Laser-Induced Breakdown Spectroscopy for direct analysis of pristine and environmentally aged microplastics: A PCA-based approach

This study investigates the potential of Laser-Induced Breakdown Spectroscopy (LIBS) combined with Principal Component Analysis (PCA) for the differentiation and characterization of microplastics (MPs) in various stages of environmental aging. Three commonly encountered polymer types, polystyrene, polyethylene, and polyvinyl chloride, in the form of fragments were subjected to controlled aging under abiotic and biotic conditions for one and six weeks in the absence and presence of selected heavy metal ions (cadmium, chromium, and lead) to simulate environmentally relevant contamination. The LIBS-PCA approach effectively distinguishes between pristine and aged MPs and among different polymer types and aging scenarios. Biotic aging led to pronounced elemental changes which were further supported by parallel chlorophyll a measurements assessing the biofilm development. These findings highlight the applicability of LIBS-PCA as a rapid and informative tool for monitoring microplastic transformation in complex environmental settings. • LIBS differentiated pristine and aged PE, PS, and PVC MPs by PCA. • Aging under abiotic and biotic conditions altered the elemental profiles of MPs. • Biotic aging increased Mg and K levels, indicating microbial surface activity. • Abiotic aging led to Ca and Na enrichment on MP surfaces after six weeks. • One-week aging showed minimal elemental changes across all polymer types. • Chlorophyll a data confirmed biofilm formation during extended biotic aging.