Reproducible chiral capillary electrophoresis of methamphetamine and its related compounds using a chemically modified capillary having diol groups

Excellent reproducibility of chiral capillary electrophoresis for methamphetamine (MA) and its related compounds was obtained using a chemically modified capillary having diol groups. The data were compared with those using an untreated fused-silica capillary and a poly(vinyl alcohol) (PVA)-coated capillary. For five replicate analyses of a standard mixture, relative standard deviations (RSDs) of the migration times of analytes with diol or PVA-coated capillaries were less than 0.1%, which were lower than those obtained with an untreated fused-silica capillary (ca. 0.4%). The diol capillary gave reproducible migration times especially in analyses of real samples, such as crude human urine. In the analyses of five spiked urine samples, the RSD values of migration times of analytes with the diol capillary were not greater than 0.14%, which were much lower than those obtained with the PVA-coated capillary (ca. 1.5%). The proposed method was successfully used for chiral analyses of actual urine samples of MA addicts.