Alcohol sensing membranes coated on overhead transparency films for the continuous monitoring of ethanol, propanol and butanol are presented. Alcohol oxidation catalyzed by alcohol oxidase in conjunction with the fluorescence quenching reaction of oxygen-sensitive dye ion-pair, tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) didodecylsulphate was chosen for the determination. Alcohol oxida...

An electroanalytical study for the amperometric determination of ascorbic acid (AA) in a human urine sample at a bare glassy carbon electrode using the CPC (cetylpyridinium chloride) surfactant is described. Under the optimized conditions of E(pa), I(pa), CPC concentration and pH, the oxidation peak potential of the AA shifts towards a less positive potential, and the peak current increase in a...

The application of laser-induced breakdown detection (LIBD) as a new and powerful particle-analyzing technique for the determination of solubility data by monitoring initial colloid generation, when the metal ion concentration just exceeds the solubility at a given pH value, is investigated. Laser-induced breakdown spectroscopy (LIBS) is used for selective analysis of an aqueous suspension of l...

C18 Empore 96-well extraction disc plates have been employed for the analysis of three drugs with different polarities in plasma in conjunction with HPLC-UV, rufinamide, ICL670 and an anticonvulsant agent (AA1) in an early stage of development. With the most polar compound (AA1), ion-pair extraction at pH 12 was applied. The method developed for the assay of AA1 in plasma was applied to its det...

Previous methods for the determination of homogentisic acid have been based upon its ability to reduce silver (I), phosphomolybdic acid (a), or iodine (3-5). The error introduced by other biological substances which have similar reducing properties is inconsequential in the determination of the relatively large amounts of homogentisic acid present in urine from a patient with alcaptonuria. Such...

The hyperthermophilic glycoside hydrolase family endocellulase 12 from the archaeon Pyrococcus furiosus (EGPf; Gene ID PF0854; EC 3.2.1.4) catalyzes the hydrolytic cleavage of the β-1,4-glucosidic linkage in β-glucan in lignocellulose biomass. A crystal of EGPf was previously prepared at pH 9.0 and its structure was determined at an atomic resolution of 1.07 Å. This article reports the crystall...

The electrochemical oxidation of 8-oxoguanine (8-oxoG) in the presence of uric acid (UA) was studied by differential pulse voltammetry over a wide pH range (1-12). The results showed that both compounds follow a pH-dependent oxidation mechanism that involves two electrons and two protons corresponding to reversible charge transfer reactions. The difference between the peak potential for the oxi...

In plants, the extracellular space (apoplast) is one of the main places where exchange of molecules occurs between cells. Not only is this compartment involved in the storage of multiple metabolites and ions, including calcium and protons, but it also plays a role in the transmission of signaling molecules for cell-to-cell communication. It has recently been shown multiple times that these two ...

We describe an improved method for the quantitation of total and direct bilirubin in serum in which sodium dodecyl sulfate is used as an accelerator. Viscous and caustic reagents are not needed, and the effects of protein matrix, hemoglobin interference, and turbidity are minimized. For total bilirubin determination we first add the sodium dodecyl sulfate reagent to serum, then a diazo reagent ...

BACKGROUND Cardiac output (CO) is a major diagnostic and prognostic factor in pre-capillary pulmonary hypertension (PH). Reference methods for CO determination, like thermodilution (TD), require invasive procedures and allow only steady-state measurements. The Modelflow (MF) method is an appealing technique for this purpose as it allows non-invasive and beat-by-beat determination of CO. METHO...