Based on reduced graphene oxide-copper sulfide-carbon nitride nanosheets composite electrochemiluminescence sensor for determination of gatifloxacin in mouse plasma.

A new method for determination of gatifloxacin hydrochloride (GAT) by reduced graphene oxide-copper sulfide (rGO-CuS) composite coupled with graphite-like carbon nitride nanosheets (g-C3N4 NSs) modified glassy carbon electrode was developed. In this work, rGO-CuS composite was synthesized by one-pot hydrothermal method and used for enhancing sensitivity of GAT. g-C3N4 NSs were synthesized as radiant agent. The sensor characteristics of electrochemistry and electrochemiluminescence (ECL) were investigated. The ECL intensity has enhanced four-fold after modifying with rGO-CuS composite. The results can be ascribed to the presence of rGO-CuS composite on the electrode surface that facilitates the electron transfer rate between the electroactive center of g-C3N4 NSs and the electrode. Under the optimum experimental conditions (photomultiplier tuber for 800 V, scan rate for 0.1 V/s, 0.1 mol/L PBS (pH 7.5) and 1.0 × 10-2 mol/L K2S2O8), the linear range for GAT was from 1.0 × 10-4 to 1.0 × 10-8 mol/L (R2 = 0.9991) with detection limit of 3.5 × 10-9 mol/L (S/N = 3). RSD for ECL intensity was 4.8% (n = 10). The recoveries of GAT in mouse plasma samples were from 98.36 to 104.7%. The sensor showed the advantages of low cost, high sensitivity and wide application in drug analysis.