Development of a new HPLC method for the determination of inorganic and methylmercury in biological samples with ICP-MS detection

Abstract

In the present work a new HPLC method for the determination of mercury species in biological samples with ICP-MS detection was developed. Separation of inorganic (Hg²⁺) and methylmercury (CH₃Hg⁺) was accomplished on a Hamilton PRP-X200 polymer-based cation-exchange column with a mobile phase of 50 mmol l⁻¹ pyridine, 0.5% w/w L-cysteine and 5% v/w MeOH, at pH 2, within 8 min. The influence of chromatographic parameters, such as pH, salt concentration, organic modifier, and ion-pair reagent on the retention behaviour was evaluated. Based on peak areas, the experimental detection limits for inorganic and methylmercury were 0.05 and 0.08 μg Hg l⁻¹, which corresponds to an absolute detection limit of 1.0 and 1.6 pg of mercury (20 μl injection volume). The liquid chromatographic method was successfully applied to the determination of inorganic and methylmercury in the two certified reference materials DORM-2 and DOLT-3, after a rapid and simple sample preparation procedure using hydrochloric acid.