CZE Analysis of Artificial Sweeteners and Preservatives in Drinks

Significance of the Topic

Capillary electrophoresis (CZE) provides a rapid and efficient alternative to conventional HPLC methods for the analysis of artificial sweeteners and preservatives in beverage and tablet matrices.
By eliminating complex derivatization steps and exploiting a transparent borate buffer at 192 nm, the technique achieves sensitive detection in the low nanogram range.

Study Objectives and Overview

This application note aims to demonstrate a unified CZE method capable of separating and confirming common sweeteners—such as aspartame, saccharin, cyclamate, and acesulfame—and typical preservatives including benzoic acid, sorbic acid, and PHB esters, within a single analytical run.
Both model standards and real samples (diet cola, carbonated drinks, sweetened coffee, and tablet formulations) were evaluated.

Methodology and Instrumentation

Analyses were carried out using an Agilent CE system with diode-array detection and CE ChemStation software.
Separations employed a 50 µm id fused-silica capillary (64.5 cm total length, 56 cm effective) set at 25 °C and a 20 mM sodium tetraborate buffer (pH 9.4).
Samples were hydrodynamically injected (50 mbar, 2 s) and separated under 30 kV.
UV detection at 192 nm (2 nm bandwidth) combined with spectral library matching and peak purity checks enabled unambiguous compound identification.

Main Results and Discussion

The method achieved baseline resolution of all target analytes within 8 minutes.
Migration time repeatability was better than 0.15 % RSD, and peak area precision ranged from 1 % to 7 % RSD.
Spectral overlays confirmed the purity of peaks and revealed phenomena such as an isosbestic point in acesulfame tautomerisation.
Real sample analyses demonstrated clear detection of sweeteners and preservatives in beverages and tablets without interference.

Benefits and Practical Applications

This CZE approach reduces sample preparation time by avoiding multiple derivatization steps required in HPLC methods.
Combined detection and identification in a single run streamlines quality control workflows in food and beverage laboratories.
The low detection limits and high reproducibility meet regulatory and routine QA/QC requirements.

Future Trends and Potential Applications

Integration of CZE with mass spectrometry detection could further enhance identification and quantitation of emerging sweetener analogues.
Automation of buffer replenishment and capillary maintenance may improve throughput for high-volume testing.
The method can be extended to analyze broader classes of food additives and degradation products.

Conclusion

Capillary electrophoresis with UV-visible spectral library matching offers a fast, reliable, and sensitive platform for simultaneous screening of artificial sweeteners and preservatives in drinks and tablets.
The simplified workflow and robust performance position CZE as a valuable tool for food analysis laboratories.

References

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