SOME APPLICATIONS OF ISOTOPE ANALYSIS OF LEAD IN FOOD BY ICP-MS

This work explores the relative merits of two approaches, viz., standard additions and isotope dilution analysis (IDA). The latter relies upon the fact that in ICP-MS (Inductively Coupled Plasma-Mass Spectrometer) measurements are made on a mass-by-mass basis and therefore each isotope of an element is measured separately. The accuracy and precision achievable using scanning and peak modes for measurements of lead isotope ratios were studied. If sufficient time and sample materials were available scanning gave better accuracy and precision. Isotope ratios in milk powders and wines of European and Australian origin have been compared. Australian milk powder has a 207/206 lead ratio consistent with that determined for lead in the Broken Hill area of Australia. Isotope dilution analysis (IDA) gave more precise data than standard additions as a means of measuring total lead content in milk powder slurries and wine.