Thallium is a heavy metallic element which is found in the nature as Tl (I) and Tl (III) ions. While being a highly toxic element, thallium has been studied to a much lesser degree than other toxic elements such as lead, cadmium or mercury. The concentration of thallium in the environment is very low, thus an analytical technique featuring high sensitivity and low detection limit is required [1]. Flame atomic absorption spectrometry is a simple and well available technique for determination of various elements in real samples; however, due to the poor sensitivity for thallium, a preconcentration step prior to measurements seems to be necessary. In this study, a thallium (III) ion-imprinted polymer column was used for solid phase extraction of thallium prior to determination by Flame Atomic Absorption Spectrometry. The thallium(III) ion imprinted polymer particles were synthesized via single pot method by dissolving a ternary complex of thallium with 5,7-dichloroquinoline-8-ol and 4-vinylpyridine in acetonitrile (porogen) and copolymerized thermally after addition of methyl methacrylate (monomer) and ethyleneglycoldimethacrylate (crosslinking monomer) in the presence of 2,2-azobisisobutyronitrile (initiator) according to the procedure described elsewhere [2]. Microcolumn was fabricated by using a PTFE (Teflon) tubing (6 cm in length, internal diameter of 3 mm) containing 500 mg for thallium (III) ion-imprinted polymer particles. The end of the tube was fitted with foam to retain the sorbent in the tube. Studies confirmed the reliability of column enrichment/separation using Thallium (III) IIP particles as the sorbent. The main advantages of the method are the simplicity of preparation of microcolumn and the high selectivity and reproducibility for separation, speciation, preconcentration and determination of thallium at trace level. Several parameters such as carrier stream flow rate, nature and flow rate of eluent, sample pH and column length were studied and optimized. Under the optimized experimental conditions, the enrichment factor was 125 and the detection limit (L.O.D.) of 1.5 ng ml−1 was obtained. The relative standard deviation for five replicate analysis of 30 ng ml−1 of thallium (III) was 2.1%. The results for determination of thallium in a certified reference material (unalloyed zinc), spiked tap water and seawater demonstrated the accuracy, recovery and applicability of the presented method.

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