Analysis of arsenic species in realgar bioleaching solution by capillary zone electrophoresis

Realgar was bioleached by Acidithiobacillus ferrooxidans BY-3. A capillary zone electrophoresis (CZE) method was developed to analyze arsenic species in realgar bioleaching solution. This way can simultaneously separate arsenic compounds including arsenite (iAsIII), arsenate (iAsV), monomethylarsenic (MMAV) and dimethylarsenic acid (DMAV). Borate and cetyltrimethylammonium bromide (CTAB) were selected to compose a background electrolyte (BGE). Identification and quantification of the arsenic species at µg/ml levels was possible by use of direct UV detection at 195 nm. The limits of detection and quantification for the targeted analytes were in the range of 3.10–12.00 and 10.34–39.83 µg/ml, respectively. The intraday precision was in the range of 1.45–2.06% for migration times and 3.14–4.28% for peak areas, while interday precision was in the range of 2.24–3.20% for migration times and 6.46–7.11% for peak areas, respectively. Spiked recoveries at three levels were in the range of 84.92–101.67%. Results indicated that the bioleaching solution of realgar only exists in organic arsenic, the components were identified to be arsenite and arsenate. Key words: Realgar, bioleaching, Acidithiobacillus ferrooxidans, arsenic species, capillary zone electrophoresis.