Direct Carbohydrate Analysis in Beverages and Foods Using Pulsed Amperometric Detection or Charged Aerosol Detection

Significance of the Topic

Carbohydrate analysis in food and beverages is critical for nutritional labeling, quality control, detection of adulteration and process monitoring. Direct detection methods reduce sample preparation time and improve assay reproducibility.

Objectives and Overview

This work presents direct HPLC approaches using pulsed amperometric detection (PAD) and charged aerosol detection (CAD) for quantifying carbohydrates without derivatization. Three HPLC-PAD methods target seven simple sugars, lactose/lactulose in milk and malto-oligosaccharide profiling in beer. Two HPLC-CAD methods employ HILIC separation for rapid analysis of fruit juices and sports beverages.

Methodology

• HPLC-PAD: Anion-exchange chromatography under alkaline conditions with a gold working electrode and four-pulse waveform to clean the electrode and enhance selectivity.
• Simple sugar method: Isocratic separation of glucose, fructose, sucrose, maltose and other common sugars in juices, sodas and syrups.
• Lactose/lactulose assay: Separation of milk sugars in 35 min cycle with 1% perchloric acid protein precipitation.
• Beer profiling: Gradient run with sodium hydroxide and acetate to resolve oligosaccharides up to DP13–15 and simple sugars.
• HPLC-CAD: HILIC chromatography on amide or mixed-mode columns for universal detection of non-volatile and semi-volatile carbohydrates and electrolytes.

Instrumentation

• Thermo Scientific Dionex Ultimate U3000 HPLC system
• Thermo Scientific Dionex ECD-3000RS electrochemical detector with gold working electrode
• Thermo Scientific Corona Veo and Corona Veo RS Charged Aerosol Detectors
• Anion-exchange columns (e.g. CarboPac PA20) and HILIC columns (e.g. Accucore 150-Amide-HILIC, Acclaim Trinity P2)

Main Results and Discussion

• HPLC-PAD achieved complete separation of seven simple sugars within 12 min and reliable quantification in beverages.
• Lactose and lactulose in milk were resolved within 35 min with minimal cleanup.
• Beer profiling distinguished malto-oligosaccharides up to DP13–15 alongside mono- and disaccharides.
• HPLC-CAD provided six-minute carbohydrate profiles in fruit juices and simultaneous analysis of sugars and electrolytes in sports drinks.

Benefits and Practical Applications

• Elimination of derivatization accelerates sample throughput and reduces variability.
• Pulsed amperometric detection offers high sensitivity for carbohydrates lacking chromophores.
• Charged aerosol detection provides universal response for non-volatile analytes in diverse matrices.
• Methods support routine QA/QC, nutritional testing and authenticity screening.

Future Trends and Potential Applications

Emerging uses include integration of universal detectors for vitamins, amino acids, lipids and preservatives. Miniaturized and automated HPLC-PAD/CAD platforms will enhance throughput. Adaptation to complex matrices such as plant extracts, novel sweeteners and dairy-based beverages is anticipated.

Conclusion

Direct HPLC-PAD and HPLC-CAD methods deliver fast, derivatization-free carbohydrate analysis with high sensitivity and selectivity. These workflows offer robust solutions for food and beverage quality assessment and can be readily extended to broader analyte classes.

References

No specific literature references were provided in the source document.