Multielement Analysis of Tin-Lead Solder by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES)

Abstract

The quality control of the chemical composition of tin-lead solder is one of the routine analytical applications in the department of inorganic chemistry. A rapid and reliable method of analysis was established by use of the inductively coupled plasma atomic emission spectrometry (ICP-AES), which allows multielement quantitative determination of the impurities below criteria levels, as well as the determination of the major elements in solder. The most difficult part of the method remains the solder disintegration, as the dissolution of tin and lead together is a difficult chemical procedure. The samples were dissolved in a mixture of HCl and HNO₃. A 4 g/l solder solution was found to be suitable for analyzing traces of Ag, Al, As, Au, Bi, Cd, Cu, Fe, In, Ni, Sb, and Zn with a better precision and accuracy compared to the combined spark-ICP AES method used previously. The results for Sn and Pb obtained with dilute solutions were in good agreement with those obtained by the wet chemical methods. Spectral interferences from Sn and Pb, as well as matrix effects were found to be negligible for most of the trace elements. The reliability of the analytical results achieved in routine programs was proved with commercially certified reference materials. The discrepancies found for some elements between the certified mean values and the ICP results are discussed.