BACKGROUND Urinary organic acids are water-soluble intermediates and end products of the metabolism of amino acids, carbohydrates, lipids, and a number of other metabolic processes. In the hereditary diseases known as organic acidurias, an enzyme or co-factor defect in a metabolic pathway leads to the accumulation and increased excretion of one or more of these acidic metabolites. Gas chromatog...

The essential oil composition from the leaves of Strychnos axillaris Colebr. (Loganiaceae) growing in Malaysia was examined for first time. obtained by hydrodistillation and fully characterized gas chromatography (GC-FID) chromatography-mass spectrometry (GC-MS). In total, 15 components were identified oil, which made up 87.2% total oil. is composed mainly ?-ionone (20.2%), ?-ionone (19.5%), bi...

A research area of great interest to the flavour industry is the analysis of odour active compounds in essential oils. In this paper, a methodology is presented for the identification of character-impact odorants in essential oil samples using (a) gas chromatography-olfactometry (GC-O); (b) comprehensive two-dimensional gas chromatography (GC x GC) combined to time-of-flight mass spectrometry (...

Abstract. Nitrous oxide (N2O) is one of the important greenhouse gases. N2O emissions from anthropogenic sources are approximately 7-8 million tones N/yr worldwide and 70% of these emissions are caused by crop and animal production. In this study, direct N2O production from dairy cattle (enteric fermentation) and feces/urine temporarily stored in two freestall dairy barns were measured with 1) ...

the composition of the essential oils of two african (“white” and “yellow”) olibanums available in the commercial market of isfahan (iran) was analyzed by gas chromatography (gc) and gc-mass spectroscopy methods. the main constituents of the “white” olibanum oil were alpha-pinene (34.8%), limonene (15.9%), alphathujene (9.0%), para-cymene (7.0%), myrcene (6.2%) and sabinene (6.0%). major compon...

In this study, cattle manure was converted to bio-oil by subcritical hydrothermal liquefaction in the presence of NaOH. The effects of conversion temperature, process gas, initial conversion pressure, residence time and mass ratio of cattle manure to water on the bio-oil yield were studied. The bio-oil was characterized in terms of elemental composition, higher heating value, ultraviolet-visibl...

Comprehensive Two-Dimensional Gas Chromatography for Detailed Characterisation of Petroleum Products — Comprehensive two-dimensional gas chromatography (GC×GC) is a major advance for the detailed characterisation of petroleum products. This technique is based on two orthogonal dimensions of separation achieved by two chromatographic capillary columns of different chemistries and selectivities. ...

gas chromatography (gc) and gas chromatography mass spectrometry (gc-ms) were employed to determine the chemical composition of essential oil obtained from dry fruits of carum copticum. thymol (36.7%), -terpinene (36.5%) and -cymene (21.1%) were found to be the major constituents of the oil. the anti-bacterial activities of the oil were mainly investigated against food poisoning bacteria (sal...

The zinc-cadmium oxide (ZnO-CdO) nanocomposites with different weight percentages of cadmium oxide (CdO) nanoparticles were successfully synthesized by the sonochemical method using zinc and cadmium nitrates as precursors to probe their nano-structured surfaces for the decomposition reactions of chloroethyl phenyl sulfide (CEPS) as a surrogate of sulfur mustard agent simulant. Scanning electron...

The objective of this research was to study the biological activities of various extracts and the chemical composition of the essential oil Trigonella monantha C. A. Mey. subsp. monantha by gas chromatography (GC) and gas chromatography-mass spectroscopy (GC-MS), from the compounds derived from the aerial parts. The overall results of T. monantha tests allow us to conclude various extracts [hex...