Determinations of Monosaccharides and Disaccharides in Beverages by Capillary HPAE-PAD

Importance of the Topic

Accurate determination of mono- and disaccharides in beverages underpins quality control, labeling compliance and formulation consistency across the food and beverage industry.
Monitoring sugar profiles helps confirm source materials (cane sugar, beet sugar, high-fructose corn syrup) and supports consumer health initiatives by tracking total and relative sugar consumption.

Objectives and Study Overview

This study demonstrates a direct, derivatization-free method for quantifying glucose, fructose and sucrose in diverse beverage matrices using capillary high-performance anion-exchange chromatography with pulsed amperometric detection (HPAE-PAD).
Different dilution schemes (2× to 10 000×) were applied to carbonated drinks, tea, fruit juices, coconut water and low-sugar beverages to evaluate method robustness and linearity.

Methodology and Instrumentation

The method employs a Thermo Scientific Dionex ICS-4000 Dedicated Capillary HPIC system equipped with a CarboPac PA20 capillary column (0.4×150 mm), inline KOH eluent generator (Reagent-Free IC) and pulsed amperometric gold electrode detection referenced to Ag/AgCl.
An isocratic 10 mM KOH eluent at 0.008 mL/min (30 °C column, 27 °C compartment) separates sugars, while gold-on-PTFE working electrodes with 0.001″ or 0.015″ gaskets enable sensitivity tuning.
Sample preparation involves appropriate dilutions in 18 MΩ-cm deionized water and degassing to prevent contamination.

Main Results and Discussion

Baseline-resolved separation (Rs>1.6) of six standard carbohydrates achieved linear response (R2>0.99) from 0.1 to 10 mg/L (0.001″ gasket) and 1 to 200 mg/L (0.015″ gasket).
Analysis of a 5000× diluted carbonated beverage showed only glucose and fructose peaks, indicating high-fructose corn syrup use.
A 10 000× diluted apple cider displayed primarily fructose with minimal sucrose, consistent with no added sugar.
Tea and coconut water samples at 500× dilution yielded reliable sugar profiles, while low-sugar fruit beverages required only 2× dilution to detect trace levels (<1 g/L total sugar).
Thicker gaskets reduced the need for extensive dilution, though they required more frequent column washes to maintain retention stability.

Benefits and Practical Applications of the Method

Direct HPAE-PAD analysis eliminates costly derivatization and reduces reagent preparation errors via inline eluent generation.
Capillary flow rates (µL/min) minimize eluent consumption (<15 mL/day) and waste, while cartridge lifetimes exceed 18 months.
The approach supports continuous 24/7 operation for high-throughput QA/QC labs and research facilities.
High sensitivity and wide linear range accommodate both low-sugar reformulated products and high-sugar formulations without extensive re-optimization.

Future Trends and Potential Applications

Integration of capillary HPAE-PAD with mass spectrometry may broaden analyte coverage to oligosaccharides, organic acids and artificial sweeteners.
Further miniaturization and microfluidic-based systems can accelerate real-time monitoring of sugar content in production lines.
Automation of sample handling, on-line dilution and data analysis will streamline workflows in industrial and regulatory laboratories.
Advances in electrode materials and waveforms could further extend detection limits and electrode longevity.

Conclusion

The presented capillary HPAE-PAD method on the Dionex ICS-4000 platform delivers rapid, precise and sensitive sugar profiling across a range of beverage types and concentrations.
By combining inline eluent generation, low-volume flow cells and selectable gasket thickness, the method offers flexibility for diverse analytical needs while reducing operational costs and waste.

Reference

• Christison T., Zhang A., Lopez L., Thermo Fisher Scientific Technical Note TN70646-EN: HPAE-PAD Determinations of Monosaccharides and Disaccharides in Beverages, 2017.
• Thermo Fisher Scientific Application Note AN 282: Rapid and Sensitive Determination of Biofuel Sugars by Ion Chromatography, 2012.
• Thermo Fisher Scientific Technical Note TN 136: Configuring a High-Pressure Dedicated Capillary IC System for Electrochemical Detection, 2013.