Nanoarchitectonics of on–off ratiometric signal amplified electrochemical sensor for chlorpromazine with molecularly imprinted polymer based on Ni-MOF/Fe-MOF-5 hybrid Au nanoparticles

A novel and stable on–off ratiometric electrochemical sensing platform for chlorpromazine (CPZ) detection by combing the selective recognition of molecularly imprinted polymer (MIP) technology and ratiometric quantification strategy. Gold nanoparticles (AuNPs) were first electrodeposited on a bare glassy carbon electrode surface and then modified with a mixture of Ni-MOF/Fe-MOF-5 by drop-coating, and subsequently electropolymerization polythionine (pTHi) as an internal reference to achieve a ratiometric on–off response. The reference signal of pTHi was obtained by the boiling water-bath-assisted in-situ electropolymerization method for the first time. Ni-MOF/Fe-MOF-5 hybrid AuNPs (Ni-MOF/Fe-MOF-5/AuNPs) not only benefited the output signal amplification, but also provided the enlarged surface for immobilization of pThi and MIPs, and served as catalytic active centers to oxidation CPZ. Then, the MIPs membrane was fabricated through in-situ electropolymerization by using CPZ as the template molecule, nicotinamide as a functional monomer. Ratiometric identifying and quantitative sensing model has been proposed based on the combination of MIP membrane as molecular recognition receptor and pTHi used as an internal reference probe, which improves the sensitivity and selectivity of the sensor. Under the optimal conditions, the ratiometric signals of peak current (ICPZ/IpTHi) were linear to CPZ concentration in the range of 0.001–40 μM and 40–900 μM, with the ultralow detection limit of 0.025 μM (S/N = 3). Furthermore, this sensor exhibited high anti-interference ability, reproducibility, satisfactory stability, and outstanding measurement performance in biological samples with favorable recoveries in the range of 98.11–100.81%. Together, the constructed on–off ratiometric MIP sensing platform is a promising tool for the rapid and accurate determination of antipsychotic drugs with high selectivity and stability.