An electrochemiluminescence sensor based on CsPbBr3 -zquantum dots and poly (3-thiophene acetic acid) cross-linked nanogold imprinted layer for the determination of benzo(a)pyrene in edible oils

An electrochemical sensor based on electrochemically activated carbon cloth and poly (o-aminothiophenol) cross-linked nanogold imprinted layer for the determination of tert-butylhydroquinone

In this study, an electrochemical sensor based on MoS2 with enhanced electrochemical signals from electrochemically activated carbon cloth (EACC) electrodes and cross-linked o-aminothiophenol functionalized AuNPs (o-ATP@AuNPs) was developed for the detection of the unsaturated vegetable oil antioxidant tert-butylhydroquinone (TBHQ). In this approach, carbon cloth is activated through the implementation of electrochemical methods, thereby effectively increasing its specific surface area. The resulting EACC, serving as an electrode substrate, enables the growth of additional nanomaterials and enhances conductivity. The incorporation of MoS2 effectively augments the sensitivity of the electrochemical sensor. Subsequently, MIP/MoS2/EMCC is formed via electropolymerization, utilizing TBHQ as the template molecule and o-ATP@AuNPs as the functional monomer. The SS bond of o-ATP ensures a strong and stable connection between MoS2 and o-ATP@AuNPs, thereby facilitating the immobilization of MIP. In addition, the high conductivity possessed by o-ATP@AuNPs could effectively improve the sensitivity of the electrochemical sensor. Under the optimal conditions, MIP/MoS2/EMCC could determine TBHQ in the range of 1 × 10-3 μM to 120 μM by differential pulse voltammetry (DPV) with a detection line of 0.72 nM. The proposed MIP/MoS2/EMCC is expected to be applied in the future for the selective and sensitive detection of TBHQ in vegetable oils.

CsPbBr3 NCs Confined and In Situ Grown in ZIF-8: A Stable, Sensitive, Reliable Fluorescent Sensor for Evaluating the Acid Value of Edible Oils

Rapidly and sensitively evaluating the acid value (AV) of edible oils is significant to ensuring food quality and safety. Cesium lead bromide perovskite nanocrystals (CsPbBr3 NCs) are an effective candidate for AV detection; however, their instability restricts wide applications. Herein, CsPbBr3@ZIF-8 was prepared by confining and growing CsPbBr3 NCs in situ into zeolitic imidazolate framework-8 (ZIF-8) to improve the stability, and a fluorescence sensor was established to evaluate the AV of edible oils. The results present that CsPbBr3 NCs (below 5 nm) with excellent optical properties were confined and grown in situ in micropores and mesopores of ZIF-8. Meanwhile, CsPbBr3@ZIF-8 had better long-term storage, ultraviolet-irradiation, and water-exposure stabilities, compared with CsPbBr3 NCs. Given the fact that free fatty acids (the major contributor of AV) decrease the fluorescence of CsPbBr3 NCs, the fluorescence intensities of CsPbBr3@ZIF-8 were negative-linearly related to oil AV (R2 = 0.9902) in 0.04-6.00 mg of KOH/g with a 0.06 mg of KOH/g limit of detection. Besides, the practical AV recovery was 92-101% with an average relative standard deviation of 2%. Furthermore, the detection time was 20 min. The response mechanism revealed that free fatty acids could remove surface ligands and increase surface defects to prompt the aggregation of CsPbBr3 NCs and the formation of lattice fringe dislocations, inducing a decrease in the fluorescence. Thus, a stable, sensitive, reliable sensor was established to evaluate the AV of edible oils.

Perovskite Nanocrystals: Superior Luminogens for Food Quality Detection Analysis

With the global limited food resources receiving grievous damage from frequent climate changes and ascending global food demand resulting from increasing population growth, perovskite nanocrystals with distinctive photoelectric properties have emerged as attractive and prospective luminogens for the exploitation of rapid, easy operation, low cost, highly accurate, excellently sensitive, and good selective biosensors to detect foodborne hazards in food practices. Perovskite nanocrystals have demonstrated supreme advantages in luminescent biosensing for food products due to their high photoluminescence (PL) quantum yield, narrow full width at half-maximum PL, tunable PL in the entire visible spectrum, easy preparation, and various modification strategies compared with conventional semiconductors. Herein, we have carried out a comprehensive discussion concerning perovskite nanocrystals as luminogens in the application of high-performance biosensing of foodborne hazards for food products, including a brief introduction of perovskite nanocrystals, perovskite nanocrystal-based biosensors, and their application in different categories of food products. Finally, the challenges and opportunities faced by perovskite nanocrystals as superior luminogens were proposed to promote their practicality in the future food supply.

Chemical Sensors Based on Covalent Organic Frameworks

Covalent organic frameworks (COFs) are a type of crystalline porous polymer composed of light elements through strong covalent bonds. COFs have attracted considerable attention due to their unique designable structures and excellent material properties. Currently, COFs have shown outstanding potential in various fields, including gas storage, pollutant removal, catalysis, adsorption, optoelectronics, and their research in the sensing field is also increasingly flourishing. In this review, we focus on COF-based sensors. Firstly, we elucidate the fundamental principles of COF-based sensors. Then, we present the primary application areas of COF-based sensors and their recent advancements, encompassing gas, ions, organic compounds, and biomolecules sensing. Finally, we discuss the future trends and challenges faced by COF-based sensors, outlining their promising prospects in the field of sensing.