Gas-liquid interface plasmonic arrays for SERS detection of microplastics

Microplastics (MPs) are widely distributed in the environment, posing significant threats to both ecosystems and human health, and have become a globally recognized pollution issue. In this study, we utilized 11-Mercaptoundecanoic acid (MUDA)-modified gold nanoparticles (AuNPs) to construct a surface-enhanced Raman spectroscopy (SERS) substrate for MPs detection. This substrate was designed at the gas–liquid interface (GLI), with AuNPs enveloping MPs at the interface, enabling in-situ detection of MPs. This approach achieved trace detection of three types of MPs-polystyrene, polyethylene terephthalate, and polycarbonate-with detection limits of 0.02620 μg mL −1 , 0.3276 μg mL −1 , and 0.2060 μg mL −1 , respectively. Additionally, polystyrene particles were dissolved as dispersed molecules in trichloromethane, eliminating the impact of the sizes of MPs, achieving a detection limit of 0.0952 μg mL −1 . To validate the practicality of this detection method, the recovery rates of seawater samples at different spiked concentrations ranged from 96.46 % to 101.52 %. The GLI SERS substrate exhibits higher sensitivity, offering increased possibilities for trace detection of MPs in aquatic environments.