贻贝中微塑料检测的消解方法比较

Comparison of digestion methods for the detection of microplastics in Mytilus eduli

中文关键词:  微塑料  消解  贻贝  红外光谱  粒径分布  扫描电镜

英文关键词:microplastics  digestion  Mytilus eduli  infrared spectrum  particle size distribution  scanning electron microscope

中文摘要:

      目的 比较贻贝中微塑料(microplastics, MPs)检测常用的酸消解、碱消解、氧化消解和酶消解等方法, 推荐适用于贝类中微塑料检测的通用型消解方式。方法 以常用的指示性双壳贝类贻贝作为研究对象, 确定食品样品检测通用的消解条件。在这些条件下对聚苯乙烯(polystyrene, PS)、聚丙烯(polypropylene, PP)、聚碳酸酯(polycarbonate, PC)、聚乙烯(polyethylene, PE)、聚对苯二甲酸乙二醇酯(polyethylene terephthalate, PET)、聚酰胺6 (polyamide, PA6)和聚酰胺66 (polyamide, PA66) 7种微塑料进行消解, 考察不同条件下微塑料粒子消解前后重量、红外光谱、粒径分布和形貌特征的变化。结果 采用不同的消解方式对不同的微塑料影响不同, 其中重量受影响较大的是PA6和PA66, 在硝酸-高氯酸混合溶液和高氯酸-双氧水混合溶液中完全溶解损失, PC和PET在氢氧化钾溶液中损失严重。通过结构表征, PE、PA6和PC的粒径增加, PC的形貌结构发生彻底改变。结论 对微塑料含量甚微的双壳贝类样品的检测, 推荐采用胃蛋白酶溶液和胰蛋白酶溶液进行消解; 如需缩短消解时间, 推荐采用双氧水在高温下消解。

英文摘要:

      Objective To compare the acid digestion, alkali digestion, oxidation digestion and enzyme digestion methods commonly used in the detection of microplastics (MPs) in Mytilus eduli, and recommend a universal digestion method suitable for the detection of microplastics in shellfish. Methods The commonly used indicative bivalve Mytilus eduli were selected as the research objects to optimize the general digestion conditions of food, under which polystyrene (PS), polypropylene (PP), polycarbonate (PC), polyethylene (PE), polyethylene terephthalate (PET), polyamide 6 (PA6) and polyamide 66 (PA66) were digested. The weight, infrared spectrum, particle size distribution and morphological characteristics of the MPs before and after digestion were characterized. Results Different digestion methods had different effects on different MPs, among which PA6 and PA66 were the most affected. PA6 and PA66 were completely dissolved in nitric acid-perchloric acid mixed solution and perchloric acid-hydrogen peroxide mixed solution, while PC and PET were seriously lost in potassium hydroxide solution. Through structural characterization, the particle sizes of PE, PA6 and PC increased, and the morphology and structure of PC changed completely. Conclusion For the detection of bivalve shellfish samples with little microplastic content, pepsin solution and trypsin solution are recommended for digestion; if the digestion time needs to be shortened, it is recommended to use hydrogen peroxide for digestion at high temperature.