Development of a photoelectrochemical sensor for detection of TBHQ antioxidant based on LiTCNE-TiO2 composite under visible LED light

Highly Sensitive Electrochemical Determination of Butylated Hydroxyanisole in Food Samples Using Electrochemical-Pretreated Three-Dimensional Graphene Electrode Modified with Silica Nanochannel Film

The sensitive detection of antioxidants in food is essential for the rational control of their usage and reducing potential health risks. A simple three-dimensional (3D) electrode integrated with an anti-fouling/anti-interference layer possesses great potential for the direct and sensitive electrochemical detection of antioxidants in food samples. In this work, a 3D electrochemical sensor was developed by integrating a 3D graphene electrode (3DG) with vertically ordered mesoporous silica film (VMSF), enabling highly sensitive detection of the common antioxidant, butylated hydroxyanisole (BHA), in food samples. A simple electrochemical polarization was employed to pre-activate the 3DG electrode (p3DG), enhancing its hydrophilicity. Using the p3DG as the supporting electrode, stable modification of VMSF was achieved using the electrochemical assisted self-assembly (EASA) method, without the need for any adhesive agents (VMSF/p3DG). Taking BHA in food as a model analyte, the VMSF/p3DG sensor demonstrated high sensitivity, due to the enrichment by nanochannels, towards BHA. Electrochemical detection of BHA was achieved with a linear range of 0.1 μM to 5 μM and from 5 μM to 150 μM with a low limit of detection (12 nM). Owing to the fouling resistance and anti-interference capabilities of VMSF, the constructed 3D electrochemical sensor can be directly applied for the electrochemical detection of BHA in complex food samples.

Alarming impact of the excessive use of tert-butylhydroquinone in food products: A narrative review

Tert-butyl hydroquinone (TBHQ) is a food additive commonly used as a more effective protectant in the food, cosmetic and pharmaceutical industries. However, the long-term exposure to TBHQ at higher doses (0.7 mg/kg) results in substantial danger to public health and brings a series of side effects, including cytotoxic, genotoxic, carcinogenic, and mutagenic effects. As a result, the global burden of chronic diseases has fascinated consumers and governments regarding the safety assessment of food additives. Regarding contradictory reports of various research about the application of food additives, the accurate monitoring of food additives is urgent. Notwithstanding, there are reports of the therapeutic effects of TBHQ under pathologic conditions through activation of nuclear factor erythroid 2-related factor 2. Thus, further investigations are required to investigate the impact of TBHQ on public health and evaluate its mechanism of action on various organs and cells. Therefore, this review aimed to investigate TBHQ safety through an overview of its impacts on different tissues, cells, and biological macromolecules as well as its therapeutic effects under pathologic conditions.

Porous carbon derived from ZIF-8 modified molecularly imprinted electrochemical sensor for the detection of tert-butyl hydroquinone (TBHQ) in edible oil

In this manuscript, ZIF-8 derived nanoporous carbon material (ZC) was prepared and used as modification material to construct a molecularly imprinted electrochemical sensor for the direct detection of tert-butyl hydroquinone (TBHQ) in edible oil. Electrochemical characterizations, scanning electron microscopy and X-ray diffraction show that ZC has excellent conductivity, high electrochemical active area and stable porous framework structure. Using TBHQ as template and o-phenylenediamine as functional monomer, the sensor was constructed. Experimental parameters such as the number of polymerization cycle, polymerization speed, and pH of the measured solution, removal and rebinding time were studied. Under optimized conditions, the prepared sensor showed a wider linear range from 1.0 μmol L^-1 to 75.0 μmol L^-1 with the detection limit of 0.42 μmol L^-1 (S/N = 3). Meanwhile, the sensor also expressed good selectivity, repeatability, reproducibility, stability and successfully applied for the determination of TBHQ in real edible oil, giving satisfactory results.

A photoelectrochemical immunosensor based on gold nanoparticles/ZnAgInS quaternary quantum dots for the high-performance determination of hepatitis B virus surface antigen

ZnAgInS quaternary quantum dots were prepared using glutathione as the capped reagent. Gold nanoparticles (GNPs) were integrated with ZnAgInS QDs to provide a GNPs/ZnAgInS QDs nanocomposite. The morphological image, component and crystal structure of GNPs/ZnAgInS QDs were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). A glassy carbon electrode surface was coated with GNPs/ZnAgInS QDs nanocomposites to construct an interface for immobilizing the antibody of hepatitis B virus surface antigen (anti-HBsAg). By employing GNPs/ZnAgInS QDs as a photoactive element, a photoelectrochemical immunosensor for hepatitis B virus surface antigen (HBsAg) was developed. The results indicate that gold nanoparticles can dramatically enhance the photocurrent response of ZnAgInS QDs and thus improving the sensing performances of the immunosensor. The experimental conditions including incubation time, incubation temperature, and ascorbic acid concentration were optimized. The relative photocurrent decline [R_i = ΔI/I₀= (I₀ - I)/I₀] shows a linear relationship to the logarithm of HBsAg concentration [lg(c, ng mL^-1)] in the range from 0.005 to 30 ng mL^-1. A detection limit of 0.5 pg mL^-1 was obtained. The immunosensor shows excellent sensitivity, selectivity, stability and reproducibility. The HBsAg concentrations in clinical serum samples were also accurately determined with this new photoelectrochemical immunosensor.

Three-Dimensional Printed Electrode and Its Novel Applications in Electronic Devices

Three-dimensional (3D) printing technology provides a novel approach to material fabrication for various applications because of its ability to create low-cost 3D printed platforms. In this study, a printable graphene-based conductive filament was employed to create a range of 3D printed electrodes (3DEs) using a commercial 3D printer. This printing technology provides a simplistic and low-cost approach, which eliminates the need for the ex-situ modification and post-treatment of the product. The conductive nature of the 3DEs provides numerous deposition platforms for electrochemical active nanomaterials such as graphene, polypyrrole, and cadmium sulfide, either through electrochemical or physical approaches. To provide proof-of-concept, these 3DEs were physiochemically and electrochemically evaluated and proficiently fabricated into a supercapacitor and photoelectrochemical sensor. The as-fabricated supercapacitor provided a good capacitance performance, with a specific capacitance of 98.37 Fg⁻¹. In addition, these 3DEs were fabricated into a photoelectrochemical sensing platform. They had a photocurrent response that exceeded expectations (~724.1 μA) and a lower detection limit (0.05 μM) than an ITO/FTO glass electrode. By subsequently modifying the printing material and electrode architecture, this 3D printing approach could provide a facile and rapid manufacturing process for energy devices based on the conceptual design.

Cation Dependence of the Dimerization Enthalpy for A2 [tetracyanoethylene]2 (A=NMe4 , Mepy, NEt4 ) Possessing a Long, Multicenter Bond

[TCNE]^.- (TCNE=tetracyanoethylene) has been isolated as D_2h π-[TCNE]₂^2- possessing a long, 2.9 Å multicenter 2-electron-4-center (2e^- /4c) C-C bond, and as C₂ π-[TCNE]₂^2- possessing a longer, 3.04 Å multicenter 2e^- /6c (4 C+2 N atoms) bond. Temperature-dependent UV/Vis spectroscopic measurements in 2-methyltetrahydrofuran (MeTHF) has led to the determination of the dimerization, 2[TCNE]^.- ⇌π-[TCNE]₂^2- , equilibrium constants, K_eq (T), [[TCNE]₂^2- ]/[[TCNE]^.- ]² , enthalpy, ΔH, and entropy, ΔS, of dimerization for [Mepy]₂ [TCNE]₂ (Mepy=N-methylpyridinium, H₃ CNC₅ H₅⁺ ) possessing D_2h π-[TCNE]₂^2- and [NMe₄ ]₂ [TCNE]₂ possessing C₂ π-[TCNE]₂^2- conformations in the solid state; however, both form D_2h π-[TCNE]₂^2- in MeTHF solution. Based on ΔH=-3.6±0.1 kcal mol^-1 (-15.2 kJ mol^-1 ), and ΔS=-11±1 eu (-47 J mol^-1  K^-1 ) and ΔH=-2.4±0.2 kcal mol^-1 (-10.2 kJ mol^-1 ), and ΔS=-8±1 eu (-32 J mol^-1  K^-1 ) in MeTHF for [NMe₄ ]₂ [TCNE]₂ and [Mepy]₂ [TCNE]₂ , respectively, the calculated K_eq (298 K) are 1.6 and 1.3 m^-1 , respectively. The observed K_eq (145 K) are 3 and 2 orders of magnitude greater for [NMe₄ ]₂ [TCNE]₂ and [Mepy]₂ [TCNE]₂ , respectively. The K_eq (130 K) is 4470, 257, ≈0.8, and ≪0.1 m^-1 for [NMe₄ ]₂ [TCNE]₂ , [Mepy]₂ [TCNE]₂ , [NEt₄ ]₂ [TCNE]₂ , and [N(nBu)₄ ]₂ [TCNE]₂ , respectively, decreasing with increasing cation size. At standard conditions and below ambient temperature the equilibrium favors the dimer for the NMe₄⁺ and Mepy⁺ cations. From the decreasing enthalpy, NMe₄⁺ >Mepy⁺ , along with the decrease in dimer formation K_eq (T) as NMe₄⁺ >Mepy⁺ >NEt₄⁺ >N(nBu)₄⁺ , the dimer bond energy decreases with increasing cation size in MeTHF. This is attributed to a decrease in the [A]⁺ ⋅⋅⋅[TCNE]^- attractive interactions with increasing cation size. Solid state UV/Vis spectroscopic determinations of [NMe₄ ]₂ [TCNE]₂ are reported and compared to D_2h π-[TCNE]₂^2- conformers. The feasibility and limitations of temperature-dependent electron paramagnetic resonance (EPR) measurements for the determination of K_eq (T) are also discussed.