Determination of Physiological Palladium, Platinum, Iridium and Gold Levels in Human Blood Using Double Focusing Magnetic Sector Field Inductively Coupled Plasma Mass Spectrometry

Abstract

A procedure is described for the determination of Pd, Ir, Pt and Au in human blood at environmental concentrations based on double focusing magnetic sector field ICP-MS. It is shown that the practical detection limits in such complex matrices are not essentially limited by instrumental capabilities, but are mainly a result of blank values and spectral interferences. Feasible ways are shown to reduce these blanks and interferences. Ultraviolet photolysis was found to be advantageous over mineral acid digestion techniques, because minimal reagent addition is required. Additional sub-boiling distillation of the commercially available ultrapure nitric acid, working in a clean-air laboratory and a skillful cleaning of all materials resulted in a further reduction of blanks. With the exception of Au, detection limits in blood samples were found to be well below 1 ng l ^-1 . Taking into account a dilution factor of 22.4 the detection limits related to the final solution were between 0.01 and 0.02 ng l ^-1 . The Pd, Ir, Pt and Au were detectable in the blood samples of all seven unexposed volunteers.