Pretreatment method for determination of trace elements in seawater using solid phase extraction column packed with polyamino-polycarboxylic acid type chelating resin

A pretreatment method of Al, Mn, Fe, Ni, Cu, Zn, Mo, Cd, Pb, and U in seawater has been investigated using the solid phase extraction column packed with polyamino-polycarboxylic acid type chelating resin. The dependence of pH on the recovery differed in each analytes. However, all analytes were simultaneously extracted at pH 5.5. Hence the optimum condition was decided at pH 5.5. Na, K, Ca, and Mg, which are major components in the seawater were not extracted at pH 7 and below. After the column was cleaned with 10 ml of pure water, the optimum concentration of nitric acid as eluate was 3 M. The analytes concentration in standard reference materials (Seawater NRC-CNRC, CASS-4) pretreated by the presented method was measured with the ion source mass spectrometer and the analytical values were well agreed with the certified values and the reference values without the interference of major components. Moreover, in the analysis of the analytes in the coastal sea water sample, a high recovery of 93 107% was obtained.