Analytical Sciences

Abstract − Analytical Sciences, 23(10), 1203 (2007).

Synthesis of Cross-linked Chitosan Modified with the Glycine Moiety for the Collection/Concentration of Bismuth in Aquatic Samples for ICP-MS Determination
Koji OSHITA,* Osamu NOGUCHI,** Mitsuko OSHIMA,** and Shoji MOTOMIZU**
*Department of International Conservation Studies for Cultural Properties, Faculty of Cultural Properties, Kibi International University, 8 Iga-machi, Takahashi, Okayama 716-8508, Japan
**Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushimanaka, Okayama 700-8530, Japan
A chelating resin, cross-linked chitosan modified with the glycine moiety (glycine-type chitosan resin), was developed for the collection and concentration of bismuth in aquatic samples for ICP-MS measurements. The adsorption behavior of bismuth and 55 elements on glycine-type chitosan resin was systematically examined by passing a sample solution containing 56 elements through a mini-column packed with the resin (wet volume; 1 ml). After eluting the elements adsorbed on the resin with nitric acid, the eluates were measured by ICP-MS. The glycine-type chitosan resin could adsorb several cations by a chelating mechanism and several oxoanions by an anion-exchange mechanism. Especially, the resin could adsorb almost 100% Bi(III) over a wide pH region from pH 2 to 6. Bismuth could be strongly adsorbed at pH 3, and eluted quantitatively with 10 ml of 3 M nitric acid. A column pretreatment method with the glycine-type chitosan resin was used prior to removal of high concentrations of matrices in a seawater sample and the preconcentration of trace bismuth in river water samples for ICP-MS measurements. The column pretreatment method was also applied to the determination of bismuth in real samples by ICP-MS. The LOD of bismuth was 0.1 pg ml-1 by 10-fold column preconcentration for ICP-MS measurements. The analytical results for bismuth in sea and river water samples by ICP-MS were 22.9 ± 0.5 pg ml-1 (RSD, 2.2%) and 2.08 ± 0.05 pg ml-1 (RSD, 2.4%), respectively.