Molybdenum-modified platinum electrodes

The modification of Pt electrodes with Mo compounds improves their catalytic activity toward the oxidation of methanol and formaldehyde in acidic solutions. The two sets of Mo oxides that have been studied in this work are the Hydrogen Molybdenum Bronze, HₓMoO₃, 0<x<2, and the Molybdenum Oxides, MoOₓ, 2<x<3. -- It has been found that the bronze (H₂MoO₃)ads is generated at the Pt surface in an in situ fashion upon the application of potentials more negative than 0 vs. Ag/AgCl. At higher positive potentials, the adsorbed bronze is oxidized to several intermediates that interact with methanol and facilitate its oxidation on the Pt surface. The nature of the interaction between the adsorbed intermediates and methanol needs further experimental investigation. -- The deposition of MoO₃ on the surface of a commercial carbon supported Pt catalyst, has been achieved. The catalytic promotion observed with the modified catalyst over its unmodified counterpart has been explained in terms of the bi-functional mechanism introduced by Watanabe and Motoo. The activity of the Mo modified catalyst increases with the elevation of the MoO₃ surface concentration to a certain limit, then it decreases with further Mo addition. The extra MoO₃ content shields the Pt sites from the methanol or the formaldehyde molecules. In addition, it is added at the expense of the carbon content of the catalyst that is required for the electronic conductivity through the modified electrode

Low Cost Lab on Chip for the Colorimetric Detection of Nitrate in Mineral Water Products

The diagnostics of health status and the quality of drinking water are among the most important United Nations sustainable development goals. However, in certain areas, wars and instability have left millions of people setting in refugee camps and dangerous regions where infrastructures are lacking and rapid diagnostics of water quality and medical status are critical. In this work, microfluidic testing chips and photometric setups are developed in cheap and portable way to detect nitrate concentrations in water. The performed test is designed to work according to the Griess procedure. Moreover, to make it simple and usable in areas of low resource settings, commercially available Arduino mega and liquid crystal display (LCD) shield are utilized to process and display results, respectively. For evaluation purposes, different local products of tap water, bottled drinking water, and home-filter treated water samples were tested using the developed setup. A calibration curve with coefficient of determination (R2) of 0.98 was obtained when absorbance of the prepared standard solutions was measured as a function of the concentrations. In conclusion, this is the first step towards a compact, portable, and reliable system for nitrate detection in water for point-of-care applications

Lab on a Chip for the Colorimetric Determination of Nitrite in Processed Meat Products in the Jordanian Market

Nitrite and Nitrate have been used extensively as additives in various meat products to enhance flavor, color, and to preserve the meat from the bacterial growth. High concentrations of nitrite can threat human health since several studies in the literature claim that nitrite is associated with cancer incidences, leukemia, and brain tumors. Therefore, it is vital to measure the nitrite concentrations in processed meat products. In this study, an in-lab miniaturized photometric detection system is fabricated to inspect the nitrite concentration in processed meat products in Jordan. The analytical performance of nitrite detection is evaluated based on three key statistical parameters; linearity, limit of detection, and limit of quantitation. Respectively, for the fabricated system, the three values are found to be equal to 0.995, 1.24 &times; 10&minus;2 ppm, and 4.12 &times; 10&minus;2 ppm. Adherence to Beer&rsquo;s law is found over the investigated range from 2.63 ppm to 96.0 ppm. The developed system is utilized for photometric detection of nitrite in processed meat products available in the Jordanian market like pastrami, salami, and corned beef. In all of the analyzed samples, the nitrite content is found to be lower than 150 ppm, which represents the maximum allowable nitrite limit

An Electrochemical Sensor for the Detection of Albendazole Using Glassy Carbon Electrode Modified with Platinum-Palladium Nanocomposites

An electroanalytical electrode for the detection of albendazole (ABZ) active ingredient in pharmaceutical dosage form and in contaminated animal-derived products was developed using a glassy carbon electrode modified with platinum-palladium nanoparticles. The electro-catalytic performance of the bimetallic-modified glassy carbon electrode was compared with its bare counterpart. Under optimized conditions, the modified electrode revealed two well-resolved anodic peak currents at 1.10 and 1.23 V using differential pulse voltammetry. Pure ABZ, as well as ABZ in spiked foods (milk and chicken), were detected with little interference from the food matrix. This electrode demonstrated high sensitivity and applicability, with a lower limit of detection of 0.08 µmol L−1 in aqueous solution and 10 µmol L−1 in the contaminated ground chicken and 100 µmol L−1 in the contaminated milk sample. The fabricated sensor is low in cost and appropriate for the estimation of albendazole in tablet dosage forms and biological samples, and so can act as a quality control tool in the pharmaceutical and food industry