A novel voltammetric sensor based on graphene quantum dots-thionine/nano-porous glassy carbon electrode for detection of cisplatin as an anti-cancer drug

In this study, a novel electrochemical sensor for the detection of cisplatin, an anti-cancer drug, was introduced. Graphene quantum dots (GQDs) modified with thionine were synthesised for the first time and immobilised as a suitable nanostructure modifier on the nano-porous glassy carbon electrode (npGCE) for selective and sensitive determination of cisplatin. The morphology of the GQDs-thio/npGCE surface was specified by electrochemical impedance spectroscopy (EIS) and the field-emission scanning electron microscopy (FE-SEM). The linear range of anodic stripping response to drug concentration was 0.2–110 μM with the detection limit (S/N = 3) of 90 nM, compared with previous studies, the lowest LOD for cisplatin has been obtained. The proposed electrode was sensitive, selective, and its applicability was tested by analysing cisplatin in biological fluids, including blood serum and urine samples. The recovery experiments were performed with both real samples spiked with the drug at different concentration levels and resulted in almost quantitative recoveries (between 98 and 104%). Fluorescence spectroscopic and electrochemical methods examined the interaction of cisplatin-thionine.