Surface plasmon resonance (EC-SPR) sensor based on molecularly imprinted strategy for the determination of stimulant modafinil in saliva samples

A highly sensitive and selective molecularly imprinted polymer-based electrochemical-surface plasmon resonance (MIP-based EC-SPR) sensor was developed for the determination of modafinil in saliva samples. The optimal MIPpy film was synthesized using a modafinil concentration of 1 mM and a constant potential electropolymerization method. The fabricated sensor exhibited a wide linear range (0.1 μM to 10 μM), low detection limits (LOD: 50 nM, LOQ: 170 nM), and high selectivity towards modafinil, with selectivity coefficients of 8.5, 6.2, and 12.7 for adrafinil, armodafinil, and caffeine, respectively. The sensor also demonstrated excellent reproducibility (RSD: 4.2 %) and long-term stability (92 % response after one month). Furthermore, the applicability of the sensor in real samples was validated using spiked saliva samples, with recovery values ranging from 94.7 % to 103.5 %. These results highlight the potential of the MIP-based EC-SPR sensor as a powerful tool for the rapid, sensitive, and selective detection of modafinil in complex biological matrices.