Savino Ilaria, Campanale Claudia, Trotti Pasquale, Massarelli Carmine, Corriero Giuseppe, Uricchio Vito Felice
Italian National Council of Research, Water Research Institute, 70132 Bari, Italy.
Department of Biology, University of Bari Aldo Moro, 70121 Bari, Italy.
Polymers (Basel). 2022 May 11;14(10):1958. doi: 10.3390/polym14101958.
Although several sample preparation methods for analyzing microplastics (MPs) in environmental matrices have been implemented in recent years, important uncertainties and criticalities in the approaches adopted still persist. Preliminary purification of samples, based on oxidative digestion, is an important phase to isolate microplastics from the environmental matrix; it should guarantee both efficacy and minimal damage to the particles. In this context, our study aims to evaluate Fenton's reaction digestion pre-treatment used to isolate and extract microplastics from environmental matrices. We evaluated the particle recovery efficiency and the impact of the oxidation method on the integrity of the MPs subjected to digestion considering different particles' polymeric composition, size, and morphology. For this purpose, two laboratory experiments were set up: the first one to evaluate the efficacy of various digestion protocols in the MPs extraction from a complex matrix, and the second one to assess the possible harm of different treatments, differing in temperatures and volume reagents used, on virgin and aged MPs. Morphological, physicochemical, and dimensional changes were verified by Scanning Electron Microscope (SEM) and Fourier Transformed Infrared (FTIR) spectroscopy. The findings of the first experiment showed the greatest difference in recovery rates especially for polyvinyl chloride and polyethylene terephthalate particles, indicating the role of temperature and the kind of polymer as the major factors influencing MPs extraction. In the second experiment, the SEM analysis revealed morphological and particle size alterations of various entities, in particular for the particles treated at 75 °C and with major evident alterations of aged MPs to virgin ones. In conclusion, this study highlights how several factors, including temperature and polymer, influence the integrity of the particles altering the quality of the final data.
尽管近年来已经实施了几种用于分析环境基质中微塑料（MPs）的样品制备方法，但所采用的方法仍存在重要的不确定性和关键性问题。基于氧化消解的样品初步纯化是从环境基质中分离微塑料的重要阶段；它应保证效率和对颗粒的最小损害。在此背景下，我们的研究旨在评估用于从环境基质中分离和提取微塑料的芬顿反应消解预处理。我们考虑了不同颗粒的聚合物组成、尺寸和形态，评估了颗粒回收效率以及氧化方法对经过消解的微塑料完整性的影响。为此，设置了两个实验室实验：第一个实验评估各种消解方案从复杂基质中提取微塑料的效果，第二个实验评估在温度和所用试剂体积不同的情况下，不同处理对原始微塑料和老化微塑料可能造成的损害。通过扫描电子显微镜（SEM）和傅里叶变换红外（FTIR）光谱对形态、物理化学和尺寸变化进行了验证。第一个实验的结果表明，回收率差异最大，尤其是对于聚氯乙烯和聚对苯二甲酸乙二酯颗粒，这表明温度和聚合物种类是影响微塑料提取的主要因素。在第二个实验中，SEM分析揭示了各种实体的形态和粒径变化，特别是对于在75°C下处理的颗粒，老化微塑料相对于原始微塑料有更明显的变化。总之，本研究强调了包括温度和聚合物在内的几个因素如何影响颗粒的完整性，从而改变最终数据的质量。
