Trace analysis of platinum in biological samples: a comparison between sector field ICP-MS and adsorptive cathodic stripping voltammetry following different digestion procedures

A study was carried out to analyse Pt trace levels in fish liver and mussel soft tissue, using two different analytical techniques. Sector field inductively coupled plasma mass spectrometry (SF-ICP-MS) combined with microwave digestion was compared with adsorptive cathodic stripping voltammetry (ACSV) following high pressure ashing (HPA). A microwave digestion procedure for animal tissue was developed, using HNO3 and H2O2. The procedural detection limit of Pt with SF-ICP-MS in combination with this digestion procedure was 2.4ng/l in the solution. The subsequent detection limit considering 300mg liver tissue (wet weight) was found to be 200pg/g Pt. In comparison, the detection power of ACSV after HPA digestion was about 20 times more sensitive. The higher procedural detection limit of the ICP-MS-based method is due to the high dilution necessary to reduce acid concentration. Nevertheless, the results of both analytical methods differed between 16 and 30% for Pt concentrations below 1ng/g, and were almost identical (2-10% deviation) above this value. The Pt levels in the animal tissues analysed ranged between 0.1 and 2.3ng/g.