Molecular Imprinted Polymers (MIP)-Based Electrochemical Sensing of Micro/Nano Polystyrene

This article is based on the electrochemical sensing of micro- and/or nano-sized polystyrene (m/n-PS). A molecularly imprinted polymer (MIP)-based electrochemical sensing of nano polystyrene (nPS) of 100 nm and 500 nm sizes is demonstrated in this article. Poly-o-phenylenediamine (PoPD) is adopted as the MIP material and fabricated electrochemically (i.e., electro-polymerization) on the surface of the screen-printed carbon electrode (SPCE), using o-phenylenediamine (oPD) as the monomer. To fabricate MIP selective to m/n-PS, PS of 100 and 500 nm were utilized as template material. Fabrication of the PoPD@MIP@SPCE system targeting m/n-PS was characterized using electrochemical techniques to understand the electrochemical properties and electrochemical sensing. Finally, such optimized MIPs@PoPD/SPCE sensing chips were utilized to demonstrate electrochemical sensing of a range of concentrations of nPS solutions (100 and 500 nm-sized PS), ranging from 4.2 x 10^-9 to 2.1 x 10^-4 g/L in water. The lowest concentration detected by the developed sensing chip is as low as 4.2 x 10^-9 g/L, and the related operation time is 11 min. These sensors were also utilized to detect nPS in water samples that were collected from the Florida Polytechnic University lake. Such a proposed sensing method can be utilized for nPS sensing in point-of-care (POC) sensing, which is of great importance for environmental surveillance applications.