Desenvolvimento de método analítico empregando RP-DLLME no preparo de amostras de banha suína para posterior determinação de Cd e Pb por F AAS

Abstract

The swine fat popularly called lard comes from an animal source, usually solid at room temperature. This product, in addition to being used in the manufacture of animal nutrients, is present in the cooking and feeding of millions of people. The presence of heavy metals may be contained in this material because the animal absorbs it in its body, being found in higher concentrations in organs and viscera. The method proposed in this work comprises the determination of Cd and Pb, providing a method with simple characteristics, fast execution and low consumption and waste rates, resulting from the use of reagents, making it a less toxic method of execution. Some literatures were followed as parameters for the possibility of using reversed-phase liquid-liquid dispersive microextraction (RP-DLLME) for solid fats such as lard. This work proposes an optimized method of sample preparation using RP – DLLME for further determination in Cd and Pb by flame absorption spectrometry (F AAS). As a result of the determination method, the procedure was adjusted using 5 g of sample, heating in a water bath at 70 °C for 20 min, addition of 5 ml of xylene solvent to avoid solidification during the process, subsequent injection of the extracting solution, containing 70% dispersing agent (n-propanol) and 30% extracting agent (HNO3 1.0 mol L-1, v.v-1), followed by mechanical vortexing for 1 min and centrifugation for 10 min at 6000 RPM and 25°C. Flame absorption spectrometry (F AAS) is conditioned to detection of numerous metals at trace level concentrations also due to its simplicity, speed and low cost.