Enrichment coupled electrochemical sensing for one-pot microplastic quantification

Abstract

The migration from food packaging and enduring presence for bioaccumulation have enabled microplastics to be the potential pollutants for human health and the environment safety. The high dispersity and migration of microplastics increased the detection challenges. Herein, a one-pot enrichment and electrochemical sensing platform was constructed for polystyrene microplastics (PS MPs) quantification. Magnetic Fe3O4 nanoparticles (MNPs) were firstly utilized for the capture of PS MPs through swelling method, and electroactive Ag NPs were applied as detection tags for the adsorption on the surface of PS MPs. The composites of MNPs, PS MPs and Ag NPs (MPS@Ag structures) enabled the rapid magnetic enrichment of PS MPs within 30 s, and Ag NPs generated distinct electrochemical oxidation peak at +0.19 V, serving as an interference-free electrochemical signal. The electrochemical oxidation signal exhibited a linear response to PS MPs concentrations in the range of 0.01–0.5 mg·mL−1. The limit of detection was 1.4 ppm. This magneto enrichment coupled with electrochemical sensing principle constructed an integrated platform of “capture-enrichment-identification”, marking an innovative shift from passive monitoring to active intervention in the field of microplastics prevention and control.