ICP-AES Determination of Very High Concern Substances Co, As, Cr, Sn and Pb in Rubber and Plastic Products

ICP-AES was applied to the determination of highly concerned substances, including Co, As, Cr, Sn and Pb, in rubber and plastic products. 0.2 g of sample was mixed with 5 mL of HNO3, 2 mL of H2O2 and 1 mL of HBF4 in a digestion vessel, and digested at a temperature of 215 ℃ for 50min. Analytical spectral lines of 230.786, 193.696, 267.716, 189.927 and 220.353 nm were chosen for the determination of the 5 elements respectively. Matrix interference was eliminated by dilution of standard solution with mixture of HNO3, HBF4 and H2O with the ratio of 5 to 2 to 93. Linear relationships between values of emission intensity and mass concentration of the elements were kept in the same range within 5.0 mg·L-1, with detection limits (3s) and lower limits of determination (10s) less than 3 mg·kg-1 and 10 mg·kg-1 respectively. The proposed method was applied to the analysis of 2 CRM′s (EC681K, EC681), giving results in consistency with the certified values. Tests for recovery were made by standard addition method, giving values of recovery in the range of 92.1%-97.4% with RSD′s (n=6) in the range of 1.1%-4.6%.