title: Analytical performance of a lab-made concomitant metal analyzer to generate volatile species of Ag, Au, Cd, Cu, Ni, Sn and Zn using 8-hydroxyquinoline as a reaction media.
abstract: This study evaluated the main parameters affecting Ag, Au, Cd, Cu, Ni, Sn and Zn vapor generation using a lab-made concomitant metal analyzer (CMA) as a reaction chamber and gas-liquid separator. The modifier used in the reaction media was 8-hydroxyquinoline, and Inductively-Coupled Plasma Optical Emission Spectrometry was used as detection technique. The performance of the lab-made concomitant analyzer was compared with the performance of a continuous flow gas-liquid separator and of a cyclonic spray chamber. Standards were prepared in acid media and included 1 mg L(-1) of Co as a catalyzer. The optimum concentrations of the reagents in the standards were: 450 mg L(-1) of 8-hydroxyquinoline and 0.4 M nitric acid. The optimum concentration of sodium borohydride to generate the vapors was 2.25% (w/v) (prepared in 0.4% (w/v) NaOH). The volatile species were swept from the CMA to the torch by an argon flow of 0.6 mL min(-1). The use of the CMA led to an improvement of the detection limits for some elements compared to conventional nebulization: 1.1 μg L(-1) for Ag, 7.0 μg L(-1) for Au and 4.3 μg L(-1) for Sn. The limit of detection for Cu was 1.4 μg L(-1) and for Ni 22.5 μg L(-1). The direct mixing of the reagents on the spray chamber was not effective for Cd and Zn; a deviation of the linearity was observed for these elements.
authors.affiliation: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida de las Ciencias s/n, E-15782, Santiago de Compostela, Spain.
authors.forename: Julia
authors.initials: J
authors.lastname: Villanueva-Alonso
authors.forename: Elena
authors.initials: E
authors.lastname: Peña-Vázquez
authors.forename: Pilar
authors.initials: P
authors.lastname: Bermejo-Barrera
mesh_terms: D002104:Cadmium / Q000032:analysis / Q000737:chemistry; D003300:Copper / Q000032:analysis / Q000737:chemistry; D006046:Gold / Q000032:analysis / Q000737:chemistry; D007753:Laboratories; D057230:Limit of Detection; D019216:Metals, Heavy / Q000032:analysis* / Q000737:chemistry*; D009532:Nickel / Q000032:analysis / Q000737:chemistry; D015125:Oxyquinoline / Q000737:chemistry*; D012834:Silver / Q000032:analysis / Q000737:chemistry; D014001:Tin / Q000032:analysis / Q000737:chemistry; D014835:Volatilization; D015032:Zinc / Q000032:analysis / Q000737:chemistry
chemical_list: D019216:Metals, Heavy; D002104:Cadmium; D012834:Silver; D015125:Oxyquinoline; D014001:Tin; D006046:Gold; D003300:Copper; D009532:Nickel; D015032:Zinc