title: Determination of arsenic species in rice samples using CPE and ETAAS.
abstract: A highly sensitive and selective procedure for the determination of arsenate and total arsenic in food by electrothermal atomic absorption spectrometry after cloud point extraction (ETAAS/CPE) was developed. The procedure is based on the formation of a complex of As(V) ions with molybdate in the presence of 50.0 mmol L(-1) sulfuric acid. The complex was extracted into the surfactant-rich phase of 0.06% (w/v) Triton X-114. The variables affecting the complex formation, extraction and phase separation were optimized using factorial designs. Under the optimal conditions, the calibration graph was linear in the range of 0.05-10.0 μg L(-1). The detection and quantification limits were 10 and 33 ng L(-1), respectively and the corresponding value for the relative standard deviation for 10 replicates was below 5%. Recovery values of between 90.8% and 113.1% were obtained for spiked samples. The accuracy of the method was evaluated by comparison with the results obtained for the analysis of a rice flour sample (certified material IRMM-804) and no significant difference at the 95% confidence level was observed. The method was successfully applied to the determination of As(V) and total arsenic in rice samples.
authors.affiliation: Departamento de Química, Universidade Federal de Goiás, Campus Catalão, Av. Doutor Lamartine Pinto de Avelar, 1120 Setor Universitário, CEP 75704-020 Catalão, GO, Brazil.
authors.forename: Bruno Elias Dos Santos
authors.initials: BE
authors.lastname: Costa
authors.affiliation: Instituto de Química, Universidade Federal de Uberlândia, Av. João Naves de Ávila 2121, CEP 38400-902 Uberlândia, MG, Brazil.
authors.forename: Nívia Maria Melo
authors.initials: NM
authors.lastname: Coelho
authors.affiliation: Departamento de Química, Universidade Federal de Goiás, Campus Catalão, Av. Doutor Lamartine Pinto de Avelar, 1120 Setor Universitário, CEP 75704-020 Catalão, GO, Brazil. Electronic address: lucianacatalao@hotmail.com.
authors.forename: Luciana Melo
authors.initials: LM
authors.lastname: Coelho
mesh_terms: D001151:Arsenic / Q000032:analysis*; D005506:Food Contamination / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D012275:Oryza / Q000737:chemistry*; D013054:Spectrophotometry, Atomic / Q000379:methods*; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D013501:Surface-Active Agents; D001151:Arsenic
keywords: Arsenic; Cloud point extraction; ETAAS; Rice