On‐Line Solid Phase Extraction and Determination of Copper in Food Samples Using Polyurethane Foam Loaded with Me‐BTANC

Abstract

An on‐line solid‐phase extraction system for preconcentration and determination of copper in food samples is proposed. Polyurethane foam loaded with Me‐BTANC packed in a minicolumn was used as sorbent. Copper (II) ions were sorbed in the minicolumn, and the elution of the retained analytes on the column was performed with hydrochloric acid solution. This eluate reacted with Br‐PADAP, and the absorbance of the complex was read at 550 nm in a spectrophotometer. Analytical parameters were evaluated, and the results demonstrated that copper can be determined at sample pH inthe range of 7.0–8.5, preconcentration time of 90 s, and a sample flow rate of 6.5 mL min−1. The detection limit (3 s) was 1.2 µg L−1, and the relative standard deviations at 10 and 150 µg L−1 levels of analyte ions reached values of 6.3 and 2.9%, respectively. Recoveries of spike addition to dried shrimp samples were quantitative (91–108%). Supported by the Fundação de Amparo à Pesquisa do Estado da Bahia (FAPESB), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Financiadora de Estudos e Projetos (FINEP).