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/Fe 2 O 3 treated with HNO 3 (ZSM-5/Fe 2 O 3(tr) ) was finally selected as sorbent. Lead was extracted from urine samples using ZSM-5/Fe 2 O 3(tr) . 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 −1 Pb(II) concentration range. The empirical limit of detection ranged from 1.0 to 2.0 μg L −1 . 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 abstract Schematic 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).

中文翻译：

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使用基于沸石的复合材料进行磁分散固相萃取，使用丝网印刷电极直接电化学测定尿液中的铅 (II)

磁分散固相萃取 (MDSPE) 与电化学检测相结合，通过使用金纳米粒子修饰的丝网印刷碳电极来测定铅 (II)。在样品制备过程中使用沸石基磁性复合材料作为吸附剂，从而将沸石作为吸附剂材料的独特性能与磁性材料的显着优势相结合。最初研究并表征了三种不同的沸石基磁性复合材料。最后选择用HNO 3 (ZSM-5/Fe 2 O 3(tr) )处理的ZSM-5/Fe 2 O 3 作为吸附剂。使用 ZSM-5/Fe 2 O 3(tr) 从尿样中提取铅。萃取后，使用外部磁体进行相分离。随后，携带分析物的磁性复合材料直接沉积在改良的丝网印刷碳电极的工作电极上，用于最终的电化学检测。因此，Pb(II) 的洗脱和检测在一个步骤中进行。采用多变量方法来优化影响提取的实验参数。在优化条件和 -0.23 V（相对于 Ag 伪参比电极）的典型工作电位下，响应在 0 至 25 μg L -1 Pb(II) 浓度范围内呈线性。检测的经验极限范围为1.0至2.0 μg L -1 。该方法用于分析加标 Pb(II) 的尿液样品，表观回收率介于 99% 和 107% 之间，变异系数 <20%。图形摘要 测定尿样中铅 (II) 的分析方法的示意图。使用基于沸石的复合材料 (ZSM-5/Fe2O3(tr)) 进行磁分散固相萃取，通过使用金纳米粒子 (SPCnAuE) 修饰的丝网印刷碳电极直接结合电化学检测。