Determination of arsenic species by capillary zone electrophoresis with large-volume field-amplified stacking injection

Determination of arsenic species by large-volume field amplified stacking i njection-capillary zone electrophoresis (LV-FASI-CZE) is reported in this p aper. Whole column injection was employed. The optimum buffer pH for the se paration of weak acids was discussed. It was found that the optimum buffer to analyze the stacked arsenate (As(V)), monomethylarsonate (MMA), and dime thylarsinate (DMA) was 25 mm phosphate at pH 6.5. However, the optimum buff er to analyze the concentrated arsenite (As(III)) was 20 mm phosphate - 10 mm borate at pH 9.28. The limits of detection of the method developed were 0.026 mg/L for As(III), 0.023 mg/L for As(V), 0.043 mg/L for MMA, and 0.018 mg/L for DMA. An enrichment factor of 34-100 for several arsenic species w as obtained. In the end, this method was applied to determine the arsenic c oncentration in the environmental reference materials to show the usefulnes s of the method developed.