Determination of alditols by capillary electrophoresis with indirect laser-induced fluorescence detection

A novel method was developed based on capillary electrophoresis with indirect laser-induced fluorescence detection for the determination of alditols including xylitol, sorbitol, arabinitol and mannitol. The baseline separation was achieved with a capillary with 30 μm inner diameter and running buffer (pH 9.6) composed of 40 mM sodium tetraborate, 5% (v/v) methanol, 10(-5)M sodium fluorescein as background fluorescence. Calibration curves (0.2-2.0 mg mL(-1)) showed good linear correlations (r>0.999). The detection limits of the alditols were in the range of 19.0-24.4 μg mL(-1). The intra-day and inter-day RSDs for migration times and peak areas were less than 1.6% and 4.3%, respectively. The average recoveries were in the range of 99.6-105.5%. The developed method was successfully applied to determination of alditols in different real samples, and the results were compared with those of capillary electrophoresis with indirect ultraviolet detection method.