title: Micro solid phase spectrophotometry in a sequential injection lab-on-valve platform for cadmium, zinc, and copper determination in freshwaters.
abstract: This work describes the development of a solid phase spectrophotometry method in a μSI-LOV system for cadmium, zinc, and copper determination in freshwaters. NTA (Nitrilotriacetic acid) beads with 60-160 μm diameter were packed in the flow cell of the LOV for a μSPE column of 1 cm length. The spectrophotometric determination is based on the colourimetric reaction between dithizone and the target metals, previously retained on NTA resin. The absorbance of the coloured product formed is measured, at 550 nm, on the surface of the NTA resin beads in a solid phase spectrophotometry approach. The developed method presented preconcentration factors in the range of 11-21 for the metal ions. A LOD of 0.23 μg L(-1) for cadmium, 2.39 μg L(-1) for zinc, and 0.11 μg L(-1) for copper and a sampling rate of 12, 13, and 15 h(-1) for cadmium, zinc, and copper were obtained, respectively. The proposed method was successfully applied to freshwater samples.
authors.affiliation: CBQF-Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal.
authors.forename: Inês C
authors.initials: IC
authors.lastname: Santos
authors.affiliation: CBQF-Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal; Laboratório de Hidrobiologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto, Portugal.
authors.forename: Raquel B R
authors.initials: RB
authors.lastname: Mesquita
authors.affiliation: CBQF-Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal. Electronic address: arangel@porto.ucp.pt.
authors.forename: António O S S
authors.initials: AO
authors.lastname: Rangel
mesh_terms: D002104:Cadmium / Q000032:analysis*; D003300:Copper / Q000032:analysis*; D004784:Environmental Monitoring / Q000295:instrumentation; D004867:Equipment Design; D005618:Fresh Water / Q000032:analysis*; D057230:Limit of Detection; D013053:Spectrophotometry / Q000295:instrumentation*; D015032:Zinc / Q000032:analysis*
chemical_list: D002104:Cadmium; D003300:Copper; D015032:Zinc
keywords: Freshwaters; Metal ions; Multi-parametric determination; Sequential injection lab-on-valve; Solid phase spectrophotometry