Speciation analysis of inorganic arsenic by microchip capillary electrophoresis coupled with hydride generation atomic fluorescence spectrometry

A novel method for speciation analysis of inorganic arsenic was developed by on-line hyphenating microchip capillary electrophoresis (chip-CE) with hydride generation atomic fluorescence spectrometry (HG-AFS). Baseline separation of As(III) and As(V) was achieved within 54 s by the chip-CE in a 90 mm long channel at 2500 V using a mixture of 25 mmol l−1 H3BO3 and 0.4 mmol l−1 CTAB (pH 8.9) as electrolyte buffer. The precisions (RSD, n = 5) ranged from 1.9 to 1.4% for migration time, 2.1 to 2.7% for peak area, and 1.8 to 2.3% for peak height for the two arsenic species at 3.0 mg l−1 (as As) level. The detection limits (3σ) for As(III) and As(V) based on peak height measurement were 76 and 112 μg l−1 (as As), respectively. The recoveries of the spikes (1 mg l−1 (as As) of As(III) and As(V)) in four locally collected water samples ranged from 93.7 to 106%.