Separation of Organomercury Species Using Nonaqueous Capillary Electrophoresis Coupled with Sample Stacking and Electrokinetic Injection Techniques

A nonaqueous capillary electrophoresis (NACE) method, 30 mM ammonium acetate in methanol as background electrolyte (BGE), was developed for separation of the organomercury species without complexing reagents. The effects of different solutes and solvents in BGE were studied. Three species of organomercury, methylmercury, ethylmercury and phenylmercury, were separated well and all the number of theoretical plates were over 106. The present NACE method was also coupled with sample stacking and electrokinetic injection techniques to enhance the detection sensitivity. Under the optimum conditions, the limit of detection (S/N = 3) is 18 ng mL−1 and the linear relation range from 40 to 750 ng mL−1 were obtained for methylmercury.