Intercomparison 1024: pH, Cond, HCO3, NO3-N, CI, SO4, Ca, Mg, Na, K, TOC, A1, Fe, Mn, Cd, Pb, Cu, Ni, and Zn (ICP Waters report 102/2010)

Abstract

75 laboratories received samples for the intercomparison 1024, and 65 laboratories in 25 countries submitted results. Two sample sets were used, one for the determination of major ions, and one for heavy metals. Based on the general target accuracy of 20 %, 75 % of the overall results were considered as acceptable. The best results were reported for the analytical variables sodium, cadmium and manganese, with 93, 88 and 85 % acceptable results, respectively. Low percentage of acceptable results was observed for pH with only 49 % acceptable results, and copper with 51 % acceptable results. Harmonization of the analytical methods used, and the practical procedures followed, may probably be the most important way to improve the comparability for these parameters.