JBCS

Carbon supported ternary PtSnCu (1:1:1) catalysts were synthesized by reduction of the metal precursors in ethanol reflux and characterized by EDX, XRD and TEM analyses. Their activity for ethanol oxidation was compared with that of binary PtSn/C and PtCu/C prepared with the same method. A drastic decrease of the onset potential for ethanol electrochemical reaction on PtSnCu was observed.

Previous studies of Dalbergia frutescens have shown that the chemical composition of the essential oil is strongly influenced by cloudiness, rainfall, ambient temperature, and insolation. The present work demonstrated that the main compounds detected in this essential oil were strongly influenced by seasonality, mainly due to the levels detected of β-ionone and β-damascenone.

This paper describes the microwave-assisted synthesis of ten 3-methoxycarbonyl-γ-butyrolactone derivatives and the evaluation of their in vitro antileishmanial activity against promastigote forms of Leishmania amazonensis.

Two new triterpenes, 3,16-dioxo-29-hydroxyfriedelane and 3-oxo-16β,29-dihydroxyfriedelane were isolated from branches of Maytenus robusta and their powder crystal structures were established. The in vitro cytotoxicity of these compounds and other four triterpenes was evaluated against 4T1 cancer cells.

The effect of Zn on side-chain alkylation of toluene with methanol over KX zeolite was carried out in a fixed-bed flow reactor under atmospheric pressure. The results showed that Zn addition had an excellent promoting effect on the side-chain alkylation of toluene, and the conversion of toluene over Zn-modified KX with a content of 0.8 wt.% was almost double that of KX at 450 ºC.

The production and consumption of honey have increased continuously, however, there is great concern about the contamination of honey by pesticides from crop fields or treatment of hives. Thus, to evaluate this potential risk a method for the determination of pesticide residues in honey by modified QuEChERS and gas chromatography with electron capture detection (GC-ECD) has been developed and validated.

The HZSM-5 catalyst with 0.4 mol L⁻¹ NaOH shows good catalytic performance for ethanol dehydration to ethylene. Both the changes in the acidic properties and in the porous structure contribute to the improvement in the catalytic performance.

A comparative study of different photochemical oxidation processes and a detailed characterization of the by-products of diesel oil degradation were performed using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GCxGC-TOFMS).

Sterols (e.g., cholesterol) and n-alcohols in four dated sediment cores were used to assess the sources of organic matter to a well preserved spot in the SW Brazilian coast.

Glaucomas are a family of "silent diseases". In this work, precise, rapid and extraction-free square-wave adsorptive cathodic stripping voltammetry method has been developed for trace quantitation of anti-glaucoma drug levobunolol HCl in commercial formulation (ophthalmologic drops) and human serum. The method can be recommended for quantification of levobunolol HCl in quality control and clinical laboratories.

In this work, an electrochemical method is proposed using flow injection analysis and amperometric detection with screen-printed carbon electrodes for morpholine determination which is present in commercial corrosion inhibitors.

Glaucomas are a family of "silent diseases". In this work, precise, rapid and extraction-free square-wave adsorptive cathodic stripping voltammetry method has been developed for trace quantitation of anti-glaucoma drug levobunolol HCl in commercial formulation (ophthalmologic drops) and human serum. The method can be recommended for quantification of levobunolol HCl in quality control and clinical laboratories.

A variety of solvent extractors were assessed to determine different classes of pesticides in human milk by solid-phase dispersion and GC/ECD. The multiresidue analytical method proposed combines extraction and clean up in a single step and quantification is performed by standard addition to avoid the matrix effect.

Some parameters of tomato fruit were evaluated during the ripening of fruits. These data were correlated with the observed matrix effect on the analysis of five pesticides in organic extracts obtained in the SLE-PLT by GC-ECD.

New propionyl-spaced biheterocycles 5-[(5-trifluoromethyl-5-hydroxy-4,5-dihydro-1H-pyrazol-1-yl)-1-propan-1-one-3-yl]-2-methyl-7-trifluoromethylpyrazolo[1,5-α]pyrimidines were synthesized by two successive regiospecific cyclocondensations from methyl 7,7,7-trifluoro-4-methoxy-6-oxo-4-heptenoate.

Three new phenolic glycosides, phyllanthuosides A-C, together with twelve known compounds were isolated from the whole plants of Phyllanthus cochinchinensis.

The behaviour of PIC in hydrotropes and alginate was studied by emission spectroscopy. The emission due to J-aggregates (570 nm) increases with the amount of alginate in PIC solutions up to 0.2 g L^-1. At higher alginate concentrations, this emission decreases. Effects are due to the redistribution of the dye over the alginate anionic sites.

The polymer poly(3-hydroxybutyrate) (PHB) and the drug were dissolved in the organic solvent and then emulsified in aqueous solution. To obtain the composite microparticles, we used the microparticles of PHB/ketoprofen (KET), adding them in a solution of 1, 1.5 and 2.0% chitosan (m/v). These were then subjected to spray drying when placed in the spray dryer apparatus. The surface film was modified using glutaraldehyde or genipin as the crosslinking agent.

A method for the quantification of the alkaloids harmane and harmine in sour passion fruit pulp and seeds by dual stir-bar sorptive extraction and high performance liquid chromatography with fluorescence detection (SBSE-LC/Flu) is described.

Under optimized conditions, SDZ was virtually all mineralized and the intermediate compounds were properly identified by GC-MS. An oxidation pathway of the SDZ electrochemical degradation was proposed.

Thiazole esters display smectic A mesophase (SmA) for compounds where the variable connection is derived from (perfluoralkyl)alkyl esters.

Based on essential oil variability, seventeen populations of Marsypianthes (Lamiaceae) may be represented by two chemical sections, one containing M. chamaedrys/M. montana (A) and the other containing M. burchellii (B). M. foliolosa showed greater complexity and occurred in both sections.

Hollow-fiber liquid-phase microextraction of three kinds of synthetic endocrine disrupting compounds in milk, then detected by high-performance liquid chromatography (HPLC).

The presence of pesticides was determined in samples of strawberries using solid-liquid extraction with low-temperature partitioning (SLE/LTP) and gas chromatography-electron capture detection (GC/ECD). Residues of azoxystrobin, difenoconazole, iprodione and chlorothalonil were found.

Spectroelectrochemistry of [Mn^II₂(tidf)(OAc)(ClO₄)(MeOH)] (tidf = a Robson type macrocycle detected the stabilization of mixed-valence Mn₂(II/III) species in solution. Crystallization of [Mn^II₂(tidf)(OAc)(ClO4)(MeOH)] produced an uncommon trimanganese (III/II/III)-complex not observed in solution.