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.

A novel ECL sensor based on a boronate affinity molecular imprinting technique and functionalized SiO2@CQDs/AuNPs/MPBA nanocomposites for sensitive determination of alpha-fetoprotein.

In this work, a boronate-affinity sandwich electrochemiluminescence (ECL) sensor was constructed to detect alpha-fetoprotein (AFP) based on a multiple signal amplification strategy. Gold nanoparticles (AuNPs) were utilized and modified on the surface with chitosan in order to facilitate electron transfer. The composite of the molecularly imprinted polymer (MIP) enhanced the selectivity of alpha-fetoprotein detection. 4-mercaptophenylboronic acid (MPBA) was used as the tracing tag for capture of alpha-fetoprotein. SiO2 nanoparticles carried carbon quantum dots (CQDs) labeled with gold nanoparticles and produced an ECL signal. Under the optimum experimental conditions, the linear range for alpha-fetoprotein was between 0.001 and 1000 ng/mL with a correlation coefficient of 0.9952, and the detection limit was 0.0004 ng/mL (S/N = 3). This proposed ECL sensor displayed several advantages, including outstanding selectivity, fine reproducibility, high sensitivity, low detection limit and wide linear range. Furthermore, the newly constructed boronate-affinity sandwich ECL sensor was successfully applied to the determination of alpha-fetoprotein in serum samples, indicating great potential for application in clinical diagnostics.