Determination of tin in biological materials by atomic absorption spectrophotometry and neutron activation analysis

Concentrations of Tin (Sn) were determined in botanical, dietary and biological reference materials (RMs), and in human livers from Japanese and American subjects using atomic absorption spectrophotometry (AAS) and neutron activation analysis (NAA), either in the instrumental mode (INAA) or in the radiochemical mode (RNAA). The mean Sn concentrations (+/- 1 S.D.) found in various RMs are: total diet (NIST SRM-1548) 3.57 +/- 0.52 and 3.61 +/- 0.52 microgram/g by AAS and INAA, respectively; non-fat milk powder (NIST SRM-1549) 2.5 +/- 1.4 ng/g and 1.9 +/- 0.3 ng/g; bovine liver (NBS SRM-1577) 18 +/- 2 and 20 +/- 0.3 ng/g; and citrus leaves (NIST SRM-1542) 0.25 +/- 0.02 and 0.243 +/- 0.006 microgram/g by AAS and RNAA, respectively. These comparisons demonstrate good agreement between the two methods. In apple leaves (NIST SRM-1515) and peach leaves (NIST SRM-1547), the measured concentrations by AAS were 77.1 +/- 20 and 85 +/- 15 ng/g; interferences by 160Tb did not permit an accurate assessment by INAA at this concentration. The Sn results obtained for the American human liver specimens by RNAA ranged from 0.135-0.712 microgram/g wet weight, and the Sn concentrations in Japanese human liver specimens determined by AAS ranged from 0.078-1.122 microgram/g wet weight in 23 individuals. The results from this study show that it is feasible to use INAA/RNAA and AAS in combination to establish recommended values in RMs.