Analysis of carbohydrates in beverages by capillary electrophoresis with precolumn derivatization and UV detection

Abstract

We describe a simple, selective capillary electrophoretic method using precolumn derivatization and UV detection at 280 nm to determine carbohydrates in beverages. Three carbohydrates, glucose, maltose and maltotriose, were analysed. The labelling reagent was p-aminobenzoic acid (PABA). Under optimised conditions the labelling reaction took 1 h at 40 °C in the presence of 250 mM PABA solution and 20% acetic acid. A fused silica capillary column was used together with an electrophoretic medium of 20 mM borate buffer (pH 10.2). The analysis was completed in less than 12 min. The detection limits for the three analytes were in the range of 3.82–4.14 mg l −1. The method could be readily applied to the analysis of carbohydrates in several beverages. Sample preparation was minimal, consisting only of degassification, dilution and/or filtration.