Determination of Polystyrene Nanoparticles in Aqueous Solutions by Dual-Beam Thermal Lens Spectrometry

Polymer micro- and nanoparticles, commonly known as microplastics, are significant environmental pollutants. Even low concentrations of microplastics can affect ecosystems and human health, underscoring the urgent need in detecting these particles in low concentrations while simultaneously assessing the physicochemical parameters of the studied systems. Thermal lens spectrometry (TLS) has effectively detected polystyrene particles measuring 65 and 80 nm within a concentration range of 0.0005–0.15 mg/L in their aqueous dispersions. The comprehensive TLS data also facilitated the evaluation of the thermal diffusivity of these solutions. An increase in the concentration of polystyrene nanoparticles in water results in a nonlinear change in thermal diffusivity.