INFLUENCE OF SAMPLE PRETREATMENT ON THE DETERMINATION OF TRACE-ELEMENTS IN URINE BY QUADRUPOLE AND MAGNETIC-SECTOR FIELD INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

An investigation was carried out to explore further the analytical cap abilities of quadrupole and magnetic sector field inductively coupled plasma mass spectrometry (ICP-MS) in conjunction with ultrasonic nebul ization (UN) for the reliable determination in human urine of nine pot entially toxic and/or environmentally relevant trace elements, namely Cd, Co, Cr, Ni, Pb, Rb, Sb, Se and V. For the quantification of Cr, Ni and V magnetic sector field ICP-MS was used in the medium resolution mode (m/Delta m=3000) to separate the signal of the analyte from sever e polyatomic interferences caused by high concentrations of bulk eleme nts (C, Ca and Cl). The detection power afforded by quadrupole ICP-MS, on the other hand, was adequate for the reliable determination of Cd, Co, Pb, Rb, Sb and Se. Three different sample pre-treatment steps, na mely dilution of urine with high-purity water, UV irradiation and micr owave digestion with concentrated HNO3 and H2O2, were investigated in detail to clarify two hey issues, i.e., first, the performance, accura cy and reproducibility of the two ICP-MS systems under different matri x loads of the plasma and, second, the actual concentrations of trace elements in the urine sediment.