Determination of Five Heavy Metal Ions in Environmental Samples by a Rapid High-Performance Liquid Chromatography

Abstract

A new method for the simultaneous determination of five heavy metal ions in water and food by a rapid high-performance liquid chromatography was developed. The lead, cadmium, mercury, nickel and zinc ions were pre-column derivatized with 2-(2-quinolinylazo)-resorcin (QAR) to form coloured chelates, then the Pb-QAR, Cd-QAR, Hg-QAR, Ni-QAR and Zn-QAR chelates were enriched by solid phase extraction with C_I8 cartridge. The enrichment factor of 100 was achieved by eluting the retained chelates from the cartridge with tetrahydrofuran. These chelates were separated on a Zorbax stable bound rapid analysis column (4.6 x 50 mm, 1.8μm) with 65% methanol (containing 0.05 mol/L of pH = 8.5 pyrrolidine-acetic acid buffer salt and 0.01 mol/L of CTMAB) as mobile phase at a flow rate of 2.0 mL/min and detected with a photodiode array detector from 450-600 nm. The Pb-QAR, Cd-QAR, Hg-QAR, Ni-QAR and Zn-QAR chelates were separated completely within 2.0 min. The detection limits of lead, cadmium, mercury, nickel and zinc are 1.5, 1.2, 1.0, 1.8 and 2.0 ng/L, respectively in the original samples. This method was applied to the determination of the five metal ions in water and food samples with good results.