Determination of cadmium,copper,lead,zinc,chromium and nickel in seawater by atomic absorption spectrometry after extraction separation

An atomic absorption spectrometric method for the determination of copper,lead,cadmium,zinc,chromium and nickel in seawater was established.Under the conditions of pH 4.0±0.5and heating in a water bath,with ammonium pyrrolidine dithiocarbamate(APDC)as a chelating agent, copper,lead,cadmium,zinc,chromium and nickel were chelated quantitatively to form chelates which were extracted by MIBK,then zinc was determined by flame atomic absorption spectrometry and the other elements were determined by graphite furnace atomic absorption spectrometry.The results showed that the detection limits for cadmium,chromium,copper,lead,nickel and zinc were 0.04,0.3,0.13,0.2,0.4and 1.0g/L,respectively.Certified reference seawater samples GBW(E) 080040was analyzed,except that nickel had no certified value,the measured results of the other elements were consistent with the certified values.The method was applied to the analysis of seawater from the Pearl River estuary and the Daya Bay,with the relative standard deviations(RSD,n=7)for the measurement results of each element between 2.3%to 6.5%and the recoveries in the range of 94%-105%.