Analysis of halides, oxyhalides and metal oxoacids by capillary electrophoresis with suppressed electroosmotic flow

A rapid and easy method for the determination of halides, oxyhalides and metal oxoacids by capillary electrophoresis was developed. This is the first paper to report their simultaneous analysis. Electroosmotic flow was suppressed more than 40-fold by using a poly(ethyleneglycol)-coated capillary, compared with that in a bare fused-silica capillary under similar conditions. Using this capillary, the separation of eleven anions was accomplished. Anion migration was dependent only on their mobility and detection was carried out directly with a diode-array detector. The R.S.D.s were better than 0.6% for migration time and between 1.0% and 3.4% for peak area. Calibration graphs for all the anions were linear, with correlation coefficients better than 0.9995. Using stacking sample preconcentration, the achievable lower detection limits were found to be in the range 14-260 μg 1^-1. This represents a 33-43-fold increase in sensitivity over the results obtained by using 200 mbar·s pressure injection.