Microplastics are emerging contaminants that undergo progressive aging under environmental conditions such as sunlight irradiation, mechanical forces, temperature variations, and the presence of biological organisms. Since aging modifies microplastic properties, such as their own toxicity and the toxicity of trapped pollutants, advanced methods to analyze microplastics are required. Here we review methods to analyze microplastic aging with focus on the aging process, qualitative identification, quantitative characterization, and chemometrics. Qualitative identification is done by mechanical techniques, thermal techniques, e.g., thermal degradation and gas chromatography–mass spectrometry, and spectral techniques, e.g., infrared, Raman, fluorescent, and laser techniques. Quantitative characterization is done by microscopy and mass spectrometry. Microplastic aging results in a series of surface physical changes, biofilm formation, chemical oxidation, thermal alternation, and mechanical deterioration. Changes in mechanical and thermal properties allow to differentiate aged microplastics. Infrared and Raman spectroscopy are rapid and sensitive for chemical identification of microplastics in complex environmental samples. Combining two techniques is preferable for accurate detection and categorization.

微塑料是一种新兴污染物，在阳光照射、机械力、温度变化和生物有机体存在等环境条件下会逐渐老化。由于老化会改变微塑料的特性，例如其自身的毒性和截留污染物的毒性，因此需要先进的方法来分析微塑料。在这里，我们回顾了分析微塑料老化的方法，重点关注老化过程、定性识别、定量表征和化学计量学。定性鉴定通过机械技术、热技术（例如热降解和气相色谱-质谱法）和光谱技术（例如红外、拉曼、荧光和激光技术）来完成。通过显微镜和质谱法进行定量表征。微塑料老化会导致一系列表面物理变化、生物膜形成、化学氧化、热交替和机械劣化。机械和热性能的变化可以区分老化的微塑料。红外和拉曼光谱对于复杂环境样品中微塑料的化学鉴定快速且灵敏。结合两种技术更适合准确检测和分类。