EVALUATION OF A FLOW-INJECTION SYSTEM COMBINED WITH AN INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETER WITH THERMOSPRAY NEBULIZATION FOR THE DETERMINATION OF TRACE LEVELS OF PLATINUM

In this paper the coupling of a flow injection system to an inductivel y coupled plasma mass spectrometer using thermospray nebulization for the determination of platinum is evaluated. The results are compared w ith pneumatic nebulization. The flow injection system provides the pos sibility of on-line sample dilution and on-line standardization. A com parative study was made between on-line isotope dilution, on-line stan dard additions and external calibration emphasizing accuracy, precisio n and flexibility of the method. Several parameters of thermospray and flow injection were evaluated. Sensitivity, background and detection limits were studied as well as the peak integration method to be used with the now injection system. The detection limits, using flow inject ion (200 mu l loop) and partial integration of the peak, were in the r ange of 25 ng/l (5 pg absolute) and 8 ng/l (2 pg absolute) for pneumat ic and thermospray nebulization, respectively. The optimized procedure was used for the analysis of Pt in corn leaves, mouse liver and a Ca- 3(PO4)(2) matrix.