Determination of Sugar Alcohol in Food by High Performance Liquid Chromatography

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

Table 4 6 Injections of Retention Time Repeatability

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

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.