Sobhani Zahra, Al Amin Md, Naidu Ravi, Megharaj Mallavarapu, Fang Cheng
Global Centre for Environmental Remediation (GCER), University of Newcastle, Callaghan, NSW, 2308, Australia.
Global Centre for Environmental Remediation (GCER), University of Newcastle, Callaghan, NSW, 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), University of Newcastle, Callaghan, NSW, 2308, Australia.
Anal Chim Acta. 2019 Oct 24;1077:191-199. doi: 10.1016/j.aca.2019.05.021. Epub 2019 May 16.
Recently, microplastics (MP) have emerged as global contaminants of serious concern to human and ecological health. However, identification and visualisation of MP are still a challenge, whether from wastewater, oceans, sediment or soil. Particularly when MP are mapped to visualise their distribution, the background signal from sediment and soil might be high and shield the MP signal from the analysis. Raman has recently received increasing attention, as the complementary spectrum of infrared (IR), because it can overcome the drawbacks of IR analysis including water interference, low lateral resolution and a complex spectrum. Here we show that Raman can identify and visualise MP from a soil/sand background, with almost no sample preparation, no dye, no destruction of the sample and no interference from water/organic matter/fluorescence background signals as well. By mapping image via their characteristic and fingerprint peaks, MP including polystyrene (PS), polyethylene terephthalate (PET), polyethylene (PE), polyvinyl chloride (PVC) and polypropylene (PP) can be individually identified and visualised. The lateral resolution along the focal plane is 1 μm/pixel to catch small MP down to 1 μm.
最近，微塑料已成为全球范围内严重威胁人类和生态健康的污染物。然而，无论是来自废水、海洋、沉积物还是土壤，微塑料的识别和可视化仍然是一项挑战。特别是当绘制微塑料分布图以显示其分布时，沉积物和土壤的背景信号可能很强，会掩盖微塑料信号，影响分析。拉曼光谱作为红外光谱的补充光谱，最近受到越来越多的关注，因为它可以克服红外分析的缺点，包括水干扰、横向分辨率低和光谱复杂等问题。在这里，我们展示了拉曼光谱可以在几乎不进行样品制备、不使用染料、不破坏样品且不受水/有机物/荧光背景信号干扰的情况下，从土壤/沙子背景中识别和可视化微塑料。通过绘制其特征峰和指纹峰的图像，可以单独识别和可视化包括聚苯乙烯（PS）、聚对苯二甲酸乙二酯（PET）、聚乙烯（PE）、聚氯乙烯（PVC）和聚丙烯（PP）在内的微塑料。沿焦平面的横向分辨率为1μm/像素，能够捕捉低至1μm的微小微塑料。
