Simultaneous determination of heavy metals in water by high performance liquid chromatography following the solvent extraction of heavy metals as pyrrolidinedithiocarbamato chelates into chloroform.

Abstract

A simple and rapid method for the simultaneous determination of ppb level of lead(II), nickel(II), cobalt(II), copper(II), mercury(II), and bismuth(III) in water was developed, by means of the solvent extraction of the metals as their pyrrolidinedithiocarbamato chelates (PDC-chelates) followed by high performance liquid chromatography (HPLC) of the extract. The HPLC separation of the six (PDC)-metal chelates was performed on a 5 μm (ODS) column(4.6×30 cm, Cosmosil 5 C18), using acetonitrile-water-0.01 M ammonium pyrrolidinedithiocarbamate(69:31:0.15) as the eluent. The eluted (PDC)-metal chelates were detected at 254 nm. The linear calibration curves were obtained in the concentration range of 4-200 ppb for the six metals studied. The correlation coefficient of the calibration curve for each metal was in the range of 0.9985-0.9999. The recovery and the precision of the proposed method were examined for the composite sample containing the above six metals. Although eleven foreign metal ions (Ag(I), Mn(II), Cd(II), Zn(II), Mg(II), Ca(II), Al(III), As(III), Fe(III), Sn(IV), Cr(VI)) were coexisted high recovery and good precision were attained : 98-101 % for the recovery and 0.6-1.6 % for the coefficient of variation. The proposed method was applied to the determination of the above six metals in river water and satisfactory results were obtained as comparable to those by the atomic absorption method.