An off-line chelation system combined with ICP-MS technique was developed for the quantitative determination of trace elements in seawater,namely V,Co,Ni,Cu,Zn,Mo,Cd,Pb,U and rare earth elements（REEs）.The system was built based on an ion chromatography equipped with MetPac CC-1 chelation columns which had a strong selective chelation to these target elements within a pH range 5.2—5.6.Acidified seawater samples and NH4Ac（2 mol/L） were blended to meet suitable pH before being injected into the chelation column,thus target elements were retained while alkali and alkaline metals were excluded.Then chelated elements were eluted by HNO3（1 mol/L） and samples were collected for ICP-MS analysis.Varying the ratio of input（gen.200 mL） to output（gen.5 mL）,the target elements which were concentrated as 40 times as their concentrations were far beyond instrumental quantification limits.At last,a certificated seawater CASS-4 was introduced and our detected values were in good agreement with those certified values.
