Departamento de Química Analítica,Nutrición y Bromatología e Instituto Universitario de Materiales, Universidad de Alicante, E-03080, Alicante, Spain.
Laboratorio de Materiales Avanzados, Departamento de Química Inorgánica-Instituto Universitario de Materiales, Universidad de Alicante, E-03080, Alicante, Spain.
Mikrochim Acta. 2020 Jan 2;187(1):87. doi: 10.1007/s00604-019-4062-9.
Magnetic dispersive solid-phase extraction (MDSPE) is combined with electrochemical detection by using a screen-printed carbon electrode modified with gold nanoparticles to determine lead(II). A zeolite-based magnetic composite was used as sorbent during sample preparation, thus combining the unique properties of zeolites as sorbent materials with the remarkable advantages provided by magnetic materials. Three different zeolite-based magnetic composites were initially investigated and characterized. ZSM-5/FeO treated with HNO (ZSM-5/FeO) was finally selected as sorbent. Lead was extracted from urine samples using ZSM-5/FeO. After extraction, the phases were separated by using an external magnet. Subsequently, the magnetic composite carrying the analyte was directly deposited onto the working electrode of a modified screen-printed carbon electrode for final electrochemical detection. Thereby, the elution and detection of Pb(II) were carried out in a single step. A multivariate approach was employed to optimize the experimental parameters affecting extraction. Under optimized conditions and at a typical working potential of -0.23 V (vs. Ag pseudo-reference electrode), response is linear in the 0 to 25 μg L Pb(II) concentration range. The empirical limit of detection ranged from 1.0 to 2.0 μg L. The method was used to analyze Pb(II)-spiked urine samples, and apparent recoveries ranged between 99 and 107%, with coefficients of variation of <20%. Graphical abstractSchematic presentation of the analytical method to determine lead(II) in urine samples. Magnetic dispersive solid-phase extraction using a zeolite-based composite (ZSM-5/Fe2O3(tr)) is directly combined with electrochemical detection by using a screen-printed carbon electrode modified with gold nanoparticles (SPCnAuE).
磁性分散固相萃取（MDSPE）与电化学检测相结合，使用修饰有金纳米粒子的丝网印刷碳电极来测定铅（II）。在样品制备过程中，使用基于沸石的磁性复合材料作为吸附剂，从而将沸石作为吸附材料的独特性质与磁性材料的显著优势相结合。最初研究和表征了三种不同的基于沸石的磁性复合材料。最终选择用 HNO 处理的 ZSM-5/FeO（ZSM-5/FeO）作为吸附剂。使用 ZSM-5/FeO 从尿液样品中提取铅。提取后，通过外部磁铁分离各相。然后，将携带分析物的磁性复合材料直接沉积到修饰后的丝网印刷碳电极的工作电极上进行最终电化学检测。因此，洗脱和检测 Pb(II) 可以在单个步骤中完成。采用多元方法优化了影响萃取的实验参数。在优化条件下，在典型的工作电位-0.23 V（相对于 Ag 伪参比电极）下，响应在 0 至 25μg L Pb(II)浓度范围内呈线性。经验检出限范围为 1.0 至 2.0μg L。该方法用于分析 Pb(II) 加标尿液样品，表观回收率在 99%至 107%之间，变异系数<20%。
