Sensitive and Simultaneous Electrochemical Sensing for Three Dihydroxybenzene Isomers Based on Poly(L-arginine) Modified Glassy Carbon Electrode

A Highly Selective Electrochemical Sensor Based on Molecularly Imprinted Copolymer Functionalized with Arginine for the Detection of Chloramphenicol in Honey

Developing an efficient method for chloramphenicol (CAP) detection is of great significance for food safety. Arginine (Arg) was selected as a functional monomer. Benefiting from its excellent electrochemical performance, which is different from traditional functional monomers, it can be combined with CAP to form a highly selective molecularly imprinted polymer (MIP) material. It overcomes the shortcoming of poor MIP sensitivity faced by traditional functional monomers, and achieves high sensitivity detection without compounding other nanomaterials, greatly reducing the preparation difficulty and cost investment of the sensor. The possible binding sites between CAP and Arg molecules were calculated by molecular electrostatic potential (MEP). A low-cost, non-modified MIP electrochemical sensor was developed for the high-performance detection of CAP. The prepared sensor has a wide linear range from 1 × 10^-12 mol L^-1 to 5 × 10^-4 mol L^-1, achieves a very low concentration CAP detection, and the detection limit is 1.36 × 10^-13 mol L^-1. It also exhibits excellent selectivity, anti-interference, repeatability, and reproducibility. The detection of CAP in actual honey samples was achieved, which has important practical value in food safety.

Picomolar level electrochemical detection of hydroquinone, catechol and resorcinol simultaneously using a MoS2 nano-flower decorated graphene

A Graphene-Molybdenum disulphide nanocomposite was developed for the simultaneous electrochemical detection of dihydroxy benzene isomers attributed to the structural aspects.

Based on Gold Nanoparticles-L-Tyr-Amino Functionalized Mesoporous Materials-Polyphenol Oxidase Modified Biosensor for the Detection of Resorcinol

Nowadays, resorcinol (RC) has been widely applied in the chemical and pharmaceutical industries. However, the electrochemical detection technique of RC still features some significant drawbacks, for instance, a low sensitivity. Hence, in the present work, a glass carbon electrode was developed for the electrochemical detection of RC with good specificity and stability, through modifying the glass carbon electrode (GCE) by polyphenol oxidase (PPO), an NH₂-SBA-15 mesoporous material (NH₂-SBA-15), L-tyrosine (L-Tyr) and gold nano-particles (AuNPs). After being successively modified by AuNPs, L-Tyr, NH₂-SBA-15 and PPO, the constructed PPO/NH₂-SBA-15/L-Tyr/AuNPs/GCE was used to discriminate RC from ions and other common micromolecules, which showed a fairly good specificity and stability. The proposed electrochemical detection method features a linear range of from 0.5 to 21.0 μM with a LOD down to 0.15 μM, revealing a better sensitivity than the existing methods. It is worth mentioning that the proposed PPO/NH₂-SBA-15/L-Tyr/AuNPs/GCE has been successfully used as an electrochemical probe for the RC assay in domestic sewage.

3-Aminobenzeneboronic Acid Functionalized MoS2 Quantum Dot as Fluorescent Nanoprobe for the Determination of o-Dihydroxybenzene

In this work, by functionalizing MoS₂ quantum dot with 3-aminobenzeneboronic acid, a novel multifunctional quantum dot (denoted as B-MoS₂ QD) was obtained and used successfully for a fluorescence nanoprobe for detecting o-dihydroxybenzene (o-DHB). Transmission electron microscopy, fluorescence spectrum, UV-vis spectrum and fluorescence lifetime were used to investigate the prepared nanoprobe. The results show that the B-MoS₂ QD nanoprobe can exhibit strong fluorescence and excellent light fastness owing to the coupled effect from the MoS₂ QDs and boronic acid; interestingly, the vicinal diols structure from its surface can bridge covalently with o-DHB, resulting in the fluorescence quenching of B-MoS₂ QDs and selective recognition toward o-DHB. With the increasing of o-DHB concentration, the nanoprobe fluorescence would gradually decrease. By measuring the fluorescence intensity of B-MoS₂ QDs, a wide linear range from 0.1 to 200.0 μM with a low detection limit of 0.025 μM was obtained for o-DHB analysis; meanwhile, this fluorescence nanoprobe possesses excellent selectivity for the selective detection of o-DHB from its analogues.

Sensitive Detection of Caffeic Acid and Rutin via the Enhanced Anodic Electrochemiluminescence Signal of Luminol

The electrooxidation of phenolic groups of caffeic acid and rutin promote anodic electrochemiluminescence (ECL) luminol substantially. A sensitive, and cost-effective ECL method has thus been developed to detect caffeic acid, ranging from 0.1 to 5.0 μM, with a detection limit of 0.1 μM and rutin ranging from 0.2 to 25 μM with a detection limit of 0.12 μM. Contrarily, phenolic compounds quench the weak cathodic ECL of luminol. Both of anodic and cathodic ECL mechanisms of luminol in the presence of phenolic compounds are analyzed. The method based on the boomed anodic ECL of luminol is comparable to those based on Ru(bpy)₃²⁺ and S₂O₈^2-/O₂ systems. A lower onset potential and price than the other ECL reagents would realize its widely applications in the detection of phenolic compounds in food and medicine.