Inkjet-printed paper-based electrochemical cell with a molecularly imprinted polymer for omeprazole detection in water.

A simple and low-cost inkjet-printed paper-based electrochemical cell incorporating a molecularly imprinted polymer (MIP) was developed for the selective detection of omeprazole (OPZ). Waterproof paper was used as the substrate for the fabrication of the electrochemical cell by inkjet printing of silver and gold conductive inks, followed by modification of the working electrode with carbon ink. The resulting cell showed good electrochemical performance, with an enhanced voltammetric response towards OPZ compared with conventional screen-printed electrodes. Printing parameters and electrode composition were optimised, and the morphology was confirmed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The functional monomer was rationally selected through computational studies based on BSSE-corrected binding energies, avoiding a trial-and-error approach. The recognition element was then obtained by electropolymerisation of p-aminobenzene sulfonic acid in the presence of OPZ, forming an imprinted polymer directly on the electrode surface. Under optimised conditions, the sensor exhibited a linear response between 0.50 and 50 µM, with limits of detection and quantification of 0.14 µM and 0.47 µM, respectively, and good selectivity against structurally related compounds. The cell was successfully applied to spiked river and well water samples, without any pre-treatment, achieving recoveries ranging from 89% to 112%. Combining simple fabrication, low cost and portability, this inkjet-printed paper-based MIP sensor shows strong potential for the on-site monitoring of pharmaceutical contaminants.