Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, P. R. China.
State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen 361102, P. R. China.
Anal Chem. 2022 Sep 20;94(37):12657-12663. doi: 10.1021/acs.analchem.2c01703. Epub 2022 Sep 7.
Most food packages are made of plastics, nanoplastics released from which can be directly ingested and induce serious damage to organisms. Therefore, it is urgent to develop an effective and convenient method for nanoplastic determinations in food packages. In this work, we present a sandwich-based electrochemical strategy for nanoplastic determination. Positively charged Au nanoparticles were coated onto a Au electrode to selectively capture negatively charged nanoplastics in an aqueous environment. Subsequently, the nanoplastics were recognized by the signal molecule ferrocene via the hydrophobic interaction and determined by differential pulse voltammetry. Our sandwich-type detection depends on both electronegativity and hydrophobicity of nanoplastics, which make the method applicable for the assays of packages made of widely commercialized polystyrene (PS), polypropylene (PP), polyethylene (PE), and polyamide (PA). The method displays different sensitivities to above four nanoplastics but the same dynamic range from 1 to 100 μg·L. Based on it, the nanoplastics released from several typical food packages were assayed. Teabags were revealed with significant nanoplastic release, while instant noodle boxes, paper cups, and take-out boxes release slightly. The good recoveries in nanoplastic-spiked samples confirm the accuracy and applicability of this method. This work provides a sensitive, low-cost, and simple method without complicated instruments and pretreatment, which is of great significance for the determination of nanoplastics released from food packages.
大多数食品包装都是由塑料制成的，其中释放的纳米塑料可以被直接摄入，并对生物体造成严重损害。因此，迫切需要开发一种有效和方便的方法来检测食品包装中的纳米塑料。在这项工作中，我们提出了一种基于三明治的电化学策略来检测纳米塑料。带正电荷的金纳米粒子被涂覆在金电极上，以在水相环境中选择性地捕获带负电荷的纳米塑料。随后，纳米塑料通过疏水相互作用被信号分子二茂铁识别，并通过差分脉冲伏安法进行检测。我们的三明治型检测依赖于纳米塑料的电负性和疏水性，这使得该方法适用于广泛商业化的聚苯乙烯（PS）、聚丙烯（PP）、聚乙烯（PE）和聚酰胺（PA）制成的包装的检测。该方法对上述四种纳米塑料显示出不同的灵敏度，但动态范围相同，为 1 至 100μg·L。基于该方法，对几种典型食品包装释放的纳米塑料进行了检测。茶包被发现有明显的纳米塑料释放，而方便面盒、纸杯和外卖盒则有轻微释放。在纳米塑料加标样品中的良好回收率证实了该方法的准确性和适用性。这项工作提供了一种灵敏、低成本、简单的方法，无需复杂的仪器和预处理，对检测食品包装中释放的纳米塑料具有重要意义。
