Detection of Anti-Ulcer Drugs and Their Metabolites in Horse Urine by Liquid Chromatography – Mass Spectrometry

This paper describes a convenient method for the extraction and detection of eight anti-ulcer drugs simultaneously in horse urine, a relatively complex and viscous matrix, using a single-step liquid-liquid extraction followed by high-performance liquid chromatography – mass spectrometry (LC-MS). Anti-ulcer drugs were isolated from horse urine by salting out and liquid-liquid extraction. Detection of these drugs at concentrations below 1 ng mL^?1 could be achieved using LC-MS-MS in the positive atmospheric pressure chemical ionisation (APCI) mode. The above analysis was also extended to elimination studies of horses administered with ranitidine and omeprazole. The urinary elimination data of these two drugs suggest that ranitidine was eliminated from horse urine at a much slower rate than omeprazole. In addition, three ranitidine metabolites and six omeprazole metabolites were identified for the first time in equine urine samples.     

Miscibility in systems containing aqueous solutions of various alkylbenzenesulfonates, toluene and, n-butanol

Miscibility relationships in four-component systems containing sodium alkylbenzenesulfonates, toluene, n-butanol, and water were studied at 25°C in the hope of clarifying the complex systems used in the “micellar flood” enhanced oil recovery process. Phase boundary curves for the pseudo three-component systems (constant sulfonate/water ratios, 2.5 moles sulfonate per kg water) were determined. The sulfonates included those of benzene, toluene, xylene, ethylbenzene, isopropylbenzene, mesitylene, cymene, methyl-t-butylbenzene, and diisopropylbenzene, in all of which the alkyl substituents are smaller than in the usual surfactants. The phase boundary curves have similar and fairly symmetrical shapes. The amount of n-butanol (cosolvent) required to produce miscibility decreases with increasing number of alkyl carbons on the benzene ring of the sulfonates and seems relatively independent of the isomeric structure. The sodium salt of diisopropylbenzenesulfonate gives the lowest phase boundary curve (least n-butanol required for miscibility) among the nine sulfonates studied.     

The basis set superposition error in multilevel methods: a test on the H2O and HF dimer

The basis set superposition error (BSSE) is often very important in the accurate calculation of dimerization energies. Accurate prediction of thermochemical properties requires appropriate consideration of the basis set incompleteness error. Multilevel methods introduce adjustable parameters to reproduce experimental data, that is, the higher level correction (HLC) in G3 and adjustable coefficients in the MCCM. However, the HLC term is cancelled out and the adjustable coefficients in the MCCM do not remove the BSSE completely. We have calculated the BSSE involved in the multilevel methods. The H₂O and HF dimer systems were used as a test case. This study shows that empirical coefficients do reduce the BSSE in some cases and an MCCM with good parameters can be used to reproduce dimerization energies within chemical accuracy without the BSSE correction.     

SMSI effect on ceria supported Cu-Pd catalysts in the hydrogenation of 1,3-butadiene

Ceria-supported copper-palladium catalysts have been tested in the hydrogenation of 1,3-butadiene. The SMSI behavior of the bimetallic catalysts depended on the temperature of reduction. They were analyzed by H₂ chemisorption and XPS.     

Enhanced electrodeposition of indium hexacyanoferrate thin films through improved plating solution stability

An ordinary plating solution for indium hexacyanoferrate (InHCF) thin film deposition, mainly composed of equal concentrations of In³⁺ and [Fe(CN)₆]^3–, usually forms precipitates rapidly when either concentration is higher than few millimolar. This contributes to the plating solution's instability. Moreover, electrodeposited capacities are limited accordingly. In this work, the plating solution's stability and the electrodeposition of InHCF were greatly enhanced by adding a large amount of K⁺ and/or H⁺. It was found that a 10-mM plating solution added with 1 M HCl and 1 M KCl could be stored as fresh over a one-week period, whereas an unmodified plating solution became useless within a couple of minutes. Also, such cationic additions, especially adding H⁺, increased the electrodeposited capacity ca. 18 times at least, as compared with that obtained from the unmodified plating solution. Furthermore, related enhancing mechanisms were proposed and verified. To sum up, this study offers a means for better InHCF electrodeposition and should promote the applications of InHCF films. Electronic Publication     

Substituted γ-lactones. Some observations on the synthesis and reactivity of 4-aroyl-3-hydroxy-2(5H)-furanones

The reaction pathway towards formation of 4-aroyl-3-hydroxy-2(5H)-furanones 1 from the base catalyzed reaction between an acetophenone, diethyl oxalate and formaldehyde was investigated. If methoxide was used as base, a transesterification was found to occur in the first step, while a side reaction, namely the retro Claisen reaction, was in competition with the desired lactone formation in the second step. The nature of the solvent and the acidic character of 1 as well as the basicity of the aminoarylene were found to have a profound influence on the course of the reaction of 1 with aminoarylenes.     

A simple and general method for the synthesis of multicomponent Na2V6O16.3H2O single-crystal nanobelts

Multicomponent Na2V6O16.3H2O (barnesite) single-crystalline nanobelts were synthesized by a direct reaction-crystallization growth of bulk V2O5 and NaF powders under hydrothermal treatment without using any templates or catalysts. This new strategy could be extended to prepare other one-dimensional multicomponent nanomaterials including ammonium, alkali-metal or alkali-earth metal vanadium oxide bronzes and other transition metal oxyfluorides. This is an efficient and mild solution method with clear advantages over the traditional high-temperature approach for the large-scale production of 1D multicomponent nanomaterials. The applicability of this approach toward the preparation of other inorganic systems, such as tungstates and molybdates, will be explored.