Separation and Determination of Carbohydrates in Food Samples by Capillary Electrophoresis Using Dynamically Coating the Capillary with Indirect UV Detection

Abstract

In this study, the separation and determination of carbohydrates in food samples were developed by capillary electrophoresis using dynamically coating the capillary with indirect UV detection. The polycationic polymers of hexadimethrine bromide (HDB) were used as electroosmotic flow (EOF) modifier to reverse the EOF. A highly alkaline pH condition was used in order to charge every carbohydrate negatively. Several important parameters influencing buffer concentration, pH, and HDB concentration were optimized. The optimal background electrolyte composed of 20 mmol L−1 sorbic acid, 0.005 % (w/v) HDB, and 40 mmol L−1 NaOH at pH 12.2. Under optimal conditions, 32 carbohydrates including mono-, di-, oligosaccharides, and sugar alcohols were separated in less than 12 min. The proposed method provided a good linearity, low limits of detection, and good repeatability of the carbohydrates. This method was then utilized to analyze carbohydrates in food samples. The results indicated that the developed method is an excellent alternative for the carbohydrate routine analysis in the food field.