Fluorescence-Guided Raman Spectroscopy with an Integrated Adapter for Faster and Cost-Effective Microplastic Detection

Microplastic (MP) research is a rapidly evolving field, with their presence extensively evidenced across all environmental and biological matrices. However, the lack of standardized detection techniques in MP studies presents challenges in obtaining consistent and reliable results. This study introduces an integrated analytical approach within a single instrument, enhancing efficiency and accuracy in MP analysis. A cost-effective adapter was developed to seamlessly combine fluorescence staining with Nile Red and Raman spectroscopy for MP identification and polymer type determination. The system's principle and performance were evaluated using ten different stained polymer types, demonstrating compatibility with both measurement modalities without interference. The validity was assessed by using environmental samples, including river and drinking water samples, which were analyzed using the system. An average reduction of 84 ± 8% (33 min) in analysis time was achieved, with 87 ± 6% of MPs correctly identified (19 out of 22 spectra measured) in comparison to measurements without fluorescence guided prescreening, where only 9 ± 3% of MPs were identified (10 out of 108 spectra measured). This approach improved analytical accuracy due to prescreening selectivity with fluorescence, leading to measurement times being drastically reduced. These findings suggest that the proposed system offers a significant cost-effective advancement for laboratories using Raman spectroscopy, enabling greater selectivity and higher sample throughput.