Determination of copper, cadmium and lead in biological samples by electrothermal vaporization isotope dilution inductively coupled plasma mass spectrometry

Electrothermal vaporization isotope dilution inductively coupled plasma mass spectrometry (ETV-ID-ICP-MS) was applied to the determination of Cu, Cd and Ph in several biological samples. The isotope ratios for each element in each analytical run were calculated from the peak areas-of each isotope, Various chemical modifiers were tested to obtain the optimum signal of cadmium and palladium was selected, The pyrolytic graphite platforms of the graphite tubes were then pretreated with palladium by three different methods, thermal pretreatment, electroplating and sputtering, and after careful evaluation of the analytical performance of these methods, thermal pretreatment of the platform with Pd before each analysis was selected, The ETV-ID-ICP-MS method was applied to the determination of Cu, Cd and Pb in dogfish liver reference material DOLT-1, dogfish muscle reference material DORM-1 and freeze-dried urine standard reference material NIST SRM 2670. The results-agreed satisfactorily with the certified values.