title: Use of 8-hydroxyquinoline-chitosan chelating resin in an automated on-line preconcentration system for determination of zinc(II) by F AAS.
abstract: This study presents the development of an on-line preconcentration system for zinc(II) determination in aqueous samples. The analyte was trapped in a mini-column filled with a chelating resin based on a chitosan biopolymer modified with 8-hydroxyquinoline obtained by the diazotization reaction. Flow and chemical variables of the system, as well as the potential interference ions, were optimized through a multivariate procedure. The factors selected were sample pH, eluent concentration (HNO(3)), and sample and eluent flow rates. It was verified through a full factorial design that the sample pH and eluent flow rate factors were statistically significant at the 95% confidence level. A final optimization of the significant factors was carried out using a Doehlert matrix. The preconcentration system was linear between 2.5 and 75 microgL(-1), with a regression coefficient of 0.9995. The enrichment factor was 17.6. The limits of detection and quantification were 0.8 and 2.5 microgL(-1), respectively. The repeatability and the analytical frequency were, respectively, 2.7 (25.0 microgL(-1), n=8) and 18 samples per hour. Results for recovery tests using mineral water samples were between 85 and 93%. Certified reference materials were analyzed in order to check the accuracy of the proposed method.
authors.affiliation: Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil.
authors.forename: Jeferson Schneider
authors.initials: JS
authors.lastname: Carletto
authors.forename: Kalya Cravo Di Pietro
authors.initials: KC
authors.lastname: Roux
authors.forename: Heloisa França
authors.initials: HF
authors.lastname: Maltez
authors.forename: Edmar
authors.initials: E
authors.lastname: Martendal
authors.forename: Eduardo
authors.initials: E
authors.lastname: Carasek
mesh_terms: D000327:Adsorption; D002138:Calibration; D002614:Chelating Agents / Q000737:chemistry*; D048271:Chitosan / Q000031:analogs & derivatives / Q000737:chemistry; D015125:Oxyquinoline / Q000031:analogs & derivatives* / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry*; D013054:Spectrophotometry, Atomic / Q000379:methods*; D015032:Zinc / Q000032:analysis*
chemical_list: D002614:Chelating Agents; D012117:Resins, Synthetic; D015125:Oxyquinoline; C013053:8-hydroxyquinoline-5-sulfonic acid; D048271:Chitosan; D015032:Zinc