A volatolomic approach using cerumen as biofluid to diagnose bovine intoxication by Stryphnodendron rotundifolium

An innovative volatolomic approach employs the detection of biomarkers present in cerumen (earwax) to identify cattle intoxication by Stryphnodendron rotundifolium Mart., Fabaceae (popularly known as barbatimão). S. rotundifolium is a poisonous plant with the toxic compound undefined and widely distributed throughout the Brazilian territory. Cerumen samples from cattle of two local Brazilian breeds (‘Curraleiro Pé-Duro’ and ‘Pantaneiro’) were collected during an experimental intoxication protocol and analyzed using headspace (HS)/GC–MS followed by multivariate analysis (genetic algorithm for a partial least squares, cluster analysis, and classification and regression trees). A total of 106 volatile organic metabolites were identified in the cerumen samples of bovines. The intoxication by S. rotundifolium influenced the cerumen volatolomic profile of the bovines throughout the intoxication protocol. In this way, it was possible to detect biomarkers for cattle intoxication. Among the biomarkers, 2-octyldecanol and 9-tetradecen-1-ol were able to discriminate all samples between intoxicated and nonintoxicated bovines. The cattle intoxication diagnosis by S. rotundifolium was accomplished by applying the cerumen analysis using HS/GC–MS, in an easy, accurate, and noninvasive way. Thus, the proposed bioanalytical chromatography protocol is a useful tool in veterinary applications to determine this kind of intoxication.     

Identification of metabolic markers in patients with type 2 Diabetes by Ultrafast gas chromatography coupled to electronic nose. A pilot study

Metabolomics is a potential tool for the discovery of new biomarkers in the early diagnosis of diseases. An ultra-fast gas chromatography system equipped to an electronic nose detector (FGC eNose) was used to identify the metabolomic profile of Volatile Organic Compounds (VOCs) in type 2 diabetes (T2D) urine from Mexican population. A cross-sectional, comparative, and clinical study with translational approach was performed. We recruited twenty T2D patients and twenty-one healthy subjects. Urine samples were taken and analyzed by FGC eNose. Eighty-eight compounds were identified through Kovats's indexes. A natural variation of 30% between the metabolites, expressed by study groups, was observed in Principal Component 1 and 2 with a significant difference (p < 0.001). The model, performed through a Canonical Analysis of Principal coordinated (CAP), allowed a correct classification of 84.6% between healthy and T2D patients, with a 15.4% error. The metabolites 2-propenal, 2-propanol, butane- 2,3-dione and 2-methylpropanal, were increased in patients with T2D, and they were strongly correlated with discrimination between clinically healthy people and T2D patients. This study identified metabolites in urine through FGC eNose that can be used as biomarkers in the identification of T2D patients. However, more studies are needed for its implementation in clinical practice.     

A model for crack formation during active solid pyrolysis of a char-forming solid: crack patterns; surface area generation; volatile mass efflux

A model is developed for the formation and propagation of cracks in a material sample that is heated at its top surface, pyrolyses, and then thermally degrades to form char. In this work the sample is heated uniformly over its entire top surface by a hypothetical flame (a heat source). The pyrolysis mechanism is described by a one-step overall reaction that is dependent nonlinearly on the temperature (Arrhenius form). Stresses develop in response to the thermal degradation of the material by means of a shrinkage strain caused by local mass loss during pyrolysis. When the principal stress exceeds a prescribed threshold value, the material forms a local crack. Cracks are found to generally originate at the surface in response to heating, but occasionally they form in the bulk, away from ever-changing material boundaries. The resulting cracks evolve and form patterns whose characteristics are described. Quantities examined in detail are: the crack spacing in the pyrolysis zone; the crack length evolution; the formation and nature of crack loops which are defined as individual cracks that have joined to form loops that are disconnected from the remaining material; the formation of enhanced pyrolysis area; and the impact of all of the former quantities on mass flux. It is determined that the mass flux from the sample can be greatly enhanced over its nominal (non-cracking) counterpart. The mass efflux profile qualitatively resembles those observed in Cone Calorimeter tests.     

The analysis of volatile trace compounds in landfill gases,compost heaps and forest air

Landfill gas, cryotrapped on a loop fashioned from a length of a capillary gas chromatography (GC) column, was examined for volatile organometallic compounds (VOMCs) and for volatile organic compounds (VOCs) by using GC–mass spectrometry (MS). A large number of organic components were present and many were identified, but the only VOMCs present in high enough concentrations to be detected were trimethylstibine and tetramethyltin. The use of inductively coupled plasma (ICP)‐MS as an element‐specific detector allowed the identification of a number of other organometallic species in the landfill gas, including trimethylarsine and trimethylbismuth, and, for the first time, butyltrimethyltin and dibutyldimethyltin. The presence of molybdenum hexacarbonyl was confirmed. Gas from a large‐scale compost heap and from compost incubated in the laboratory contained iodomethane but no common VOMCs (GC–ICP‐MS). Only VOCs were present in forest air (GC–MS). Copyright © 2003 John Wiley & Sons, Ltd.     

中药微量挥发成分的联机分析：藿香头香成分分析

本文设计了直接蒸馏-顶空分析-预柱低温富集-毛细管色谱-质谱联机分析技术,有效地提取、浓缩、分离和鉴定了藿香的香气成分。实现了天然产物微量多组分的联机快速分析。并首次在霍香的头香成分中发现了乙酸甲酯、3-甲基丁酮、3-甲基-3-丁烯酮等一系列分子量小、易挥发的成分。     

Determination of colloidally-associated polycyclic aromatic hydrocarbons (PAHs) in fresh water using C18 solid phase extraction disks

A new application of reversed-phase octadecyl (C₁₈) solid phase extraction disks has been developed to separate the colloidally-associated polycyclic aromatic hydrocarbons (PAHs) from those that were truly dissolved in the samples of fresh water. A correction for the retention of small amounts of colloidal material on the C₁₈ disks was required, which would have otherwise lead to minor underestimates in the degree of partitioning between the two phases. Using the humic substance Aldrich Humic Acid (AHA) as a model colloid and the 16 PAHs on the US Enrivonmental Protection Agency priority pollutant list, the partitioning coefficients of the PAHs between the colloidal and truly dissolved phases were shown to be proportional to the hydrophobicity of the PAHs, as measured by their octanol water partition coefficients (K_ow). The values for the partition coefficients obtained (cK_doc′) were similar to those previously reported in the literature using alternative methods, confirming that the technique was producing acceptable results. The technique allows the in situ partitioning of PAHs between the truly dissolved and colloidal phases in fresh water bodies to be determined. It will provide an invaluable cross-check of the laboratory-based methods which often require substantial manipulation of the sample and potentially alter the partitioning between the phases.     

Quantum-Chemical Evaluation of the Protolytic Properties of Thiophenols

The enthalpies and free energies of proton affinity (PA) were calculated by the PM3 method for 27 thiophenoxide anions. For thiophenols, linear correlation has been found between the PAs and the values of pK _a measured by different authors in aqueous acetone, aqueous ethanol, and methanol media. The dependences found permit one to predict a priori the protolytic properties of thiophenols. The differential effects of aqueous ethanol media with different ethanol contents on thiophenol acidity were evaluated based on quantum-chemical data.Original Russian Text Copyright © 2004 by A. N. Pankratov and A. V. Shalabai__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 800–806, September–October, 2004.     

The effect of ionizing radiation on microbiological decontamination of medical herbs and biologically active compounds

Several thousand tons of medical herbs are produced annually by pharmaceutical industry in Poland. This product should be of highest quality and microbial purity. Recently, chemical methods of decontamination are recognized as less safe, thus irradiation technique was chosen to replace them in use. In the Institute of Nuclear Chemistry and Technology the national program on the application of irradiation to the decontamination of medical herbs is in progress now. The purpose of the program is to elaborate, on the basis of research work, the facility standards and technological instructions indispensable for the practice of radiation technology.     

Preconcentration of poorly volatile impurities in thin-layer chromatography by thermodesorption of a volatile matrix

A method for preconcentration of poorly volatile impurities by continuous thermodesorption of the major component on a TLC plate is proposed. The method provides multiple (200–500) concentration of the organic impurities present in the initial solution. A simple device for such concentration is suggested. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2075–2076, October, 1998.     

反相高效液相色谱二极管阵列检测器对戊四硝酯粉质量的研究

建立了戊四硝酯粉含量及有关物质的RP-HPLC测定法。采用ODS色谱柱,甲醇/水(70∶30)为流动相,使戊四硝酯与有关物质基线分离,二极管阵列检测器检测波长206nm。本方法操作简便,重现性好。