Rapid speciation analysis of mercury by short column capillary electrophoresis on-line coupled with inductively coupled plasma mass spectrometry

A method for mercury high throughput rapid speciation analysis was developed by short column capillary electrophoresis (SC-CE) coupled with inductively coupled plasma mass spectrometry (ICP-MS). A MicroMist nebulizer was employed to increase the nebulization efficiency and a laboratory-made removable SC-CE-ICP-MS interface on the basis of cross design was applied to alleviate buffer contamination of ICP-MS. In less than 60 s, methylmercury (MeHg(i)) and inorganic mercury (Hg(ii)) were separated in a 16 × 75 μm i.d. short fused-silica capillary at 21 kV, while a mixture of 30 mmol L-1 boric acid + 5% (v/v) CH3OH (pH = 8.60) acted as running electrolyte. The precisions (RSD, n = 5) of migration time and peak area for MeHg(i) and Hg(ii) were in the range of 1.4-2.6% and 3.3-3.4%, respectively. The limits of detection (3σ) mercury species were 9.7 μg L-1 and 12.0 μg L-1, respectively. The recoveries for Hg(ii) and MeHg(i) were in the range of 96-107% and 99-105%.