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

Fig 1 Multi-point Overlap Chromatogram of Standard Curves

Table 2 Linear Equations of Acetic Acid and Sulfate Ion

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

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.