Platinum determination in nutrient plants by inductively coupled plasma mass spectrometry with special respect to the hafnium oxide interference

Platinum, emitted from automobile exhaust catalysts, is mainly oxidised in a humic soil, as described previously [1]. An experiment with nutrient plants was carried out to elucidate the bioavailability and accumulation of these platinum containing species. The plants [Allium cepa L. (Weiss, Fruhling), Rephanus sativus L. (Riesenbutter), Vicia faba L. (Hedin, Herzfreya), Zea mays L. (Delis) and Solanum tuberosum L. (Selma)] were grown under natural conditions. For mass balances all ways of platinum transport into and out of the system were monitored during the growing period. Plants growing in untreated soil took up less than 1% of the platinum naturally present in the soil [0.15 +/- 0.11 mu g kg(-1) (78%)]. Plants growing in soil treated with a platinum containing tunnel dust took up slightly more platinum, The comparison of ICP-quadrupole-MS results with those obtained by a double focusing magnetic sector ICP-MS showed a strong dependence of the platinum concentration on the Hf-content in the sample. An evaluation method for the correction of the Hf-influence for ICP-quadrupole-MS is presented.