Simultaneous determination of nickel, lead, cadmium and mercury in water by RP-HPLC followed by on-line column enrichment

A new method for the simultaneous determination of four heavy metal ions, nickel, lead, cadmium and mercury ions as metal-tetra-(2-aminophenyl)-porphyrin (T 2APP) chelates was developed using reversed-phase high performance liquid chromatography (RP-HPLC) equipped with a photodiode array detector and combined with an on-line enrichment technique. The detection limits (S/N=3) of nickel, lead, cadmium and mercury are 3.5 ng/L, 2.5 ng/L, 3.0 ng/L and 3.0 ng/L, respectively. This method has been applied to the determination of nickel, lead, cadmium and mercury ions in water with good results.