Disposable paracetamol sensor based on electroactive molecularly imprinted polymer nanoparticles for plasma monitoring

A highly sensitive disposable electrochemical sensor for paracetamol was devised using electroactive molecularly imprinted polymers nanoparticles (nanoMIPs). NanoMIPs were prepared by solid-phase synthesis. Polymer composition included itaconic acid as a specific functional monomer and ferrocene as redox label, which confers electroactivity to the nanoparticles. NanoMIPs were characterised by Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) and scanning electron microscopy (SEM). Sensors were fabricated by covalent attachment of nanoMIPs on screen-printed carbon electrodes and then employed for electrochemical determination of paracetamol using differential pulse voltammetry (DPV). The sensor was successfully evaluated in spiked human plasma with recoveries at 94–108 % and presenting a sensitivity of 6.18 ± 0.22 μA mM−1. The limit of detection and limit of quantification for the sensor were found to be 50 μM and 167 μM, respectively, in a linear concentration range between 0.1 and 1 mM. High selectivity was demonstrated, with no interference found in the presence of caffeine, procainamide or ethyl 4-aminobenzoate. The sensors exhibited high reproducibility (RSD, 4.8 %), fast response time (∼8 s) and acceptable shelf life (90 days), confirming its suitability for point of care diagnostic applications.