Determination of Ni, Cu and Hg by flow injection preconcentration coupled with HPLC

A home designed pressure tight preconcentration column combined with the HP LC six-port valve was used to interface the FI sorbent extraction preconcen tration system and HPLC, Based on this system, a method for determination o f trace amount of Ni, Cu and Hg in water samples after on-line derivatizati on and preconcentration as their diethyldithiocarbamate complexes has been developed, The sensitivity and selectivity can be further improved by using time programming for absorption measurement. The detection limit 0.16 mu g /L, 0.41 mu g/L and 1.1 mu g/L, and the relativity standard deviation, 3.6% , 4.5% and 3.9%, were found for Ni(II), Cu(II) and Hg(II), respectively.