RESUMO
A method for simultaneous determination of Fe (232.036â¯nm) and Ni (232.195â¯nm) in vegetable oil samples by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS) after an acid extraction of the analytes is proposed. In the extraction step, hydrochloric, nitric and acetic acid solutions were tested. The optimization of the procedure was performed by applying Doehlert matrix, and multiple response was used for simultaneous evaluation of the performance of the extraction. The optimum conditions were: extraction time of 17â¯min, extraction temperature of 39⯰C and sonication amplitude of 42%, employing 0.5â¯molâ¯L-1 HCl as the extracting solvent. The limits of quantification were 60 and 160â¯ngâ¯g-1 for Fe and Ni, respectively. The method was applied to the analysis of vegetable oil samples and the results were compared with a method employing inductively coupled plasma optical emission spectrometry (ICP OES).
Assuntos
Fracionamento Químico/métodos , Análise de Alimentos/métodos , Ferro/análise , Níquel/análise , Óleos de Plantas/análise , Fracionamento Químico/instrumentação , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Grafite/química , Análise Multivariada , Óleos de Plantas/química , Espectrofotometria Atômica/instrumentação , Espectrofotometria Atômica/métodos , Temperatura , UltrassomRESUMO
Four species of bivalve molluscs (Anomalocardia brasiliana, Iphigenia brasiliana, Lucina pectinata and Trachycardium muricatum) were collected in the Todos os Santos Bay (TSB), Bahia, Brazil, in order to evaluate As, Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb, Se, V and Zn levels and, consequently, the risk of bivalve mollusc consumption in humans. The samples were analyzed by inductively coupled plasma optical emission spectrometry (ICP OES) and inductively coupled plasma mass spectrometry (ICP-MS) after closed-vessel microwave digestion. The accuracy was confirmed using the certified reference materials of oyster tissue (NIST 1566b) and mussel tissue (NIST 2977), and the results were statistically equivalent to the certified values. Application of principal component analysis (PCA) and hierarchical cluster analysis (HCA) showed a tendency to form two groups between samples of Lucina pectinata and Trachycardium muricatum. All species showed As and Cr concentrations higher than the maximum tolerable limit specified in Brazilian legislation.