title: Simultaneous on-line preconcentration and determination of trace metals in environmental samples using a modified nanometer-sized alumina packed micro-column by flow injection combined with ICP-OES.
abstract: A novel organic reagent 3-(8-quinolinylazo)-4-hydroxybenzoic acid (QAHBA) was synthesized for chemically modified nanometer-sized alumina, and it was characterized with infrared spectrum and (1)H NMR spectra. By using modified nanometer-sized alumina as micro-column packing material, a new method of flow injection (FI) on-line preconcentration coupled to ICP-OES was developed for simultaneous determination of trace metals (Ag, Pd, Au, Ga, In and Nb) in geological and environmental samples. The effects of pH, sample flow rate, sample volume, elution and interfering ions on the recovery of the analytes have been investigated. Under the optimized operating conditions, the adsorption capacity of the modified nanometer-sized alumina for Ag, Pd, Au, Ga, In and Nb were found to be 5.1, 7.6, 17.7, 15.6, 8.1 and 12.3mgg(-1), respectively. With 4min preconcentration time and 24s elution time, the enrichment factor was 10 and the sample frequency was 10h(-1). The detection limits of this method for Ag, Pd, Au, Ga, In and Nb were 0.12, 0.44, 0.27, 0.19, 0.54 and 0.18mugl(-1), respectively, while the R.S.D.s were 1.6, 2.3, 4.5, 1.6, 1.9 and 1.7% (n=7, c=50ngml(-1)), respectively. The proposed method has been applied to the determination of these trace metals in geological-certified reference materials and natural water samples with satisfactory results.
authors.affiliation: Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
authors.forename: Chaozhang
authors.initials: C
authors.lastname: Hang
authors.forename: Bin
authors.initials: B
authors.lastname: Hu
authors.forename: Zucheng
authors.initials: Z
authors.lastname: Jiang
authors.forename: Nan
authors.initials: N
authors.lastname: Zhang