A simple and sensitive electrochemical immunosensor for bisphenol A was prepared with an acetylene black–chitosan–gold composite (AB–CS–Au) and gold nanoparticles (AuNPs) as electrode modifiers and chlorogenic acid (CGA) as the redox probe. AB–CS–Au acted as a signal amplifier and anti-BPA was immobilized at the modified electrode using AuNPs to capture bisphenol A in a sample solution. After some factors such as pH of the supporting electrolyte and immunoreaction time were optimized, a quantitative detection of bisphenol A was established in the range of 7.5 × 10−9−1.0 × 10−6 M with a limit of detection (LOD) and quantitation (LOQ) of 6.4 × 10−9 M (3 σ/k) and 2.1 × 10−8 M (10 σ/k), respectively. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were applied to characterize the construction procedures of the immunosensor. The ascribed immunosensor yielded good results in terms of specificity, stability and reproducibility and was successfully applied to sample analysis with accuracy.

•A simple and label-free immunosensor of bisphenol A was fabricated.•MWCNTs and AuNPs were introduced to enhance current response.•Rutin was used as the redox probe to construct bisphenol A immunosensor.•The proposed method was applied in bisphenol A detection in food fresh-keeping film.In this work, a new and label-free electrochemical immunosensor for sensitive detection of bisphenol A was reported. MWCNTs and gold nanoparticles (AuNPs) were modified on glassy carbon electrode surface to enhance current response. The Anti-BPA was immobilized on the modified electrode through AuNPs. Rutin was used for the first time as the redox probe to construct electrochemical immunosensor of bisphenol A. The peak current change due to the specific immuno-interaction between anti-BPA and BPA on the modified electrode surface was utilized to detect bisphenol A. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) were employed to trace the assembly process of the electrochemical immunosensor. Experimental factors affecting the sensitivity of the immunosensor were examined in terms of incubation time and pH of phosphate buffer solution (PBS). Under optimized conditions, the linear range of calibration curve based on the relationship between current response and BPA concentration was from 1.0×10−8–1.0×10−6 M with detection limit of 8.7×10−9 M (S/N=3). The proposed immunosensor showed good reproducibility, selectivity, stability and was successfully applied to the determination of BPA in real sample.

•Indirect detection of glutathione based on rutin as a mediator.•High performance acetylene black/graphite composite electrode was fabricated.•Sensitive glutathione sensor was developed.The electrocatalytic oxidation of glutathione based on rutin as a mediator was studied at acetylene black (AB) modified carbon paste electrode (CPE). The results of cyclic voltammetric experiments showed that rutin could catalyze oxidation of GSH in PBS (pH 7.0) and the oxidation current was greatly increased by using AB-CPE compared to the nonmodified CPE. The kinetic parameters such as catalytic rate constant and diffusion coefficient were obtained using double potential step chronoamperometry. Under the optimum conditions, the electrocatalytic oxidation peak current was linear to the glutathione concentration range from 0.5 μM to 3.5 μM and 2.5 μM to 25 μM with the detection limit of 0.080 μM (S/N = 3) by differential normal pulse voltammetry (DNPV). The proposed method has been applied to the determination of glutathione in pharmaceutical sample with satisfactory results.

In this paper, a sensitive graphite/poly(methyl methacrylate) (PMMA) composite electrode was firstly applied to the determination of o-sec-butylphenol (osBP). This polymer carbon paste electrode (CPE) effectively improved the soft surface of traditional CPE, and enhanced the sensitivity and reproducibility. Factors influencing detection processes were optimized and kinetic parameters were calculated. Under the optimal conditions, the amperometric current density was linear with the concentration of osBP in the range from 2.50 × 10−7 to 3.55 × 10−5 mol L−1 and the detection limit was 3.48 × 10−8 mol L−1. The proposed method was successfully used to determine osBP in greengrocery samples and satisfactory results were obtained.