On-line flow injection solid phase extraction using imprinted polymeric nanobeads for the preconcentration and determination of mercury ions

This work reports a new analytical method for the preconcentration and determination of Hg2+ ions based on flow injection technique coupled with a solid phase extraction process. Hg2+ ion imprinted polymeric (HP) nanomaterials were prepared by using the bulk polymerization procedure, and then applied as an efficient solid phase extractor for selective separation of Hg2+ ions. The prepared sorbent was characterized using FT-IR spectroscopy, scanning electron microscopy (SEM), various thermal analysis methods, and Brunauer, Emmett, and Teller adsorption isotherm analysis (BET). According to the results, surface area, pore volume and average pore diameter of the prepared Hg-IIP were found to be 3.05 x 10(2) m(2) g(-1), 1.07 cm(3) g(-1) and 15.33 nm, respectively. In the sorption studies, after preconcentration and loading of Hg2+ ions on the IIP sorbent, its mercury content was eluted by suitable solution and then determined photometrically, by a designed on-line recording process coupled with a flow injection procedure. The influence of the mercury concentration, preconcentration and elution times, nature, volume, and concentration of the eluent, pH, and flow rate of the solution and eluent on the polymer affinity has been investigated. Bound Hg2+ ions can be eluted with 5 mL of nitric acid 1.0 mol L-1 and then treated with diphenylthiocarbazone, finally quantified photometrically at 485 nm. The relative standard deviation and detection limit (3 sigma) of the method for eight replicates at optimum pH, were evaluated as 4.2% and 0.036 ng mL(-1), respectively. The HP sorbent show an excellent selectivity for Hg2+ ion over other metal ions and was successfully applied to the selective extraction and determination of Hg2+ ion in water and human hair samples. (C) 2014 Elsevier B.V. All rights reserved.