Instituto de Química, Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre, RS, Brazil.
Centro de Ciências Químicas, Farmacêuticas e de Alimentos, Universidade Federal de Pelotas, 96160-000, Pelotas, RS, Brazil.
Food Chem. 2020 Aug 15;321:126715. doi: 10.1016/j.foodchem.2020.126715. Epub 2020 Mar 30.
Sample preparation methodsforcereal digestion were evaluated for the first time for subsequent As, Cd, Hg, and Pb determination by atomic absorption spectroscopy techniques. Microwave-assisted digestion (MW-AD) under high and medium pressure and microwave-induced combustion (MIC) were evaluated. The use of MIC made it possible to digest 700 mg of samples, and agreements of 97, 96, 100 and 92% were obtained for As, Cd, Hg and Pb, respectively, when 7 mol L HNO was used as the absorbing solution. It was not necessary to dilute the digests obtained to avoid interferences in the quantification of As, Cd, Hg, and Pb. Although high pressure MW-AD was efficient for cereal digestion, interferences were observed on analyte determination. Limits of quantification obtained by MIC were 0.034 (As), 0.015 (Cd), 0.021 (Hg) and 0.105 (Pb) μg g, which are suitable to attain the maximum levels recommended by international agencies in cereal samples.
首次评估了用于后续原子吸收光谱技术测定的谷物消解的样品制备方法。评估了在高压和中压下的微波辅助消解（MW-AD）和微波诱导燃烧（MIC）。使用 MIC 可以消解 700mg 的样品，当使用 7mol/L HNO 作为吸收溶液时，分别获得了 97%、96%、100%和 92%的砷、镉、汞和铅的一致性。不需要稀释消解物以避免对砷、镉、汞和铅的定量分析产生干扰。尽管高压 MW-AD 对谷物消解有效，但在分析物测定中观察到了干扰。MIC 获得的定量下限分别为 0.034μg/g（砷）、0.015μg/g（镉）、0.021μg/g（汞）和 0.105μg/g（铅），适用于达到谷物样品中国际机构建议的最大水平。
