Interlaboratory collaborative analysis of rainwater reference material

The results of an interlaboratory collaborative analysis of real-time rainwater sample obtained at the Geochemical Laboratory of National Geophysical Research Institute, Hyderabad, are presented. Estimation of eleven important toxic and trace metals (Al, V, Mn, Fe, Ni, Co, Cu, Zn, As, Cd and Pb) by inductively coupled plasma mass spectrometry (ICP-MS) is compared with reference and informative values provided by the organizer. Depending upon the Z-scores calculated, the fitness of the data for either 'pure geochemistry' or 'applied geochemistry' was assessed. An overview of Z-score results indicated that the data for Al, Mn, Ni, Co, Cu, Zn, Cd and Pb fell within the −2 < Z < 2 range, which included majority of the toxic and trace metals used in several problems dealing with atmospheric deposition. These results help to further investigate the analytical discrepancies observed in the data, optimize necessary aspects and minimize the interference effects caused during analysis.