Surface-enhanced raman scattering technique for nanoplastics detection

The size-dependent effect of nanoplastics (NPLs) restricts the quantification of NPLs by surface-enhanced Raman scattering (SERS) technique. In this study, we successfully established an innovative preparation method to eliminate this effect. This developed SERS method allowed us to quantify 100-, 300-, 600-, and 800-nm polystyrene nanospheres (PSNSs) in diverse aqueous conditions at a low concentration. The SERS substrate was easily fabricated and used as NPLs signal enhancement with sputtering gold particles onto a glass cover slide. By preconcentrating and dissolving PSNSs in toluene, SERS technique can be successfully quantify NPLs at extremely low concentrations with a limit of detection (LOD) down to 0.12 µg/mL. Moreover, the SERS method was also performed in several media such as salts, sugars, amino acids, and detergents in order to investigate the interference effect. Moreover, the SERS method was effectively validated for quantitative analysis of a mixture of 100-, 300-, 600-, and 800-nm PSNSs in a ratio of 1:1:1:1 in real-world media (i.e., tap water, mineral water, and river water). Using our proposed method, the SERS technique successfully approaches the evaluation of PSNSs in the range of 10 to 40 µg/mL with a LOD of down to 0.32–0.52 µg/mL.