A bifunctional electrochemical sensor for simultaneous determination of electroactive and non-electroactive analytes: A universal yet very effective platform serving therapeutic drug monitoring

A novel electrochemical sensor for therapeutic drug monitoring (TDM) of antibiotic Zavicefta was developed in this work. The main components of Zavicefta are ceftazidime (CFZ) and avibactam (AVI), wherein CFZ can be oxidized directly on electrode surface, while AVI is non-electroactive. In order to realize the simultaneous detection of the two analytes on one sensor, we elaborately constructed a dual-template molecularly imprinted polymer (MIP) modified electrode with CFZ and AVI as the templates, and further developed a dual-signal strategy. During detection, due to the inhibition effect caused by rebinding of MIP to the targets, the peak current of probe ferricyanide ([Fe(CN)6]3−) showed obvious suppression. Meanwhile, a new peak appeared, which originated from the oxidation of CFZ. The proposed sensor presented a wide linear range of 50–1000 μM for CFZ and 1–1000 μM for AVI, with the respective detection limit of 35 μM and 0.5 μM (S/N = 3). Owing to the imprinting effect of MIP, the sensor displayed excellent selectivity and anti-interference ability, which was successfully applied for TDM of CFZ and AVI in human serum and a live rabbit. The results agreed well with those from HPLC. This work is expected to offer a promising avenue for simultaneous measurement of electroactive and non-electroactive substances, and extend the potential of electrochemical sensors in medical field.