Toto Benuarda, Refosco Alice, Dierkes Jutta, Kögel Tanja
Department of Clinical Medicine, Centre for Nutrition, Bergen, Norway.
Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway.
Heliyon. 2023 Jan 5;9(1):e12811. doi: 10.1016/j.heliyon.2023.e12811. eCollection 2023 Jan.
To date, microplastic is ubiquitously encountered in the environment. Studies analyzing microplastic in terrestrial ecosystems, including animal feces and feed, are few. Microplastic quantification method validation and harmonization are not yet far developed. For the analysis of small microplastic, approximately <0.5 mm, extraction from organic and inorganic materials is fundamental prior to quantitative and qualitative analysis. Method validation, including recovery studies, are necessary throughout the analytical chain. In this study, we developed an optimized, efficient protocol with a duration of 72 h for the digestion of laboratory rat feed and feces. A combination of a mild acidic (HO 15%; HNO 5%) and an alkaline treatment (10% KOH) dissolving the previous filter, followed by enzymatic digestion (Viscozyme®L) proved to be efficient for the extraction and identification of spiked polyamide (15-20 μm) and polyethylene (40-48 μm) from feed and feces samples from rats, showing high recovery rates. Extracted rat feces samples from an study in which Wistar rats were fed with feed containing microplastic were analyzed with pyrolysis-gas chromatography-Orbitrap™ mass spectrometry, quantifying recovered microplastic in rat feces in environmentally relevant concentrations. The presented three-step protocol provides a suitable, time and cost-effective method to extract microplastic from rat feed and feces.
迄今为止，微塑料在环境中无处不在。分析陆地生态系统中微塑料的研究很少，包括动物粪便和饲料。微塑料定量方法的验证和统一尚未得到充分发展。对于分析尺寸约小于0.5毫米的小微塑料，在进行定量和定性分析之前，从有机和无机材料中提取是至关重要的。在整个分析过程中，包括回收率研究在内的方法验证是必要的。在本研究中，我们开发了一种优化的、高效的方案，用于消化实验大鼠的饲料和粪便，耗时72小时。先用温和酸性溶液（15%盐酸；5%硝酸）和碱性溶液（10%氢氧化钾）溶解先前的滤膜，再进行酶解（Viscozyme®L），这种组合方法被证明对于从大鼠的饲料和粪便样本中提取和鉴定添加的聚酰胺（15 - 20微米）和聚乙烯（40 - 48微米）是有效的，回收率很高。对一项用含微塑料饲料喂养Wistar大鼠的研究中提取的大鼠粪便样本，采用热解气相色谱 - Orbitrap™质谱法进行分析，对大鼠粪便中回收的微塑料进行环境相关浓度的定量。所提出的三步方案提供了一种合适的、省时且经济高效的方法，用于从大鼠饲料和粪便中提取微塑料。
