title: Synthesis and application of imprinted polyvinylimidazole-silica hybrid copolymer for Pb2+ determination by flow-injection thermospray flame furnace atomic absorption spectrometry.
abstract: A novel ion imprinted polyvinylimidazole-silica hybrid copolymer (IIHC) was synthesized and used as a selective solid sorbent for Pb(2+) ions preconcentration using an on-line solid phase extraction (SPE) system coupled to TS-FF-AAS. The ionic hybrid sorbent was prepared using 1-vinylimidazole and 3-(trimethoxysilyl)propylmethacrylate as monomers, Pb(2+) ions as template, tetraethoxysilane as reticulating agent and 2,2'-azobis-isobutyronitrile as initiator. The best on-line SPE conditions concerning sorption behavior, including sample pH (6.46), buffer concentration (9.0 mmol L(-1)), eluent (HNO(3)) concentration (0.5 mol L(-1)) and preconcentration flow rate (4.0 mL min(-1)), were optimized by means of full factorial design and Doehlert matrix. The analytical curve ranged from 2.5 to 65.0 μg L(-1) (r=0.999) with limit of detection of 0.75 μg L(-1); the precision (repeatability) calculated as relative standard deviation (n=10) was 5.0 and 3.6% for Pb(2+) concentration of 10.0 and 60.0 μg L(-1), respectively. From on-line breakthrough curve, column capacity was 3.5 mg g(-1). Preconcentration factor (PF), consumptive index (CI) and concentration efficiency (CE) were 128.0, 0.16 mL and 25.6 min(-1), respectively. The selective performance of the sorbent, based on relative selectivity coefficient, was compared to NIC (non imprinted copolymer) for the binary mixture Pb(2+)/Cd(2+), Pb(2+)/Cu(2+) and Pb(2+)/Zn(2+). The results showed that ion imprinted polyvinylimidazole-silica hybrid polymer had higher selectivity for Pb(2+) than NIC at 64.9, 16.0 and 8.8 folds. The developed method was successfully applied for highly sensitive and selective Pb(2+) determination in different kinds of water samples, parenteral solutions and urine. Accuracy was also assessed by analyzing certified reference fish protein (DORM-3) and marine sediment (MESS-3 and PACS-2) with satisfactory results.
authors: Programa de Pós-Graduação em Química da Universidade Federal de Alfenas, Rua Gabriel Monteiro da Silva 700, Alfenas, MG, CEP 37130-000, Brazil. tarley@uel.br
authors: César Ricardo Teixeira
authors: CR
authors: Tarley
authors: Felipe Nascimento
authors: FN
authors: Andrade
authors: Fernanda Midori
authors: FM
authors: de Oliveira
authors: Marcela Zanetti
authors: MZ
authors: Corazza
authors: Luiz Fernando Mendes
authors: LF
authors: de Azevedo
authors: Mariana Gava
authors: MG
authors: Segatelli
mesh_terms: D004785:Environmental Pollutants / Q000032:analysis* / Q000302:isolation & purification / Q000652:urine; D017022:Flow Injection Analysis; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D007854:Lead / Q000032:analysis* / Q000302:isolation & purification / Q000652:urine; D054802:Molecular Imprinting / Q000379:methods*; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D011145:Polyvinyls / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D052616:Solid Phase Extraction; D013054:Spectrophotometry, Atomic
chemical_list: D004785:Environmental Pollutants; D007093:Imidazoles; D007477:Ions; D011108:Polymers; D011145:Polyvinyls; C072974:polyvinylimidazole; D007854:Lead; D012822:Silicon Dioxide