Search results for "Gas Chromatography"

Capillary column gas chromatographic identification of sugars in honey as trimethylsilyl derivatives.

1987

A method for identifying carbohydrates (mono-, di- and trisaccharides) in honey is presented. It is based on the separate preparation of both trimethylsilyl ethers and oxime trimethylsilyl ethers of the sugars followed by their gas chromatographic separation on a fused-silica capillary column coated with OV-101 using temperature programming. From the two chromatograms, the number of peaks given by each derivatized sugar, their relative retention times and peak-area ratios are used for identification. The identities of two unidentified trisaccharide peaks are considered. Quantitative applications to honey sugar analysis are discussed.

Determination of selected polyaromatic hydrocarbons by gas chromatography–mass spectrometry for the analysis of wood to establish the cause of sinkin…

2014

Abstract The aim of this paper was to establish the cause of sinking of an old wooden vessel by polycyclic aromatic hydrocarbon (PAH) analyses because wood combustion is a source of PAHs. In particular, the molecular PAH patterns generated by each source are like fingerprints and it is possible to determine the processes that generate PAHs by studying their distribution in wood samples. The relative abundance of high molecular weight PAHs, together with the PAH compound ratios and with total index (proposed by us) has demonstrated that samples owe their PAHs in wood archaeological material to a predominant single mode of origin, i.e. combustion processes, therefore we can say that the sinki…

Analysis of resveratrol in Burgundy wines

1993

Recent studies have shown that resveratrol (3,5,4'‐trihydroxystilbene), a phytoalexin related to grape disease resistance, could occur in American and Bordeaux wines. It was also suggested that resveratrol might have cardioprotective activities in humans, as a result of drinking wine. We report here the presence of this compound in Burgundy wines. Analysis of resveratrol in wine was carried out using gas chromatography and gas chromatography—mass spectrometry.

Carbohydrates from Chemical Pulps: Characterization by Capillary Zone Electrophoresis

2006

Capillary zone electrophoresis (CZE) is one of the novel separation techniques, being applicable, for example, to virtually all important biomass-derived monosaccharides. However, in spite of this fact the utilization of this technique in the pulp and paper industry is currently rather limited. In this chapter practical guidance and some application examples are given to show how carbohydrate material (polysaccharides, oligosaccharides, and neutral and acidic monosaccharides) in pulps and spent liquors can be analyzed by CZE. Emphasis is placed on sample preparation and separation conditions including comparison with other separation methods, such as gas chromatography (GC) and high-perform…

Trifluoracetylierung von aminosäureestern und dipeptidestern mit N-trifluoracetyl-polyamid 66.

1981

N-Trifluoroacetyl-Polyamid 66 (1) is used for the trifluoroacetylation of amino acid- and dipeptide esters. Advantages and limitations of the polymeric reagent compared with low molecular trifluoroacetylating reagents are discussed. A mixture of amino acid methyl esters can be converted by 1 to the N-trifluoroacetyl derivatives, which are separated and identified by gas chromatography.

Distribution of volatile organic compounds in Sicilian groundwaters analysed by head space-solid phase micro extraction coupled with gas chromatograp…

2008

This work presents the results of an assessment of the existence and concentration of 13 volatile organic compounds (VOCs) in groundwaters from 14 hydrological basins in Sicily (25,710km (2)). On the basis of hydrological, hydrogeochemical and geological studies, 324 sampling points were selected. All groundwater sampled were collected twice, from October to December 2004 and from February to May 2005, and were analysed to determine the concentration and spatial distribution of the VOCs in the aquifers. The need to analyze a large number of samples in a short space of time so as to obtain quantitative analyses in trace concentration levels spurred us to create a new analytical method, both …

Polyunsaturated fatty acids and Plasmalogens in diabetics

2012

Purpose Plasmalogens (PLS) are phospholipids characterized by a vinyl ether bond and a preferential esterification of polyunsaturated fatty acids (PUFA). We have previously shown that the lack of PLS leads to retinal hyper-capillarization. We hypothesize that PLS are negative regulators of vascular development, and aimed to check their circulating levels in diabetic patients. Methods Blood samples were collected from 88 patients and 14 control subjects. Among diabetics we had 14 patients without diabetic retinopathy (DR), 12 with a mild non proliferative DR, 12 with a moderate non proliferative DR, 22 with a severe non proliferative DR and 24 with a proliferative DR (PDR). Erythrocytes were…

Der acidolytische abbau von polyoxymethylenen. 18. Mitt. über polyoxymethylene

1962

Beim acidolytischen Abbau von Polyoxymethylendihydraten wurden gaschromatographisch folgende Substanzen identifiziert: Formaldehyd, Wasser, Methanol, Ameisensauremethylester sowie Tri- und Tetraoxymethylen. Die Ausbeute an cyclischen Oligomeren und das Verhaltnis Trioxan/Tetraoxymethylen hangen von der Saure, der Saurekonzentration und der Reaktionszeit ab. Es wird ein Abbaumechanismus vorgeschlagen und diskutiert. In the acidic degradation of polyoxymethylenes the following substances are obtained and identified by gas chromatography: formaldehyde, water, methanol, methyl formate, and also tri- and tetraoxymethylene. The yields of the cyclic oligomers and the ratio trioxane/tetraoxymethyle…

Detecting residues of urea and carbamate pesticides

2004

Gas chromatographic study of acetyl derivates of chlorinated guaiacols

1982

The gas chromatography of acetyl derivatives of guaiacol and all chlorinated guaiacols has been studied on SE-30, OV-351 and Carbowax 20M capillary columns. The retention order and relative retention times under isotermal and temperature-programmed conditions are discussed. Different retention times for all mono- and dichloro compounds have been observed on the SE-30 column. However, all trichloroguaiacol isomers were separated only on polar columns. The best overall temperature-programmed separations have been achieved on an SE-30 capillary column.