title: On-line chemical vapour generation of cadmium in the presence of hexacyanochromate(III) for determination by inductively coupled plasma mass spectrometry (ICP-MS).
abstract: A vapour generation (VG) procedure has been described for determination of Cd by ICP-MS. Volatile species of Cd were generated on-line by interacting acidic sample solution containing potassium hexacyanochromate(III), K3Cr(CN)6, with sodium borohydride (NaBH4). The hexacyanochromate(III) complex was generated on-line by reacting 0.04 mol L-1chromium(III) nitrate and 0.16 mol L-1potassium cyanide (KCN) solutions in water. The resulting suspension of chromium(III) hydroxide, Cr(OH)3, was fed continuously to acidic stream of sample solution in the presence of excess KCN. The experimental conditions were optimized for effective generation of volatile species of Cd. Optimum signals were obtained from reaction of sample solutions in 4% v/v HCl with 2% m/v NaBH4solution. Presence of K3Cr(CN)6improved the efficiency of Cd vapour generation substantially affording 15-fold higher sensitivity. This phenomenon was thought to occur through formation of reactive intermediates evolved from interaction of [Cr(CN)6]3-with NaBH4that react with Cd(II) to increase the yield volatile Cd species. Under the optimum conditions, no significant interferences were observed from the transition metals, including Cu and Ni, up to 1.0 μg mL-1levels. Among the hydride forming elements, Bi, Pb, Sb and Sn depressed the signals above 0.1 μg mL-1. The detection limits (3s) were 6.2 and 5.2 ng L-1for110Cd and111Cd isotopes, respectively. The method was successfully applied to determination of Cd by ICP-MS in several certified reference materials, including Nearshore seawater (CASS-4), Bone ash (SRM 1400), Dogfish liver (DOLT-4) and Mussel tissue (SRM 2976).
authors.affiliation: Jackson State University, Department of Chemistry and Biochemistry, Jackson, MS 39217 USA. Tel: 01 (601)979-2072; ; Erciyes University, Faculty of Pharmacy, Department of Analytical of Chemistry, 38039 Kayseri, Turkey.
authors.forename: Vedat
authors.initials: V
authors.lastname: Yilmaz
authors.forename: Lakeysha
authors.initials: L
authors.lastname: Rose
authors.forename: Zikri
authors.initials: Z
authors.lastname: Arslan
authors.forename: Maria D
authors.initials: MD
authors.lastname: Little