Capillary Gas Chromatographic Analysis of Volatile and Non-Volatile Organic Acids from Biological Samples as the t-Butyldimethylsilyl Derivatives

Schooley, D.L.; Kubiak, F.M.; Evans, James V.

doi:10.1093/chromsci/23.9.385

Cited by 61 publications

(28 citation statements)

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“…Enzyme activities were also expressed as nmol substrate metabolized/(min⅐g wet feces). Fecal dry weight was determined by oven drying at 105°C for 17 h. Fecal SCFA were measured by the method of Schooley et al (1985). Samples of the homogenized fecal samples (1 g) were suspended in 9 g/L NaCl, spiked with 500 L internal standard (heptanoic acid, final concentration 1 mmol/L), and extracted twice with 2.5 mL diethyl ether.…”

Section: Methodsmentioning

confidence: 99%

Rye Bread Improves Bowel Function and Decreases the Concentrations of Some Compounds That Are Putative Colon Cancer Risk Markers in Middle-Aged Women and Men

Gråsten

Juntunen

Poutanen

et al. 2000

The Journal of Nutrition

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Cereal fiber may reduce the risk of colorectal cancer by diluting colonic contents due to increased fecal output, by accelerating intestinal transit, by increasing fecal frequency and by altering bacterial metabolism. The effects of whole-meal rye bread on some putative colon cancer risk markers were investigated in 17 healthy Finnish subjects using a randomized crossover trial with two 4-wk bread consumption periods and a 4-wk washout period between the bread periods. White wheat bread was used as a control. Test breads covered a minimum of 20% of the daily energy intake (range, 4330 -14,033 kJ/d). Intestinal transit time, stool weight, fecal bacterial enzyme activities and short-chain fatty acid, ammonia, diacylglycerol (DAG) and bile acid concentrations in feces (expressed per gram wet feces) were measured. Whole-meal rye bread significantly increased fecal output and fecal frequency and shortened mean intestinal transit time compared with wheat bread in both women and men. Activities of ␤-glucuronidase and ␤-glucosidase (expressed per gram wet feces) were significantly lower in men and urease activity significantly higher in women during the rye bread period (RBP). Fecal butyrate concentration was higher during the RBP in men. Fecal ammonia and DAG concentrations did not differ between bread periods. Fecal total and secondary bile acid concentrations were significantly lower during RBP in both women and men. This study shows that whole-meal rye bread significantly improves bowel function in healthy adults and may decrease the concentration of some compounds that are putative colon cancer risk markers.

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Section: Methodsmentioning

confidence: 99%

Rye Bread Improves Bowel Function and Decreases the Concentrations of Some Compounds That Are Putative Colon Cancer Risk Markers in Middle-Aged Women and Men

Gråsten

Juntunen

Poutanen

et al. 2000

The Journal of Nutrition

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“…With limited availability of isotope-labelled NDC, isotope dilution is one technique with which to measure exogenous VFA production. VFAs in biological fluids have been measured by a number of techniques, including enzymatic methods, [17][18][19] gas chromatography, 20,21 and liquid chromatography. 22,23 Before analysing VFAs from biological fluids, sample clean-up and deproteinisation are necessary.…”

mentioning

confidence: 99%

“…The tert-butyldimethylsilyl (tBDMS) derivatives of VFAs have been successfully used in a number of isotope dilution studies because they produce characteristic high-mass ions for each VFA that can be used for quantitation. 13,20,21,27 The ubiquitous nature of VFAs, especially acetate, has often hampered their analysis and correcting for this background is a problem for the analyst when measuring isotope ratios. 28 Gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) is a technique whereby complex mixtures are separated by GC prior to combustion of all eluting molecules to CO 2 (H 2 O is also formed).…”

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confidence: 99%

A streamlined approach to the analysis of volatile fatty acids and its application to the measurement of whole‐body flux

Morrison

Cooper

Waldron

et al. 2004

Rapid Comm Mass Spectrometry

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Volatile fatty acids (VFAs) are produced in the human colon by the bacterial breakdown of carbohydrates that escape digestion and absorption in the small intestine. They have important local and systemic effects on gastrointestinal and nutritional functions. Measuring their production is difficult because of inaccessibility of sampling sites and low circulating concentrations. Stable isotope tracer techniques are a way to measure VFA production but require measurement of isotope dilution in blood and other biological fluids. We have developed a streamlined and robust method to measure the concentration and enrichment of [(2)H]-labelled VFAs by gas chromatography/mass spectrometry (GC/MS) and [(13)C]-labelled VFAs by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Both types of analysis were carried out on the same samples allowing multiple tracer studies to be conducted. Good accuracy and repeatability were found for GC/MS analysis of [(2)H]-labelled VFAs. Careful handling of the background contribution, especially acetate, allowed quantitation of concentration and enrichment within the analysis. GC/C/IRMS analysis of [(13)C] VFAs was also achieved with good accuracy and repeatability. This methodology was used to determine whole-body acetate production in two subjects using multiple tracers ([(2)H(3)]- and [1-(13)C]acetate) and blood and urine sampling. Whole-body acetate flux was similar when measured either with [(2)H(3)]- or [1-(13)C]acetate, and when flux was determined from plasma or urine tracer enrichment. This new method will permit rapid and accurate measurement of VFA flux using [(2)H]- and/or [(13)C]-labelled VFAs as tracers. Measurements of the contribution of colonic VFA production to whole-body VFA flux are now possible.

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“…The organic acids in the leachate water used in the experiment were alkaline extracted by adding 0.1 M NaOH (Merck) to the samples. Concentrated HCl (pro analysis, Merck) was then added to the water phase and undissociated acids were then extracted with diethyl ether (>98%, Merck) and further derivatized by t-butyldimethylsilyl (>99% Sigma Aldrich, St. Louis, USA) and measured on a gas chromatograph-mass spectrometer (GC-MS) with electron impact ionization (EI) after a method described by Schooley et al [33].…”

Section: Chemical Analysismentioning

confidence: 99%

Aerobic treatment of selective serotonin reuptake inhibitors in landfill leachate

2015

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Background: Pharmaceuticals used in human medical care are not completely eliminated in the human body and can enter the municipal sewage sludge system and leachate water from landfill both as the parent compound and as their biologically active metabolites. The selective serotonin reuptake inhibitors (SSRIs) have a large potential for unwanted effects on nontarget organisms in the environment. Leachates from active or old closed landfills are often treated with continuous stirring and simple aeration in a pond/lagoon before infiltration into the environment. The aim of this work was to simulate the reduction of five SSRIs (citalopram, fluoxetine, paroxetine, sertraline and fluvoxamine) and three of their metabolites (desmethylcitalopram, didesmethylcitalopram and norfluoxetine) during aerobic treatment of leachate from landfills. This landfill leachate-simulation experiment was performed to see what happens with the pharmaceuticals during aerated treatment and continuous stirring of landfill leachate for 120 h. It is important to establish whether different pollutants such as pharmaceuticals can be removed (oxidized or otherwise degraded) or not before infiltration into the environment.

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Capillary Gas Chromatographic Analysis of Volatile and Non-Volatile Organic Acids from Biological Samples as the t-Butyldimethylsilyl Derivatives

Cited by 61 publications

References 0 publications

Rye Bread Improves Bowel Function and Decreases the Concentrations of Some Compounds That Are Putative Colon Cancer Risk Markers in Middle-Aged Women and Men

Rye Bread Improves Bowel Function and Decreases the Concentrations of Some Compounds That Are Putative Colon Cancer Risk Markers in Middle-Aged Women and Men

A streamlined approach to the analysis of volatile fatty acids and its application to the measurement of whole‐body flux

Aerobic treatment of selective serotonin reuptake inhibitors in landfill leachate

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