Analytical methodology for the electro-catalytic determination of estradiol and progesterone based on graphene quantum dots and poly(sulfosalicylic acid) co-modified electrode

The goal of this study was to develop an electroanalytical method for the simultaneous determination of steroid hormones for the first time. The key factor in the electrochemical methods is the choice of suitable electrode materials. For this purpose, graphene quantum dots (GQDs) doped poly(sulfosalicylic acid) (PSSA) was immobilized on a glassy carbon electrode (GCE). Apart from exhibition strong and stable electrocatalytic response towards estradiol (E2) and progesterone (P4), the proposed sensor was able to distinguish two hormone's oxidation peaks clearly. Under the optimal conditions, for selective determination of E2, good linear relationships were obtained in the range of 0.001-6.0 mu mol L-1, with detection limit of 0.23 nmol L-1, and for P4 in the range of 0.001-6.0 mu mol L-1 with the detection limit of 0.31 nmol L-1. The prepared sensor possessed accurate and rapid response toward E2 and P4 with an improved stability, selectivity and repeatability. More importantly, the facile and environment-friendly electrochemical construction strategy provided here, may be open a cost-effective way for setting up nanocomposites or nanohybrid-based sensing platform, which extend the application of electrochemical sensor for the green, facile and sensitive analysis of electroactive compounds in biological systems and pharmaceutical formulations.