Separation and preconcentration of Pb(II) and Cu(II) ions via carrier element-free coprecipitation using an acetohydrazide derivative

A new method based on the combination of carrier element-free coprecipitation and flame atomic absorption spectrometric determination has been investigated for simultaneous separation and preconcentration of Pb(II) and Cu(II) ions in some environmental solid and liquid samples. The 2-f3-(4-methylbenzyl)-4-[2-(1H-indol-3-yl)ethyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-ylg -N'-(phenylmethylene) acetohydrazide (MITA) was utilized as an organic coprecipitating agent without using a carrier element for coprecipitation of the analyte ions. The effects of experimental conditions including aqueous solution pH, MITA quantity, sample volume, standing time, and centrifugation rate and time were investigated in detail and optimized. The influences of some foreign ions were also evaluated on the quantitative recoveries of the analyte ions. The preconcentration factors were 125 for both analyte ions. The detection limits were 1.32 μgL-1 and 0.47 μg L-1 for Pb(II) and Cu(II) ions, respectively, and the relative standard deviations (RSDs) were lower than 4% for both analyte ions. After the accuracy of the method was checked, it was applied to sea and stream water as liquid samples and waste tea and tobacco as solid samples to determine the levels of Pb(II) and Cu(II) ions.