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A mineralization and determination method for total iodine in nutritional and biological samples is described. Combustion of the sample in an oxygen stream is followed by collection of the combustion products in a 5% water-soluble tertiary amine solution. Iodine is determined by inductively coupled plasma mass spectrometry. The accuracy and precision of the quantitative iodine analysis using standard addition is better than +/- 10%. A semi-quantitative analysis of four standard reference materials is evaluated. Owing to the presence of low-level iodine contaminant in the blank solution, the determination limit of the method is +/- 10 micrograms kg-1. Good agreement with certified iodine values is obtained for six reference materials. The use of the tertiary amine matrix solution permits the simultaneous determination of iodine and other trace metals of biological and toxicological importance, including Mn, Co, Ni, Cu, Zn, Rb, Cd, and Pb.

The combination of liquid chromatography and inductively coupled plasma/mass spectrometry (ICP/MS) was employed in an exploratory study to determine lead and other trace element species in blood components. In human blood serum, lead was found in at least three molecular weight fractions at greater than 600,000, 260,000, and 140,000. The major part of lead was coincident with the main copper signal at a molecular weight of 140,000. This fraction, binding both copper and lead, was proven to be ceruloplasmin by the application of an immunological reaction prior to chromatographic separation. In rat serum, lead could be detected in four fractions with molecular weights of greater than 600,000, 400,000, 145,000, and 11,000. In human red blood cell hemolysate, the major fraction of lead was found at 250,000, with minor fractions at 140,000 and at 30,000 together with iron in hemoglobin and zinc in carbonic anhydrase. In rat red blood cell hemolysate, lead was detected at greater than 600,000, 145,000, 30,000, and 11,000. Lead isotope ratios were determined in lead binding protein fractions with a precision of +/- 10%. The detection limit for lead in protein fractions was 0.15 micrograms.L-1.