Molecular electrocatalysis at soft interfaces

The fundamental aspects of electrochemistry at liquid–liquid interfaces are introduced to present the concept of molecular electrocatalysis. Here, a molecular catalyst is adsorbed at the interface to promote a proton coupled electron transfer reaction such as hydrogen evolution or oxygen reduction using lipophilic electron donors

Component-resolved diagnostic of cow’s milk allergy by immunoaffinity capillary electrophoresis – matrix assisted laser desorption/ionization mass spectrometry

Component-resolved diagnostic (CRD) of cow’s milk allergy has been performed using immunoaffinity capillary electrophoresis (IACE) coupled with matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). First, total IgE quantification in the blood serum of a milk allergic patient by IACE-UV technique was developed using magnetic beads (MBs) coated with anti-human IgE antibodies (Abs) to perform the general allergy diagnosis. Then, the immunocomplex of anti-human IgE Abs with the patient IgE Abs, obtained during the total IgE analysis, was chemically cross-linked on the MBs surface. Prepared immunosupport was used for the binding of individual milk allergens to identify the proteins triggering the allergy by IACE with UV and MALDI MS detection. Then, allergy CRD was also performed directly with milk fractions. Bovine serum albumin, lactoferrin and α-casein (S1 and S2 forms, as was revealed by MALDI MS) were found to bind with the extracted IgE Abs, indicating that the chosen patient is allergic to these proteins. The results were confirmed by performing classical enzyme-linked immunosorbent assay of total and specific IgE Abs. The present IACE-UV/MALDI MS method required only 2 μl of blood serum and allowed the performance of the total IgE quantification and CRD of the food allergy not only with the purified allergen molecules, but also directly with the food extract. Such an approach opens the possibility for direct identification of allergens molecular mass and structure, discovery of unusual allergens, which could be useful for precise personalized allergy diagnostic, allergens epitope mapping and cross-reactivity studies

Bioanalytical methods for food allergy diagnosis, allergen detection and new allergen discovery

For effective monitoring and prevention of the food allergy, one of the emerging health problems nowadays, existing diagnostic procedures and allergen detection techniques are constantly improved. Meanwhile, new methods are also developed, and more and more putative allergens are discovered. This review describes traditional methods and summarizes recent advances in the fast evolving field of the in vitro food allergy diagnosis, allergen detection in food products and discovery of the new allergenic molecules. A special attention is paid to the new diagnostic methods under laboratory development like various immuno- and aptamer-based assays, including immunoaffinity capillary electrophoresis. The latter technique shows the importance of MS application not only for the allergen detection but also for the allergy diagnosis

Scan-Rate-Dependent Ion Current Rectification and Rectification Inversion in Charged Conical Nanopores

Herein we report a theoretical study of diode-like behavior of negatively charged (e.g., glass or silica) nanopores at different potential scan rates (1-1000 V center dot s(-1)). Finite element simulations were used to determine current-voltage characteristics of conical nanop ores at various electrolyte concentrations. This study demonstrates that significant changes in rectification behavior can be observed at high scan rates because the mass transport of ionic species appears sluggish on the time scale of the voltage scan. In particular, it explains the influence of the potential scan rate on the nanopore rectifying properties in the cases of classical rectification, rectification inversion, and the "transition" rectification domain where the rectification direction in the nanopore could be modulated according to the applied scan rate

Oxygen reduction at soft interfaces catalyzed by in situ-generated reduced graphene oxide

peer-reviewedFace to face: Flakes of reduced graphene oxide, synthesized in situ at the liquid/liquid interface from a graphene‐oxide precursor, are capable of catalyzing the biphasic reduction of protons to hydrogen peroxide in the presence of molecular oxygen and an organic solubilized electron donor. This offers a new perspective for the bulk production of a green oxidant through biphasic electrolysisACCEPTEDpeer-reviewe

Mediated water electrolysis in biphasic systems

peer-reviewedThe concept of efficient electrolysis by linking photoelectrochemical biphasic H2 evolution and water oxidation processes in the cathodic and anodic compartments of an H-cell, respectively, is introduced. Overpotentials at the cathode and anode are minimised by incorporating light-driven elements into both biphasic reactions. The concepts viability is demonstrated by electrochemical H2 production from water splitting utilising a polarised water-organic interface in the cathodic compartment of a prototype H-cell. At the cathode the reduction of decamethylferrocenium cations ([Cp2*Fe(III)]+) to neutral decamethylferrocene (Cp2*Fe(II)) in 1,2-dichloroethane (DCE) solvent takes place at the solid electrode/oil interface. This electron transfer process induces the ion transfer of a proton across the immiscible water/oil interface to maintain electroneutrality in the oil phase. The oil-solubilised proton immediately reacts with Cp2*Fe(II) to form the corresponding hydride species, [Cp2*Fe(IV)(H)]+. Subsequently, [Cp2*Fe(IV)(H)]+ spontaneously undergoes a chemical reaction in the oil phase to evolve hydrogen gas (H2) and regenerate [Cp2*Fe(III)]+, whereupon this catalytic Electrochemical, Chemical, Chemical (ECC’) cycle is repeated. During biphasic electrolysis, the stability and recyclability of the [Cp2*Fe(III)]+/Cp2*Fe(II) redox couple were confirmed by chronoamperometric measurements and, furthermore, the steady-state concentration of [Cp2*Fe(III)]+ monitored in situ by UV/vis spectroscopy. Post-biphasic electrolysis, the presence of H2 in the headspace of the cathodic compartment was established by sampling with gas chromatography. The rate of the biphasic hydrogen evolution reaction (HER) was enhanced by redox catalysis in the presence of floating catalytic molybdenum carbide (Mo2C) microparticles at the immiscible water/oil interface. The use of a superhydrophobic organic electrolyte salt was critical to ensure proton transfer from water to oil, and not anion transfer from oil to water, in order to maintain electroneutrality after electron transfer. The design, testing and successful optimisation of the operation of the biphasic electrolysis cell under dark conditions with Cp2*Fe(II) lays the foundation for the achievement of photo-induced biphasic water electrolysis at low overpotentials using another metallocene, decamethylrutheneocene (Cp2*Ru(II)). Critically, Cp2*Ru(II) may be recycled at a potential more positive than that of proton reduction in DCE