Zou Ya-Dan, Xu Qing-Qing, Zhang Ge, Li Fu-Yun, Li Feng-Min
Key Laboratory of Marine Environment and Ecology, Ministry of Education, Institute of Coastal Environmental Pollution Control, Ocean University of China, Qingdao 266100, China.
Huan Jing Ke Xue. 2019 Jan 8;40(1):496-503. doi: 10.13227/j.hjkx.201804072.
Microplastic pollution has become a global environmental problem and is a cause of great concern. To evaluate the biological effects of microplastics, microplastics in organisms need to be accurately quantified. The quantification of microplastics in organisms using the fluorescence intensity is common; the digestion of biological samples is an important pretreatment method. However, the microplastics may be destroyed by digestion, which affects the fluorescence intensity of the microplastics and results in large deviations between measured and true values. In this study, six commonly used digestive agents were studied:KOH, NaOH, HO, HNO, HNO:HCl, and HNO:HClO. The effect of different digestion methods on the fluorescence intensity and surface morphology of microplastics was studied and the most suitable protocol was selected. The results show that, among the six different digestion methods, KOH digestion (100 g·L, 60℃) has the least influence on the fluorescence intensity of the microplastics and does not affect their surface morphology. The other five digestion methods lead to different degrees of reduction of the fluorescence intensity of microplastics and damage the microplastics' surface (aggregation, bubbles, scratches, and depressions). In addition, the KOH digestion method was used to extract microplastics from biological samples. The recovery rate was ≥ 96.3%±0.5%, indicating that the KOH digestion method is suitable for fluorescent microplastics in biological samples.
微塑料污染已成为一个全球性的环境问题，备受关注。为了评估微塑料的生物学效应，需要准确量化生物体中的微塑料。利用荧光强度对生物体中的微塑料进行量化很常见；生物样品的消解是一种重要的预处理方法。然而，微塑料可能会因消解而被破坏，这会影响微塑料的荧光强度，导致测量值与真实值之间存在较大偏差。在本研究中，对六种常用的消解剂进行了研究：氢氧化钾（KOH）、氢氧化钠（NaOH）、过氧化氢（H₂O₂）、硝酸（HNO₃）、硝酸：盐酸（HNO₃：HCl）和硝酸：高氯酸（HNO₃：HClO₄）。研究了不同消解方法对微塑料荧光强度和表面形态的影响，并选择了最合适的方案。结果表明，在六种不同的消解方法中，氢氧化钾消解（100 g·L⁻¹，60℃）对微塑料荧光强度的影响最小，且不影响其表面形态。其他五种消解方法导致微塑料荧光强度不同程度降低，并损害微塑料表面（聚集、气泡、划痕和凹陷）。此外，采用氢氧化钾消解方法从生物样品中提取微塑料。回收率≥96.3%±0.5%，表明氢氧化钾消解方法适用于生物样品中的荧光微塑料。
