scholarly journals Methyl mercaptan and dimethyl disulfide production from methionine by Proteus species detected by head-space gas-liquid chromatography

1977 ◽  
Vol 6 (3) ◽  
pp. 187-194
Author(s):  
N J Hayward ◽  
T H Jeavons ◽  
A J Nicholson ◽  
A G Thornton
Keyword(s):  
Liquid Chromatography ◽  
Dimethyl Disulfide ◽  
Defined Medium ◽  
Automated Detection ◽  
Gas Liquid Chromatography ◽  
Methyl Mercaptan ◽  
Proteus Vulgaris ◽  
Head Space ◽  
Disulfide Production

Head-space gas-liquid chromatography and mass spectrometry were used to detect and identify products formed by Proteus vulgaris, P. mirabilis, P. morganii, and P. rettgeri from a defined medium supplemented with either phenylalanine, methionine, valine, leucine, histidine, lysine, ornithine, threonine, asparagine, aspartic acid, or tryptophan. In a detailed study of the products formed by 68 strains of Proteus spp. from L-methionine, the production of large amounts of both dimethyl disulfide and methyl mercaptan was found to be a characteristic of the genus. Both sulfur products appeared within a few hours of inoculation. Dimethyl disulfide was a more sensitive indicator of growth than the spectrometric determination of optical density. This suggests that it could be useful for the rapid, automated detection of any species of Proteus.

Gas Chromatographic Determination of Residual Hexane in Modified Hop Extract

1972 ◽  
Vol 55 (6) ◽  
pp. 1226-1227
Author(s):  
Mark A Litchman ◽  
Lewis A Turano ◽  
Ronald P Upton
Keyword(s):  
Liquid Chromatography ◽  
Quantitative Determination ◽  
Chromatographic Determination ◽  
Methanol Solution ◽  
Chromatographic Column ◽  
Gas Liquid Chromatography ◽  
Porapak Q ◽  
Residual Hexane ◽  
Head Space

Abstract A method is described for the quantitative determination of hexane in modified hop extract by head-space gas-liquid chromatography. A sample of extract is weighed into a serum vial and water-methanol solution is added. The vial is sealed tightly and heated 1 hr in a 70°C bath. A sample of the head-space gas over the solution is injected onto a Porapak Q gas chromatographic column for determination. Recovery of 2–29 ppm hexane added to potassium isohumulone was 95.5–114.8%. The method may be applicable to other hop extracts.

scholarly journals Assessment of technique for rapid detection of Escherichia coli and Proteus species in urine by head-space gas-liquid chromatography

1977 ◽  
Vol 6 (3) ◽  
pp. 202-208 ◽  
Author(s):  
N J Hayward ◽  
T H Jeavons
Keyword(s):  
Escherichia Coli ◽  
Liquid Chromatography ◽  
Dimethyl Disulfide ◽  
Gas Liquid Chromatography ◽  
Early Exponential Phase ◽  
E Coli ◽  
Head Space ◽  
Microbiological Examination ◽  
Tract Infections ◽  
Further Development

A test depending on the production of ethanol by Escherichia coli from lactose and dimethyl disulfide by Proteus spp. from methionine in the early exponential phase of growth and the detection of these products by head-space gas-liquid chromatography has been applied to 75 specimens of urine selected to provide the most stringent trial of the test. The test was found to be rapid and reliable for the commonest findings in the microbiological examination of urine. In 3 to 4 h it detected "significant" numbers (greater than 10(5)/ml) of E. coli or of Proteus mirabilis or P. inconstans A, identified as Proteus spp., in 23 urines. It recorded the absence of infection from 32 urines containing borderline or "not significant" numbers of any organism. Significant numbers of other organisms in 13 urines were not mistaken for E. coli or Proteus spp. However, the test was less successful for some less common findings. Klebsiella ozenae in significant numbers in one urine was mistaken for E. coli. P. morganii in significant numbers in one urine was not detected. E. coli or P. mirabilis mixed with significant numbers of another organism were not detected in four out of five urines. The technique is simple and could be automated. It appears to merit more extensive trial in a hospital laboratory and further development to detect and correctly identify more species that cause urinary tract infections.

GASCHROMATOGRAPHIC DETERMINATION OF STEROIDS IN THE URINE OF PATIENTS WITH CUSHING'S SYNDROME

1971 ◽  
Vol 67 (2) ◽  
pp. 303-315 ◽  
Author(s):  
A. J. Moolenaar ◽  
A. P. van Seters
Keyword(s):  
Liquid Chromatography ◽  
Cushing’S Syndrome ◽  
Normal Subjects ◽  
Diagnostic Value ◽  
Cushing's Syndrome ◽  
Gas Liquid Chromatography ◽  
Obese Subjects

ABSTRACT The 17-oxosteroids were estimated in the urine of 27 patients with Cushing's syndrome by gas-liquid chromatography (G. L. C.). The values of the various steroid fractions are compared with those of normal subjects, patients with thyrotoxicosis and obese subjects. The effect of the age of the patients on the diagnostic value of the invidual 17-oxosteroids and their ratios is discussed.

Simultaneous Determination of Lactulose and Mannitol in Urine of Burn Patients by Gas-Liquid Chromatography

1992 ◽  
Author(s):  
Ronald L. Shippee ◽  
Avery A. Johnson ◽  
William G. Cioffi ◽  
James Lasko ◽  
Thomas E. LeVoyer
Keyword(s):  
Liquid Chromatography ◽  
Simultaneous Determination ◽  
Gas Liquid Chromatography ◽  
Burn Patients

scholarly journals Gas Chromatographic Determination of Traces of Accelerants in Physical Evidence

1972 ◽  
Vol 55 (4) ◽  
pp. 840-845 ◽  
Author(s):  
Charles R Midkiff ◽  
Willard D Washington
Keyword(s):  
Liquid Chromatography ◽  
Solvent Extraction ◽  
Vapor Phase ◽  
Selection Criteria ◽  
Chromatographic Determination ◽  
Operating Parameters ◽  
Gas Liquid Chromatography ◽  
Internal Standards ◽  
Physical Evidence

Techniques developed for use with gas-liquid chromatography for the examination of evidence collected at the scene of suspected arson fires and firebombings are discussed. Both solvent extraction and vapor phase examinations are employed. Internal standards are used for the identification of specific components in actual samples to allow confirmation of hydrocarbon type, e.g., gasoline and kerosene. Operating parameters and solvent selection criteria are included. Results obtained from known materials and residual hydrocarbons in actual samples are compared.

Micro-Determination of p-Hydroxybenzoic Esters in Pharmaceuticals and Cosmetics

1977 ◽  
Vol 60 (1) ◽  
pp. 56-59 ◽  
Author(s):  
Emil Weisenberg ◽  
Baruch Gershon ◽  
Judith Schoenberg
Keyword(s):  
Liquid Chromatography ◽  
Phosphate Ester ◽  
Specific Method ◽  
Gas Liquid Chromatography ◽  
Direct Extraction ◽  
Flame Photometric Detector ◽  
Phenol Derivatives ◽  
Margin Of Error ◽  
Diethyl Phosphate

Abstract A rapid and specific method is described for the determination of microamounts of methyl, propyl, and butyl p-hydroxybenzoic esters (parabens) in pharmaceuticals and cosmetics. The method involves the direct extraction of parabens into benzene or chloroform followed by derivatization with phosphorochloridate. The diethyl phosphate ester derivatives are cleaned up on a Florisil minicolumn and finally measured by gas-liquid chromatography on 5% OV-210 on Gas-Chrom Q. A flame photometric detector or a KCl thermionic detector may be used. The concentration response was linear up to 40 ng parabens. The reproducibility and margin of error were tested with fortified samples. This method may be applied to the estimation of other phenol derivatives.

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