Rapid electrochemical detection of polystyrene microplastics in aquatic environments using a gadolinium-alginate hydrogel-modified electrode

The widespread and prolonged use of plastic products, coupled with the improper disposal of plastic waste, has led to their pervasive infiltration into the environment, resulting in significant adverse impacts. Consequently, there is a growing need for a simple, portable, rapid, and reliable method to detect and analyze trace levels of microplastics in aquatic environments. In this study, we successfully developed an electrochemical sensor utilizing a glassy carbon electrode (GCE) modified with gadolinium-alginate hydrogel beads (Gd-alg5) for the detection of polystyrene (PS) microplastics with a size of approximately 100 nm. The Gd-alg5-modified electrode demonstrated efficient sensing properties, achieving a sensitivity of ~8.22 mA/μM·cm², a detection limit of 15.56 nM, and excellent repeatability and stability in detecting PS microplastics. These promising sensing parameters are likely attributed to the interactions between PS microplastics and the gadolinium cations, carboxyl groups, and hydroxyl groups present on the surface of the alginate. • Facile synthesis of Gd-alginate hydrogel beads for application as an electrochemical sensor • The sensor exhibited a detection efficiency of approximately 8.22 mA/μM·cm², with a limit of detection (LOD) of 15.56 nM. • Demonstrated excellent sensitivity, stability, and repeatability in detecting PS microplastics at 100 nm • The modified electrode was capable of detecting PS microplastics in contaminated samples.