μ-FTIR Reflectance Spectroscopy Coupled with Multivariate Analysis: A Rapid and Robust Method for Identifying the Extent of Photodegradation on Microplastics

作者：Eleonora Conterosito, Maddalena Roncoli, C Ivaldi, Marysol Ferretti, Beatrice De Felice, Marco Parolini, Stefano Gazzotti, Marco Aldo Ortenzi, Valentina Gianotti · 发表于：Analytical Chemistry · 年份：2025 · DOI：10.1021/acs.analchem.4c04281 · 被引用次数：25 · 研究领域：Microplastics and Plastic Pollution、Recycling and Waste Management Techniques、Biosensors and Analytical Detection

Understanding the origins of microplastics (MPs) and evaluating the consequences of plastic pollution require precise chemical information. Moreover, MPs undergo chemical changes due to photoaging, which are worth investigating since they can influence the effects of MPs on living beings and the environment. Micro-Fourier-transform infrared (μ-FTIR) spectroscopy is a key technique for screening MPs, combining optical imaging with chemical information from IR spectra. While reflectance μ-FTIR spectroscopy's sensitivity to particle thickness and photodegradation complicates automated spectral matching, it can provide valuable information if coupled with multivariate analysis of the data. This study developed a robust method for identifying MPs, even when they are modified by photodegradation. Various acquisition methods (ATR-IR and μ-transflectance-IR), data pretreatments, and data set analysis procedures were examined, and critical aspects were addressed. The proposed method, using μ-TR-IR and principal component analysis (PCA), proved effective for classifying MPs and analyzing their degradation, offering increased sensitivity and a faster workflow compared with manual spectral comparison. μ-TR-IR showed earlier changes in relevant bands, indicating higher sensitivity to degradation than ATR-IR spectroscopy. Despite the notorious issue of spectral artifacts, our results suggest that valuable information can be collected without using sophisticated preprocessing techniques. On...