Amostragem direta de biossorvente sólido magnético em Espectrometria de Absorção Atômica com Chama para a determinação de Chumbo em sucos

Abstract

The consumption of industrialized juices has grown in recent years, due their benefits for those seeking a healthier diet. However, juices can be contaminated with several toxic compounds that pose risks to the health of consumers, as for example toxic metals. The main sources of metals are in the cultivation of fruits, as they can be naturally present in the soil or be inserted through fertilizers or by the irrigation water. In this way, regulatory agencies, such as ANVISA, play a fundamental role in the establishing the limits for different toxic metals in foods, including industrialized juices and nectars. In addition, the development of new analytical methodologies is important to the contaminant monitoring, main in complex samples. In this context, the present work evaluate the use of a magnetic biosorbent in dispersive solid phase extraction of lead from industrialized soy-based juices, followed by quantification through the direct magnetic sorbent sampling flame atomic absorption spectrometry (DMSS-FAAS). This technique was recently proposed by our research group, and it promotes a significant gain in sensitivity when compared to conventional metodology. The magnetic biosorbent was synthesized with orange peel powder by incorporation of magnetite nanoparticles. Characterizations were performed by thermogravimetric analyses, infrared spectroscopy, surface charge analysis and transmission electron microscopy. A multivariate optimization of the extraction parameters (extraction time, sample pH and sample volume) was performed, followed by the construction of analytical curves in water and juices. The analytical curves ranged from 5 to 140 μg L -1 in water, 10 to 300 μg L -1 in soy-based juice and 10 to 150 μg L -1 for whole grape juice, reconstituted grape juice and orange nectar, with correlation coefficients were greater than 0.99 for all cases. The detection limits were between 0.97 and 4.58 μg L -1 and the quantification limits were 2.94 and 13.89 μg L -1 . The intraday and interday precisions (expressed as RSD%) were between 2.2 and 25.0%. Intraday accuracies (expressed as RE%) were between 0.3 and 24.5%.