Determination of trace elements in biological materials by ETV-ICP-MS after dissolution or slurry formation with tetramethylammonium hydroxide

Abstract

A method to prepare biological samples to be analysed by electrothermal vaporization inductively coupled plasma mass spectrometry is proposed. A solution or slurry was formed by mixing a sample aliquot, 20–100 mg, with a small volume, 10–200 µL, of a 25% m/v tetramethylammonium hydroxide solution. For animal tissues, complete dissolution was obtained, whereas for the plant and whole egg materials, slurries were obtained. The slurries were stirred manually, every three readings, in the instrument. The pyrolysis and atomization temperatures were optimized, using Pd as a carrier–modifier for As, Se, Te, Ag, Cr, Cu, V, Ni, Mn, Co and Cd. An Ir-coated tube was used for Pb, Sb, Sn and Bi. External calibration was used preferentialy, but in some instances, the analyte additions method was employed. Good results were obtained for four certified reference materials. However, Cr and Cd could not be determined in the bovine muscle sample owing to spectral interferences and matrix effects, respectively.