Polymeric ion-imprinted nanoparticles for mercury speciation in surface waters

Selective sorption and enrichment of Hg(II) were achieved by polymeric ion-imprinted nanoparticles, prepared by copolymerization of methacrylic acid (functional monomer), trimethylolpropane trimethacrylate (cross-linking agent), 2,2′-azo-bis-isobutyronitrile (initiator) and Hg(II) complexes with chelating agent 1-pyrrolidinedithiocarboxylic acid. The particles were characterized for their morphology, composition and structure by using AFM, FTIR and elemental analysis. Extraction efficiency and selectivity of ion imprinted sorbent toward Hg(II) were studied by batch procedures. Two distinct adsorption sites were identified on the surface of the polymeric nanoparticles through Scatchard analysis performed. Adsorption process was characterized by Langmuir isotherm model. Solid phase extraction procedure was developed for Hg speciation and determination in surface waters. The accuracy of the proposed speciation scheme was confirmed by the analysis of certified reference material. Limits of quantification achieved (0.015 μg L− 1 for Hg(II) and 0.02 μg L− 1 for methylmercury) and RSD values (7-12% for both species) completely satisfy requirements of European legislation for monitoring of surface waters.