Analytical Sciences

Simultaneous Determination of Cobalt, Copper and Zinc by Energy Dispersive X-ray Fluorescence Spectrometry after Preconcentration on PAR-loaded Ion-Exchange Resin

Zi-Tao JIANG,* Jimmy C. YU,** and Ho-Yan LIU**

*Department of Food Science and Engineering, Tianjin University of Commerce, Tianjin 300134, P. R. China
**Department of Chemistry and Environmental Science Programme, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong

A sensitive method for the preconcentration and determination of trace amounts of Co, Cu and Zn by energy-dispersive X-ray fluorescence spectrometry (EDXRF) has been developed. The method is based on the fact that 4-(2-pyridylazo)resorcinol (PAR) loaded Dowex anion-exchange resin (PAR-resin) can effectively adsorb Co, Cu and Zn at pH 9.0 to form PAR-metal complexes. The detection limits for Co, Cu and Zn were 1.53, 0.31 and 0.21 ppb, respectively. The precisions for five replicate measurements of the three metals were 3.4, 2.7 and 2.1% RSD, and the calibration curves were linear up to 75 µg with correlation coefficients of 0.9975, 0.9980 and 0.9985, respectively. The method was successfully applied for the simultaneous determination of Co, Cu and Zn in seawater samples at ppb levels.

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