Intercomparison 0923: pH, Cond, HCO3, NO3-N, Cl, SO4, Ca, Mg, Na, K, TOC, Al, Fe, Mn, Cd, Pb, Cu, Ni, and Zn (ICP Waters report 98/2009)

Abstract

72 laboratories received samples for the intercomparison 0923, and 68 laboratories in 29 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 zinc, magnesium and sodium, with 90, 88 and 88 % acceptable results, respectively. Low percentage of acceptable results was observed for copper with only 37 % acceptable results, due to the low concentrations in the samples used. 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.