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

Abstract

• Presentation of a new analytical method for mercury separation. • Highly selective separation and fast determination of hazardous mercury ion. • Determination of Hg 2+ ion in water and hair samples with acceptable accuracy and precision. • On-line determination of mercury ion based on Hg-IIP NPs through FIA. This work reports a new analytical method for the preconcentration and determination of Hg 2+ ions based on flow injection technique coupled with a solid phase extraction process. Hg 2+ ion imprinted polymeric (IIP) nanomaterials were prepared by using the bulk polymerization procedure, and then applied as an efficient solid phase extractor for selective separation of Hg 2+ 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 × 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 Hg 2+ 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 Hg 2+ 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 σ ) of the method for eight replicates at optimum pH, were evaluated as 4.2% and 0.036 ng mL −1 , respectively. The IIP sorbent show an excellent selectivity for Hg 2+ ion over other metal ions and was successfully applied to the selective extraction and determination of Hg 2+ ion in water and human hair samples.