DETERMINATION OF TRACE-ELEMENTS IN BIOLOGICAL-MATERIALS BY ETV-ICP-MSAFTER DISSOLUTION OR SLURRY FORMATION WITH TETRAMETHYLAMMONIUM HYDROXIDE

A method to prepare biological samples to be analysed by electrotherma l vaporization inductively coupled plasma mass spectrometry is propose d. A solution or slurry was formed by mixing a sample aliquot, 20-100 mg, with a small volume, 10-200 mu L, of a 25% m/v tetramethylammonium hydroxide solution. For animal tissues, complete dissolution was obta ined, whereas for the plant and whole egg materials, slurries were obt ained. The slurries were stirred manually, every three readings, in th e instrument. The pyrolysis and atomization temperatures were optimize d, using Pd as a carrier-modifier for As, Se, Te, Ag, Cr, Cu, V, Ni, M n, Co and Cd. An Ir-coated tube was used for Pb, Sb, Sn and Bi. Extern al calibration was used preferentialy, but in some instances, the anal yte additions method was employed. Good results were obtained for four certified reference materials. However, Cr and Cd could not be determ ined in the bovine muscle sample owing to spectral interferences and m atrix effects, respectively.