Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA.
Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA; Department of Marine and Environmental Science, Northeastern University, Boston, MA, USA; Department of Civil and Environmental Engineering, Northeastern University, Boston, MA, USA.
Environ Pollut. 2023 Apr 1;322:121198. doi: 10.1016/j.envpol.2023.121198. Epub 2023 Feb 1.
Plastic pollution is a growing concern. To analyze plastics in environmental samples, plastics need to be isolated. We present an acidic/oxidative method optimized to preserve plastics while digesting synthetic cellulose acetate and a range of organics encountered in environmental samples. Cellulose acetate was chosen for optimization as it can be purchased as a reference material, can co-occur with plastics in environmental samples and, if it can be completely digested, is a potential filter material for the collection of nano- and micro-plastics from natural waters. Other forms of particulate organic matter (POM) were chosen to provide a range of chemistries that might alter digestion efficiency and due to the interest in the community of isolating plastics from samples where these organics occur. For instance, microalgal POM occurs in lake and ocean waters, riverine POM in rivers, and inclusion of tuna provides a test for the suitability of the method for isolating plastics from animal tissues. The method is a one-pot overnight (16-18 h) digestion in 5 M nitric acid with 0.3 M sodium persulfate heated to 80 °C. The method provides quantitative removal of cellulose acetate (exceeding detection limits), near quantitative removal of microalgal POM and Albacore tuna tissue (>99%), but only 86% of urban river POM, all while retaining >99% by mass of C-C bonded polymers polyethylene, polypropylene, and polystyrene and >96% by mass of polyethylene terephthalate. Fourier transform infrared spectroscopy (FT-IR) and %-C content analysis confirmed plastic polymer stability during digestion. However, some additives in appear susceptible to digestion with FT-IR results indicating the loss of N,N'-ethylenebis(stearamide) from polyethylene. This method provides a simpler and more effective method than many in the literature. We present recommendations for the application of this method, as well as limitations and areas for future improvement.
塑料污染是一个日益严重的问题。为了分析环境样品中的塑料，需要将其分离出来。我们提出了一种酸性/氧化方法，该方法经过优化，可以在消化合成醋酸纤维素和环境样品中遇到的各种有机物的同时保留塑料。选择醋酸纤维素进行优化，是因为它可以作为参考材料购买，可以与环境样品中的塑料共存，如果可以完全消化，它是从天然水中收集纳米和微塑料的潜在过滤材料。选择其他形式的颗粒有机物 (POM) 是为了提供一系列可能改变消化效率的化学物质，并且由于人们对从这些有机物存在的样品中分离塑料的兴趣。例如，微藻 POM 存在于湖泊和海洋水中，河流 POM 存在于河流中，而金枪鱼的包含提供了一种测试方法是否适合从动物组织中分离塑料的方法。该方法是一种在 5M 硝酸和 0.3M 过硫酸钠中在 80°C 下加热过夜（16-18 小时）的一锅消化法。该方法可定量去除醋酸纤维素（超过检测限）、近定量去除微藻 POM 和金枪鱼组织（>99%），但仅去除 86%的城市河流 POM，同时保留>99%的 C-C 键聚合物质量聚乙烯、聚丙烯和聚苯乙烯以及>96%的质量聚对苯二甲酸乙二醇酯。傅里叶变换红外光谱 (FT-IR) 和 %-C 含量分析证实了消化过程中塑料聚合物的稳定性。然而，一些添加剂似乎容易被消化，FT-IR 结果表明聚乙烯中 N,N'-亚乙基双（硬脂酰胺）的损失。该方法比文献中的许多方法更简单、更有效。我们提出了应用该方法的建议，以及该方法的局限性和未来改进的领域。
