Determination of Pt in digested animal plasma and tissues using High Resolution Inductively Coupled Plasma HR-ICP-MS. Samples were measured in Low Resolution LR mode considering Pt(194), Pt(195), Pt(196), and Pt(198). In order to minimize the matrix effect, calibration standards were prepared with samples of pig tissues free of Pt and treated in the same way as the samples to be analyzed containing platinum. Under theses experimental conditions Pt analytical determination results are reliable. Matrix effect and Pt determination using HR-ICP-MS will be discussed.