linearity.
Fig1 Overlap Chromatogram of SO4 Standard Curve
Fig 2 Standard Curve of SO4
Table 1 Linear Equation of Standard curve
No
Ions
Linear Equation
Correlation Coefficient R
1
So42-
y=14.32737x-0.76329
0.99926
2.2 Sample Testing
2.2.1 Sample Content Testing
The pre-treated samples were detected under the 1.2 working conditions. The sample chromatogram as shown in Fig. 3 and Fig. 4, the chromatographic peaks are symmetrical, with good separation and no other peaks, and the final content of sulfur dioxide in the sample as shown in Table 2.
Fig 3. Chromatogram of Sample 1
Fig 4. Chromatogram of Sample 2
Table 2 Sample Results Analysis
Sample
Weighing Sample/g
Ions
Concentration(mg/L)
SO2 Content(g/kg)
Blank
/
SO42-
0.272
/
Sample 1
2.5551
SO42-
1.417
0.030
Sample 2
2.2370
SO42-
0.920
0.019
2.2.2 Sample Repeatability Testing
Fig 4 Repeatability Chromatogram of Sample 1
Table 3 Repeatability Results of Sample 1
Sample
Weighing Sample/g
Retention Time/min
Peak Area
Concentration mg/L
Sample 1
2.5551
12.307
19.615
1.422
12.290
19.627
1.423
12.267
19.327
1.402
12.250
19.632
1.424
12.230
19.380
1.406
12.247
19.640
1.424
Average Value
12.265
19.537
1.417
RSD%
0.235
0.732
0.705
3. Conclusion
An ion chromatographic method was established for the determination of sulfur dioxide in Chenpi samples by using Wayeal IC6200 series ion chromatograph equipped with a conductivity detector. The samples were pre-treated and then separated by an ion chromatographic column and quantified by external standard method, which was able to qualitatively and quantitatively analyze the sulfur dioxide in Chenpi. The method is simple and easy to use, with good reproducibility, sensitivity and accuracy, which can be adopted for the determination of sulfur dioxide in Chenpi.
Determination of Heavy Metals in Waste Resin Powder by Wayeal Atomic Absorption Spectrophotometer
Determination of Heavy Metals in Waste Resin Powder by Wayeal Atomic Absorption Spectrophotometer
In this paper, with reference to the standard of "HJ 749-2015 Determination of Total Chromium in Solid Waste Flame Atomic Absorption Spectrophotometry" "HJ 786-2016 Determination of Lead, Zinc and Cadmium in Solid Waste Flame Atomic Absorption Spectrophotometry", an analytical method was established for the determination of the content of heavy metal elements in waste resin powder by flame atomic absorption method.
Keywords: Atomic Absorption Spectrophotometer; flame, waste resin powder; lead; cadmium; chromium.
1. Experiment Method
1.1 Instrument Configuration
Table 1 Configuration List of Atomic Absorption Spectrophotometer
No
Name
Qty
1
Atomic Absorption Spectrophotometer AA2310
1
2
Air Compressor
1
3
High-purity Acetylene
1
4
Lead Hollow Cathode Lamp
1
5
Cadmium Hollow Cathode Lamp
1
6
Chromium Hollow Cathode Lamp
1
1.2 Reagents and Instruments
1.2.1 Lead Standard Solution(1000μg/ml)
1.2.2 Cadmium Standard Solution(1000μg/ml)
1.2.3 Chromium Standard Solution(1000μg/ml)
1.2.4 Ammonium Chloride: AR
1.2.5 Nitric Acid: GR
1.2.6 Hydrochloric Acid: GR
1.2.7 Hydrofluoric Acid: GR
1.2.8 Perchloric Acid: GR
1.2.9 30% Hydrogen Peroxide: GR
1.2.10 One in ten thousand analytical balances
1.2.11 Digital display electric hot plate
1.3 Pre-processing
1.3.1 Pre-processing of Lead and Cadmium Samples
Take 0.2g of sample (accurate to 0.1mg) into a 50ml PTFE crucible. After wetting with water, 5ml of hydrochloric acid was added and the sample was heated on a hot plate in a fume hood at about 120 ℃ to initially disintegrate the sample, and then removed and cooled slightly after evaporation until about 3m remained. Add 8ml of nitric acid, 8ml of hydrofluoric acid and 4ml of perchloric acid, cover and heat at about 160 ℃ on a hot plate for 3h. Open the lid, the electric heating plate temperature control at 180 ℃ to continue heating, and often shake the crucible. When heated to a thick white smoke, cover to fully decompose the black organic carbons. After the black organic matter on the crucible wall disappears, open the lid, drive away the white smoke and steam until the contents are viscous. Take down the crucible, slightly cold, add 0.2mL nitric acid to dissolve the soluble residue, after cooling, transfer the whole amount to 50ml volumetric flask, rinse the crucible lid and inner wall with appropriate amount of experimental water, the washing solution was incorporated into 50ml volumetric flask, and the fix the volume with experimental water, shaken well, and then left to be measure. If there are undissolved particles in the digested solution, filtering and centrifugation or natural precipitation are required. (Note: Do not allow a lot of bubbles to come out when heating, otherwise it will cause loss of the sample.)
1.3.2 Pre-processing of Chromium Sample
Take 0.2g (accurate to 0.0001g) of sample into a 50ml PTFE crucible. After wetting with water, 10ml of concentrated hydrochloric acid was added and the sample was heated on a hot plate in a fume hood at 50°C to initially decompose the sample. When evaporated to about 3ml, add 5ml of concentrated nitric acid, 5ml of hydrofluoric acid, cover and heat on the hot plate at about 120~130 ℃ for 0.5~1h, then open the lid, drive away the white smoke and steam until the contents are in the form of liquid beads in a non-flowing state (observe while hot). Depending on the condition of digestion, add 3ml of concentrated nitric acid, 3ml of hydrofluoric acid, 1ml of hydrogen peroxide, and repeat the above digestion process. Take down the crucible, slightly cold, add 0.2mL nitric acid to dissolve the soluble residue, transfer all the test solutions to a 50ml volumetric flask, add 5ml of 110% ammonium chloride solution, and fix the volume with experimental water, left to be measured. (Note: the total amount of 30% hydrogen peroxide added shall not exceed 10ml.)
2. Results and Discussion
Lead
Detection Sample
Lead
Burner Hight
10mm
Acetylene Flow Rate
2.0L/min
Spectral Bandwidth
0.4nm
Wavelength
283.3nm
Lighting Way
AA
Lamp Current
5mA
Gradient Concentration Table (mg/L) of Lead Standard Curves and Sample Data
Concentration Level
1
2
3
4
5
6
Concentration of Standard Solutions (mg/L)
0.5
1.0
2.0
4.0
8.0
10
Absorbance of Standard Solutions (abs)
0.0073
0.0136
0.0290
0.0578
0.1112
0.1353
Absorbance of Waste Resin Powder (abs)
0.0024
Concentration of Waste Resin Powder (mg/L)
0.0000
Lead Concentration of Waste Resin Powder (mg/kg)
Not Detected
Standard Curve of Lead
Cadmium
Detection Sample
Cadmium
Burner Height
10mm
Acetylene Flow Rate
2.0L/min
Spectral Bandwidth
0.4nm
Wavelength
228.8nm
Lighting Way
AA
Lamp Current
3mA
Gradient Concentration Table (mg/L) of Cadmium Standard Curve and Sample Data
Concentration Level
1
2
3
4
5
Concentration of Standard Solutions (mg/L)
0.2
0.4
0.6
0.8
1.0
Absorbance of Standard Solutions (abs)
0.0667
0.0124
0.1775
0.2280
0.2748
Absorbance of Waste Resin Powder (abs)
0.0057
Concentration of Waste Resin Powder (mg/L)
0.0000
Cadmium Centration of Waste Resin Powder (mg/kg)
Not Detected
Standard Curve of Cadmium
Chromium
Detection Sample
Chromium
Burner Height
10mm
Acetylene Flow Rate
3.6L/min
Spectral Bandwidth
0.2nm
Wavelength
357.9nm
Lighting Way
AA
Lamp Current
5mA
Gradient Concentration Table (mg/L) of Chromium Standard Curve and Sample Data
Concentration Level
1
2
3
4
5
Concentration of Standard Solutions (mg/L)
0.2
0.4
0.6
0.8
1.0
Absorbance of Standard Solutions (abs)
0.0175
0.0388
0.0588
0.0786
0.0994
Absorbance of Waste Resin Powder (abs)
0.0130
Concentration of Waste Resin Powder (mg/L)
0.1519
Chromium Concentration of Waste Resin Powder (mg/kg)
37.7
Standard Curve of Chromium
3. Notes
3.1 Nitric acid and perchloric acid used in the experiment have strong oxidizing and corrosive properties, hydrochloric acid and hydrofluoric acid have strong volatility and corrosive properties, protective equipment should be worn in accordance with the requirements of the regulations, and the process of solution preparation and sample pre-processing operated in the fume hood.
3.2 The 10% ammonium chloride solution needs to be added to the standard solution and the sample simultaneously to ensure the consistency of the testing.
4. Conclusion
From the experimental results, the linear correlation coefficients of the lead, cadmium and chromium are all greater than 0.999. Lead and cadmium were not detected in the waste resin powder. Chromium was detected. The method is accurate, reliable, sensitive and can be used for the detection of heavy metals in waste resin powder.
Determination of Salidroside in Pharmaceuticals by High Performance Liquid Chromatography（HPLC）
Abstract
Purpose: Determination of Salidroside in Pharmaceuticals by High Performance Liquid Chromatography（HPLC）
Method: C18 column, 4.6*250mm, 5μm;
Wavelength: 275nm;
Mobile Phase A: Water; mobile phase B: methanol;
Flow Rate 1.0ml/min;
Temperature: 30°C;
Injection Volume: 5μl.
A standard curve was established and the content of the target was calculated by the external standard method.
Keywords: HPLC, UV Detector, Herbal, Salidroside
1. Experiment Method
1.1 Instrument Configuration
Wayeal LC3200 Series HPLC
No.
Name
Qty
1
LC3200 Series HPLC
1
2
P3200 Binary Pump
1
3
UV3200 Detector
1
4
CT3200 Column Oven
1
5
AS3200 Autosampler
1
Table 1 System Configuration of HPLC
1.2 Test Conditions
Column: C18, 5μm, 4.6*250mm
Temperature: 30°C
Wavelength: 275nm
Flow rate: 1.0ml/min
Mobile phase: A: water; B: methanol
Injection volume: 5μL
Gradient Condition:
T (min)
A Water (%)
B Methanol (%)
0
95
5
15
90
10
35
85
15
36
95
5
50
95
5
1.3 Instrument, Reagents and Consumables
Reagents: ultrapure water, Methanol(GR)
Standards: Salidroside (99.7%)
Auxiliary device: chemical balance; solvent filter; ultrasonic cleaners
Experimental materials: filter membrane: aqueous phase filter membrane 0.45μm
1.4 Preparation of Solutions
1.4.1 Standard Solutions: Take appropriate amount of salidroside standard into a volumetric flask and dissolved in methanol to make the concentration of 0.0084125mg/mL, 0.016825mg/mL, 0.03365mg/mL, 0.0673mg/mL, 0.1346mg/mL, 0.2692mg/mL, 0.673mg/mL.
1.4.2 Sample Preparation: Take 1.0022g of sample 1 into a volumetric flask, add methanol and dissolve to 25mL. Take 1.0794g of sample 2 into a volumetric flask, add methanol and dissolve to 25mL.
2 Results and Discussion
2.1 System Suitability
Fig 1 Chromatogram of Salidroside Standard
No
Compound
Retention Time
Peak Area
Peak Height
Tailing Factor
Theoretical Plate Number
1
Salidroside
36.262
812.469
31.885
1.035
45724
Table 2 Chromatography Parameters of Salidroside Standards
Analysis: The test results of salidroside were good with symmetrical peaks and high theoretical plate number.
2.2 Standard Curve
Fig 2 Superimposed chromatogram of Salidroside Standard solutions
Fig 3 Curve Equation and Correlation Coefficient of Salidroside Standard Solutions
Analysis: The linear range of salidroside standard curve is good, r>0.999.
2.3 Repeatability
Fig 4 Repeatability Chromatogram of Salidroside Standards (n=6)
No
Sample
Retention Time
Peak Area
1
0.2692mg/L standard solution
36.265
807.365
2
36.262
812.469
3
36.247
812.562
4
36.224
815.145
5
36.228
813.374
6
36.272
814.529
Average
36.250
812.574
RSD(%)
0.055
0.340
Table 3 Repeatability Chromatographic Parameters Table of Salidroside (n=6)
Analysis: 6 injections of 0.2692 mg/L salidroside show good reproducibility, and the RSD value of retention time is 0.055% and the RSD value of peak area is 0.340%.
2.4 Sample 1
Fig 5 Chromatogram of Sample 1
No
Compund
Retention Time
Peak Area
Peak Height
Tailing Factor
Theoretical Plate Number
concentration
1
Salidroside
36.201
185.337
7.335
1.038
47306
0.061933 mg/L
Table 4 Chromatography Parameters of Sample 1
Analysis: The content of salidroside in the sample 1 was 0.061933 mg/L, which was calculated according to the standard curve equation.
2.5 Sample 2
Fig 6 Chromatogram of Sample 2
No
Compound
Retention Time
Peak Area
Peak Height
Tailing Factor
Theoretical Plate Number
concentration
1
Salidroside
36.214
197.232
7.750
0.998
46217
0.065566
Table 4 Chromatography Parameters of Sample 2
Analysis: The content of salidroside in the sample 2 is 0.065566mg/L, which iscalculated according to the standard curve equation.
3. Conclusion
Wayeal LC3200 series high performance liquid chromatograph with UV detector is used to detect salidroside; the test result is good with symmetrical peaks and high theoretical plate number. The linear range of the standard curve is good, r>0.999. The repeatability is good and 6 injections of 0.2692 mg/L salidroside has good reproducibility, and the RSD value of retention time is 0.055% and the RSD value of peak area is 0.340%. The content of salidroside in sample 1 is 0.061933 mg/L, and the content of salidroside in sample 2 is 0.065566 mg/L, which are calculated according to the standard curve equation.
Guo Chengzhan, Secretary of Party Committee and Chairman of China Environmental Protection Industry Association Visited Wayeal for Research and Guidance
Guo Chengzhan, Secretary of Party Committee and Chairman of China Environmental Protection Industry Association Visited Wayeal for Research and Guidance
On July 27th, Guo Chengzhan, Secretary of Party Committee and Chairman of China Environmental Protection Industry Association (CEPIA), and his delegation visited Wayeal for a research and discussion to understand the current situation of the enterprise and listen to the demands and suggestions.
In the seminar, Wayeal reported the development of the enterprise, the scientific research achievements and the future development plan. With the national "14th Five-Year Plan" and "Double Carbon" target, Wayeal actively responds to the needs of the country and enterprises, and launches "Digital Intelligence Double Carbon Integrated Solution", "Fine Particulate Matter - Ozone Synergy Control Solution", as well as comprehensive solutions in various scenarios such as air environment monitoring, water quality online monitoring, fixed pollution source monitoring and emergency monitoring.
During the exchange, President Guo Chengzhan affirmed the R&D strength and scientific research achievements of Wayeal, and highly praised its determination to attach importance to independent R&D and technological innovation in the past 20 years and insist on "not forgetting the original intention and replacing imports". He also said that with the high-quality development of ecological and environmental protection industry, the establishment of ecological and environmental monitoring and supervision system will slowly change from "human defense" to "technology defense". He hope that Wayeal will aim at the world's cutting-edge technology, play a leading role in the industry, adhere to scientific and technological innovation, and make greater contributions to the localization of high-end environmental monitoring instruments and equipment.
After the meeting, Mr. Zang Mu, Chairman of Wayeal, took President Guo Chengzhan and his party to visit the exhibition hall, R&D lab and production workshop of Wayeal.
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