Determination of Inorganic and Total Mercury in Biological Tissues by Electrothermal Vaporization Inductively Coupled Plasma Mass Spectrometry

Abstract

A rapid method for the determination of total and inorganic mercury in biological tissues is presented using electrothermal vaporization inductively coupled plasma mass spectrometry (ETV ICP–MS). Samples were solubilized using tetramethylammonium hydroxide. For the determination of total mercury sample aliquots (10 µl) are dried and vaporized into the plasma. For the determination of inorganic mercury, iodoacetic acid, sodium thiosulfate and acetic acid are added to the sample, cleaving the methylmercury from the tissue. Volatile methylmercury iodide is formed and removed from the ETV as the sample dries, leaving only inorganic mercury to be quantified. A limit of detection of 0.05 µg g ^-1 in solid samples was obtained. National Research Council of Canada reference materials DORM-2 (dogfish muscle), DOLT-2 (dogfish liver) and TORT-2 (lobster hepatopancreas) were used to assess the accuracy of the method.