DETERMINATION OF CARBOHYDRATES AS THEIR DANSYLHYDRAZINE DERIVATIVES BY CAPILLARY ELECTROPHORESIS WITH LASER-INDUCED FLUORESCENCE DETECTION

A mixture of mono- and disaccharides was derivatized with dansylhydraz ine in a relatively fast chemical reaction (15 min) which is selective toward aldehydes and ketones. The products of the derivatization reac tion were then separated by capillary electrophoresis (CE) using laser -induced fluorescence (LIF) as the detection mode. The smallest amount of carbohydrate derivatized and determined by CE/LIF was 10 pmol cont ained in 100 mu L of the final reaction mixture. The CE/LIF method pro vided a linear response for the carbohydrates tested (over 2-3 orders of magnitude), with a limit of detection of 100 amol. Separation effic iencies over 250 000 theoretical plates were obtained. The procedure w as used to analyze a tear fluid sample to demonstrate the applicabilit y of the method for the glucose determination in small volumes of biol ogical samples.