title: Sol-gel zirconia coating capillary microextraction on-line hyphenated with inductively coupled plasma mass spectrometry for the determination of Cr, Cu, Cd and Pb in biological samples.
abstract: A sol-gel zirconia coating was developed for the preconcentration/separation of trace Cr, Cu, Cd and Pb by capillary microextraction, and the adsorbed analytes were on-line eluted for detection using inductively coupled plasma mass spectrometry (ICP-MS). By immobilizing sol-gel zirconia on the inner surface of a fused-silica capillary, the sol-gel zirconia coating was simply prepared. Its adsorption properties, stability and the factors affecting the adsorption behaviors of Cr, Cu, Cd and Pb were investigated in detail. In the pH range from 7.8 to 10, the zirconia-coated capillary (35 cm x 0.15 mm) is selective towards Cr, Cu, Cd and Pb, and the analyzed ions could be desorbed quantitatively with 0.2 mL of 0.5 mol/L HNO(3) at a rate of 0.2 mL/min. With a consumption of 1.25 mL sample solution, an enrichment factor of 6.25, and detection limits (3sigma) of 9.9 pg/mL Cr, 17.9 pg/mL Cu, 4.5 pg/mL Cd and 3.7 pg/mL Pb were obtained. The precisions for nine replicate measurements of 1 ng/mL Cr, Cu, Cd and Pb were 4.9% Cr, 2.2% Cu, 2.0% Cd and 3.2% Pb (RSD), respectively. The proposed procedure has been applied to the determination of Cr, Cu, Cd and Pb in human urine, which was subjected to microwave-assisted digestion prior to analysis, and the recoveries for these elements were 89.2-101.8%. In order to validate the developed procedure, a NIES No.10-a Rice Flour-Unpolished certified reference material and a BCR No. 184 Bovine Muscle certified reference material were analyzed, and the results are in good agreement with the certified values.
authors.affiliation: Department of Chemistry, Wuhan University, Wuhan 430072, P.R. China.
authors.forename: Yiwei
authors.initials: Y
authors.lastname: Wu
authors.forename: Bin
authors.initials: B
authors.lastname: Hu
authors.forename: Zucheng
authors.initials: Z
authors.lastname: Jiang
authors.forename: Yuqi
authors.initials: Y
authors.lastname: Feng
authors.forename: Peng
authors.initials: P
authors.lastname: Lu
authors.forename: Boyangzi
authors.initials: B
authors.lastname: Li
mesh_terms: D001681:Biological Assay / Q000379:methods*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D046209:Electrophoresis, Microchip / Q000379:methods*; D006801:Humans; D019216:Metals, Heavy / Q000652:urine*; D044367:Phase Transition; D016482:Urinalysis / Q000379:methods*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D020099:Coated Materials, Biocompatible; D019216:Metals, Heavy; D015040:Zirconium; C028541:zirconium oxide