title: Application of chitosan and its N-heterocyclic derivatives for preconcentration of noble metal ions and their determination using atomic absorption spectrometry.
abstract: Chitosan and its N-heterocyclic derivatives N-2-(2-pyridyl)ethylchitosan (2-PEC), N-2-(4-pyridyl) ethylchitosan (4-PEC), and N-(5-methyl-4-imidazolyl) methylchitosan (IMC) have been applied in group preconcentration of gold, platinum, and palladium for subsequent determination by atomic absorption spectroscopy (AAS) in solutions with high background concentrations of iron and sodium ions. It has been shown that the sorption mechanism, which was elucidated by XPS, significantly influences the sorption capacity of materials, the efficiency of metal ions elution after preconcentration, and, as a result, the accuracy of metal determination by AAS. We have shown that native chitosan was not suitable for preconcentration of Au(III), if the elution step was used as a part of the analysis scheme. The group preconcentration of Au(III), Pd(II), and Pt(IV) with subsequent quantitative elution using 0.1M HCl/1M thiourea solution was possible only on IMC and 4-PEC. Application of IMC for analysis of the national standard quartz ore sample proved that gold could be accurately determined after preconcentration/elution with the recovery above 80%.
authors.affiliation: Institute of Chemistry, Far East Branch of RAS, 159, Prosp. 100-letiya Vladivostoka, Vladivostok 690022, Russia.
authors.forename: Yu A
authors.initials: YA
authors.lastname: Azarova
authors.affiliation: I. Ya. Postovsky Institute of Organic Synthesis, Ural Branch of RAS, 20, S. Kovalevskoy Str., Yekaterinburg 620990, Russia.
authors.forename: A V
authors.initials: AV
authors.lastname: Pestov
authors.affiliation: Institute of Chemistry, Far East Branch of RAS, 159, Prosp. 100-letiya Vladivostoka, Vladivostok 690022, Russia; Far Eastern Federal University, 8, Sukhanova St., Vladivostok 690950, Russia.
authors.forename: A Yu
authors.initials: AY
authors.lastname: Ustinov
authors.affiliation: Institute of Chemistry, Far East Branch of RAS, 159, Prosp. 100-letiya Vladivostoka, Vladivostok 690022, Russia. Electronic address: sbratska@ich.dvo.ru.
authors.forename: S Yu
authors.initials: SY
authors.lastname: Bratskaya
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D019216:Metals, Heavy / Q000032:analysis* / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry; D013054:Spectrophotometry, Atomic / Q000379:methods*
chemical_list: D006571:Heterocyclic Compounds; D007093:Imidazoles; D019216:Metals, Heavy; D011725:Pyridines; C029899:imidazole; D048271:Chitosan; D007501:Iron; C023666:pyridine
keywords: Atomic absorption spectrometry; Chelates; Chitosan; Detection limits; Gold(III) reduction; Metal ionspreconcentration