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• SnO 2 -doped Ag 2 O nanorods (NRs) were synthesized by wet-chemical method. • NRs were deposited onto GCE using 5% nafion chemical binder. • NRs sensor probe was exhibited the highest sensitivity and lowest LDR. • Validated of NRs/Nafion/GCE sensor probe with real bio-samples. • Safety of health and biomedical fields. Here, a reliable electrochemical sensor prove was fabricated by SnO 2 -doped Ag 2 O nanorods (NRs) decorated glassy carbon electrode (GCE) to detect choline (CA) in the buffer phase. The wet-chemically synthesized SnO 2 -doped Ag 2 O NRs were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) techniques respectively. SnO 2 -doped Ag 2 O NRs was layered as a film of NRs onto a GCE using Nafion adhesive to obtain the working electrode of the choline (CA) sensor. The proposed sensor is calibrated by using the concentration of CA versus measured current, which is found linear over a concentration range of CA (0.1 nM ~ 0.01 mM) defined as a dynamic range (LDR) for choline detection. Using LDR slope and the active surface of GCE (0.0316 cm2), the choline sensor sensitivity (95.1 µAµM-1cm−2) is calculated. The limit of detection (LOD) and limit of quantification (LOQ) of the proposed CA sensor are calculated using the signal-to-noise ratio at 3, and the obtained values are 95.9 ± 4.8 pM and 319.67 ± 5 pM respectively. The sensor reliability measuring parameters (response time, stability and reproducibility) are found satisfactory. In the end, the choline sensor with SnO 2 -doped Ag 2 O NRs/GCE is performed preciously in the electrochemical analysis of various real bio-samples to validate its real-time applicability. [ABSTRACT FROM AUTHOR]

• An electrochemical method for the determination of diethylstilbestrol was developed. • Fast response, low cost and convenient for batch preparation were distinctive features of the method. • The method was successfully applied to the detection of diethylstilbestrol in commercial livestock and poultry meats. A fast and simple electrochemical method for the determination of diethylstilbestrol (DES) was developed. Gold nanoparticles stabilized by chitosan (AuCS) were prepared and used in combination with L-cysteine (L-Cys) by self-assembly for fabricating the electrochemical sensors. Compared with unmodified electrode, the oxidation peak current of DES could be increased greatly by using the L-Cys/AuCS modified GCE (L-Cys/AuCS/GCE), indicating L-Cys/AuCS had excellent ability to promote electron transfer. Under the optimal conditions, the oxidation peak current was linear to the concentration of DES in the range from 5 × 10−7 to 1 × 10−4 mol/L (r = 0.997) with the detection limit of 1.7 × 10−7 mol/L (S/N = 3). The proposed method was successfully used for the determination of DES in livestock and poultry meats with the satisfying recovery results (75.3–91.9%). The method not only exhibited good accuracy and reproducibility for DES detection, but also had the advantages of low cost, simple preparation method and convenient for batch preparation. [ABSTRACT FROM AUTHOR]

• Germanium-doped zinc oxide composite nanoparticles was prepared. • A fast response and high selectivity toward 4-Aminophenol were realized. • Exhibited sensor sensitivity was 0.5063 µA cm−2 µM−1. • Found sensor lowest detection limit was 0.5925 ± 0.02 nM. • Safety of environment and healthcare fields. The present study aims to fabricate and investigate the germanium-doped zinc oxide (Ge/ZnO) composite nanoparticles (NPs) coated gassy carbon electrode (GCE) sensor by electrochemical method. The performances including sensitivity, stability, lower detection limit, reliability, and reproducibility were evaluated in details at room conditions. Electrochemical method was employed to deposit Ge/ZnO NPs on flat GCE in the presence of 5% nafion (conducting binders) for fabricating the sensor matrix, which exhibited the fast response towards hazardous 4-Aminophenol (4AP) chemical. UV/vis, FT-IR, EDS, XRD, FESEM, and XPS were used to characterize the prepared Ge/ZnO NPs. Electrochemical method is employed to investigate the current response in detecting 4AP chemical at room conditions. Results show that the current response of Ge/ZnO NPs coated GCE sensor precisely changes, which directly depended on the target concentration as well as the type of the target analyte existed in solution. The sensitivity and detection limit are calculated from the slope of calibration curve by considering the active surface area of fabricated electrode, which are found as 0.5063 µA cm−2 µM−1 and 0.5925 ± 0.02 nM respectively. The measured performances are found to be good and in some cases, better than those of other sensor materials reported in literatures. The developed chemical sensors could be efficiently applied to detect the phenolic derivatives for green environment by ensuring safety in broader scales. [ABSTRACT FROM AUTHOR]

• A simple analytical method for the determination of DNA nucleobases. • Enhanced sensitivity for electrochemical detection using PANI-MoS 2 /CPE. • The effects of supporting electrolyte, concentration, and pH were investigated. • Low limit of detection of the electrochemical biosensor with favorable R2. Robust detection of DNA as a molecule that encodes genetic instructions is getting significant attention in recent years due to its promising applications in diseases diagnosis and treatment, forensic analysis, food safety evaluation, environmental monitoring, and so on. In this research, a simple, rapid and multiplex electrochemical method based on single-layer molybdenum disulfide (MoS 2) nanosheets sensing platform and differential pulse voltammetry (DPV) method for detection of DNA nucleobases (DNANBs) was set up without any pretreatment or separation process. Hence, the carbon paste electrode modified with MoS 2 (MoS 2 /CPE) was selected, and the effects of different parameters such as supporting electrolyte composition and pH were optimized to obtain the best peak potential separation and high sensitivity. Then, the individual, respective and simultaneous determinations of DNANBs were performed by controlling the certain experimental conditions. The results exhibited the excellent sensitivity, low limit of detection, and high selectivity of the electrochemical biosensor. Moreover, the peak current values were linearly dependent on the concentration of DNANBs. For comparison, common methods for determination of DNANBs were analyzed based on the absorption of ultraviolet light and Raman spectroscopy. Finally, the proposed electrode was modified with polyaniline (PANI-MoS 2 /CPE) as a new biosensor for the determination of DNANBs, exhibiting good reproducibility and stability. [ABSTRACT FROM AUTHOR]