†Brunel University London, Experimental Techniques Centre, Institute of Materials and Manufacturing, Bragg Building, Kingston Lane, Uxbridge, Middlesex, United Kingdom, UB8 3PH.
‡Fera Science Ltd., Sand Hutton, York, United Kingdom, YO41 1LZ.
Anal Chem. 2015 Jun 16;87(12):6032-40. doi: 10.1021/acs.analchem.5b00495. Epub 2015 May 29.
Microplastics (<5 mm) have been documented in environmental samples on a global scale. While these pollutants may enter aquatic environments via wastewater treatment facilities, the abundance of microplastics in these matrices has not been investigated. Although efficient methods for the analysis of microplastics in sediment samples and marine organisms have been published, no methods have been developed for detecting these pollutants within organic-rich wastewater samples. In addition, there is no standardized method for analyzing microplastics isolated from environmental samples. In many cases, part of the identification protocol relies on visual selection before analysis, which is open to bias. In order to address this, a new method for the analysis of microplastics in wastewater was developed. A pretreatment step using 30% hydrogen peroxide (H2O2) was employed to remove biogenic material, and focal plane array (FPA)-based reflectance micro-Fourier-transform (FT-IR) imaging was shown to successfully image and identify different microplastic types (polyethylene, polypropylene, nylon-6, polyvinyl chloride, polystyrene). Microplastic-spiked wastewater samples were used to validate the methodology, resulting in a robust protocol which was nonselective and reproducible (the overall success identification rate was 98.33%). The use of FPA-based micro-FT-IR spectroscopy also provides a considerable reduction in analysis time compared with previous methods, since samples that could take several days to be mapped using a single-element detector can now be imaged in less than 9 h (circular filter with a diameter of 47 mm). This method for identifying and quantifying microplastics in wastewater is likely to provide an essential tool for further research into the pathways by which microplastics enter the environment.
微塑料（<5 毫米）已在全球范围内的环境样本中被记录下来。虽然这些污染物可能通过废水处理设施进入水生环境，但这些基质中微塑料的丰度尚未被研究过。尽管已经发表了用于分析沉积物样品和海洋生物中微塑料的有效方法，但尚未开发出用于检测这些污染物在富含有机物的废水中的方法。此外，没有标准化的方法来分析从环境样品中分离出来的微塑料。在许多情况下，部分鉴定方案依赖于分析前的目视选择，这容易产生偏差。为了解决这个问题，开发了一种用于分析废水中微塑料的新方法。使用 30%过氧化氢（H2O2）的预处理步骤用于去除生物源物质，基于焦平面阵列（FPA）的反射微傅里叶变换（FT-IR）成像被证明可以成功地对不同类型的微塑料（聚乙烯、聚丙烯、尼龙-6、聚氯乙烯、聚苯乙烯）进行成像和识别。使用微塑料掺杂的废水样品对该方法进行了验证，结果表明该方法具有稳健性、非选择性和重现性（总体成功识别率为 98.33%）。与以前的方法相比，基于 FPA 的微 FT-IR 光谱学的使用还提供了显著缩短分析时间的优势，因为使用单元素探测器可能需要数天才能绘制的样品现在可以在不到 9 小时内成像（直径为 47 毫米的圆形过滤器）。这种用于识别和量化废水中微塑料的方法可能为进一步研究微塑料进入环境的途径提供必要的工具。
