Determination of Trace Elements in Meat and Fish Samples by MIP OES Using Solid-Phase Extraction

Abstract

A new procedure for the determination of As, Cd, Cr, Cu, Hg, Pb, and Zn in fish and meat (bovine and ovine) samples by microwave-induced plasma optical emission spectrometry (MIP OES) was developed. The procedure is based on separation and preconcentration of analytes by solid-phase extraction (SPE), composed from the functionalization of silica with p-aminobenzoic acid (PABA-MCM-41). Factors that directly affect the SPE procedure as pH, buffer concentration, sample flow, and elution flow were evaluated through a factorial design (24). The optimized conditions employed at the proposed procedure were as follows: pH 9.5, 0.01 mol L−1 borate buffer concentration, sampling, and 6.0 mL min−1 of elution flow. Linear models were treated regarding the weighted regression, an optional strategy of the equipment, the weighted fit. The proposed procedure provides limits of quantification (LOQ) of 9.6, 2.8, 0.1, 0.2, 1.5, 13.3, and 3.9 μg g−1 for As, Cd, Cr, Cu, Hg, Pb, and Zn, respectively. Accuracy was assessed from the analysis of the certified reference materials (CRM) of dogfish liver (DOLT-5, NRC) and bovine liver (1577c, NIST), and a reference material of bovine liver (RM-Agro E3001a, EMBRAPA). The procedure was applied in local market meats (bovine and ovine) and fish (tilapia) samples, and it showed adequate for the determination of As, Cd, Cr, Cu, Hg, Pb, and Zn by MIP OES.