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A novel electrochemical detection method based on a nickel ferrite@graphene (NiFe2O4@Gr) nanocomposite-containing molecularly imprinted polymer (MIP) was developed for the sensitive determination of butylated hydroxyanisole (BHA). After successful completion of the nanocomposite production under hydrothermal conditions, the NiFe2O4@Gr nanocomposite and a novel molecularly imprinted sensor based on the NiFe2O4@Gr nanocomposite were characterized using microscopic, spectroscopic and electrochemical techniques. According to the characterization results, the synthesis of the core–shell type NiFe2O4@Gr nanocomposite with high purity and efficiency has been proved to be successful. After successful modification of a cleaned glassy carbon electrode (GCE) with the NiFe2O4@Gr nanocomposite, analytical applications were started with the prepared BHA printed GCE. This novel molecularly imprinted electrochemical sensor for BPA detection demonstrated a linearity of 1.0 × 10−11–1.0 × 10−9 M and a low detection limit (LOD, 3.0 × 10−12 M). In addition, the BHA imprinted polymer based on the NiFe2O4@Gr nanocomposite also exhibited excellent selectivity, stability, reproducibility and reusability performances in flour analysis. [ABSTRACT FROM AUTHOR]

The accurate and precisive monitoring of aflatoxin B1 (AFB1), which is one of the most hazardous mycotoxins, especially in agricultural products, is significant for human and environmental health. AFB1 generally contaminates agricultural products such as corn and feedstuff. In this paper, a novel electrochemical AFB1 immunosensor was constructed based on Ag nanocubes (AgNCs) incorporated trigonal metallic MoS2 nanosheets with 1T phase (AgNCs/1T-MoS2) as signal amplification and gold nanoparticles/porous graphene nanoribbon (AuNPs/PGNR) as an electrochemical sensor platform. First, the chronoamperometry method was implemented to provide electrodeposition of AuNPs on PGNR following chemical reduction of PGNR. Immobilization of the primer AFB1 antibody was performed via amino-gold affinity between primer antibody and AuNPs/PGNR composite. Subsequently, the conjugation of seconder antibody to AgNCs/1T-MoS2 was performed by strong π–π and electrostatic interactions. To describe the surface morphology and elemental composition of the prepared electrochemical AFB1 immunosensor, physicochemical characterization techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) were used. Furthermore, cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) techniques were used to evaluate the immunosensor's electrochemical performance. The developed electrochemical AFB1 immunosensor offered a good sensitivity with a detection limit (LOD) of 2.00 fg mL−1. Finally, an electrochemical AFB1 immunosensor with satisfactory selectivity, stability and reusability was applied in wheat samples with high recovery. [ABSTRACT FROM AUTHOR]

Biomass-derived carbonaceous materials have been deemed to be one of the up-and-coming electrode materials for high-performance energy storage systems due to their cost-neutral abundant resources, sustainable nature, easy synthesis methods, and environmentally benign features. In this work, various graphene-like porous carbon networks (GPCs) with three-dimensional (3D) hierarchically ordered "ion highways" have been synthesized by the carbonization/activation of orange-peel wastes for use as an electrode material in high-energy supercapacitors. The porous structures and surface morphologies of the GPCs were rationally fine-tuned as a function of the activation agent ratio. The prepared GPCs offered superior specific surface area in addition to a 3D porous structure with a fine-tuned pore size distribution. The electrochemical behaviors of all the GPCs were evaluated in 6.0 M KOH aqueous electrolyte via a three-electrode electrochemical setup. Owing to their synergistic characteristics, including superior specific surface area (1150 m2 g−1), large pore volume, and fine-tuned 3D porous architecture, GPC-3.0 (synthesized with a KOH : GPC ratio of 3.0, by wt.) exhibited the best capacitive behavior amongst the studied GPCs. The 3D hierarchically ordered architecture acts like well-designed ion highways that boost electron transportation, thereby enhancing electrochemical energy storage. A coin-cell-type symmetrical supercapacitor based on GPC-3.0 was tested in both 1.0 M Na2SO4 (salt-in-water) and 12.0 m NaNO3 (water-in-salt) electrolytes. The supercapacitor cell based on the water-in-salt electrolyte offered a wide operating voltage of 2.3 V. The obtained energy density and power density values were comparable to those of commercial high-performance electrical double-layer capacitors. Such notable findings will shed light on next-generation high-rate electrochemical energy storage systems based on biomass-derived carbonaceous materials. [ABSTRACT FROM AUTHOR]

Chlorpyrifos (CHL) is one of the most frequently used broad-spectrum organophosphate insecticides. Especially, its incorrect and uncontrolled usage cause public concern about food and environment safety. In this report, a new molecularly imprinted quartz crystal microbalance (QCM) sensor on delaminated sulfur-doped MXene (d-S-Ti3C2TX MXene) was prepared for CHL. The structures of the bare MAX phase (Ti3AlC2), sulfur-doped MAX phase (S-Ti3AlC2), wrinkled sulfur-doped MXene (S-Ti3C2TX MXene) and d-S-Ti3C2SX MXene were highlighted by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and X-ray diffraction (XRD). The CHL imprinted QCM sensor was prepared in the presence of MAGA and CHL in 2 : 1 molar ratio. From the analytical results 1.0 × 10−12–1.0 × 10−10 M and 3.0 × 10−13 M were found to be the linearity range and detection limit (LOD), respectively. Furthermore, the CHL imprinted QCM sensor was examined in terms of stability, repeatability, reproducibility and reusability. Finally, the imprinted sensor was applied to orange juice samples, and a high recovery was obtained. [ABSTRACT FROM AUTHOR]