scholarly journals Measurement of 5-aminolaevulinate synthase activity by gas-liquid chromatography with electron-capture detection

1990 ◽  
Vol 270 (1) ◽  
pp. 103-107 ◽  
Author(s):  
A Gorchein
Keyword(s):  
Enzyme Activity ◽  
Liquid Chromatography ◽  
Electron Capture ◽  
Rat Liver ◽  
Ethyl Acetoacetate ◽  
Human Lymphocytes ◽  
Internal Standard ◽  
Electron Capture Detection ◽  
Gas Liquid Chromatography ◽  
Specific Assay

A specific assay for 5-aminolaevulinate synthase activity is described, with a sensitivity comparable with that of radiochemical assays. It is based on measurement by g.l.c. with electron-capture detection of the pentafluorobenzyl ester of the ethyl acetoacetate pyrrole derivative of 5-aminolaevulinic acid, and of the corresponding compound from 6-amino-5-oxohexanoic acid used as internal standard. Enzyme activity has been measured in homogenates of rat liver, spleen, kidney and brain, and in human lymphocytes.

scholarly journals Determination of δ-aminolaevulinic acid in biological fluids by gas-liquid chromatography with electron-capture detection

1984 ◽  
Vol 219 (3) ◽  
pp. 883-889 ◽  
Author(s):  
A Gorchein
Keyword(s):  
Cerebrospinal Fluid ◽  
Liquid Chromatography ◽  
Electron Capture ◽  
Biological Fluids ◽  
Internal Standard ◽  
Electron Capture Detection ◽  
Gas Liquid Chromatography ◽  
Aminolaevulinic Acid ◽  
Highly Sensitive

A derivative of delta-aminolaevulinic acid (AmLev), 2-methyl-3-acetyl-4-(3-propionic acid pentafluorobenzyl ester)pyrrole, with favourable properties for g.l.c. with electron-capture detection, was synthesized. Less than 1 pg could be detected on the column. 6-Amino-5-oxohexanoic acid formed the analogous derivative under similar conditions and was used as the internal standard in the development of a highly sensitive and specific assay for AmLev. The method has been applied to peripheral-venous and umbilical-cord plasma and to cerebrospinal fluid of normal and porphyric subjects.

Measurement of thiamylal and thiopental in plasma by electron capture and flame photometric gas-liquid chromatography.

1977 ◽  
Vol 23 (7) ◽  
pp. 1306-1309 ◽  
Author(s):  
R H Smith ◽  
J A MacDonald ◽  
D S Thompson ◽  
W E Flacke
Keyword(s):  
Liquid Chromatography ◽  
Ethyl Acetate ◽  
Electron Capture ◽  
Internal Standard ◽  
Chromatographic Column ◽  
Gas Liquid Chromatography ◽  
Unchanged Drug ◽  
Chromatographic Procedure ◽  
Isothermal Gas ◽  
Liquid Chromatographic

Abstract We describe an isothermal gas-liquid chromatographic procedure developed for measuring thiamylal and thiopental in plasma. The unchanged drug is extracted into ethyl acetate from acidified plasma, together with an internal standard. The solvent is removed, the residue methylated, aliquots, diluted with benzene, are injected into a 183-cm gas-liquid chromatographic column containing 3% OV-17. Sensitivity of detection is in the nanogram to picogram range.

Liquid and Gas Chromatographic Analysis of Diethyl Phthalate in Water and Sediment

1981 ◽  
Vol 64 (6) ◽  
pp. 1403-1407
Author(s):  
William R Payne ◽  
Jacquelyn E Benner
Keyword(s):  
Liquid Chromatography ◽  
Electron Capture ◽  
High Speed ◽  
High Performance ◽  
Detection System ◽  
Solvent System ◽  
Diethyl Phthalate ◽  
Electron Capture Detection ◽  
Gas Liquid Chromatography ◽  
Water And Sediment

Abstract Diethyl phthalate was determined in water and sediment by high performance liquid chromatography (HPLC) and in water by gas-liquid chromatography with electron capture detection (GLC-ECD). Water samples were extracted with hexane, using a high-speed homogenizer-ultrasonic apparatus and a test tube mixer. Sediments were Soxhlet-extracted using acetonitrile. For HPLC, diethyl phthalate was determined in normal phase mode using a Zorbax-CN column, a 2% isopropanol-hexane solvent system, and a UV variable wavelength detector. For GLC-ECD, a 3% SE-30 Gas-Chrom Q column with a 63Ni electron capture detection system was used. Recoveries from fortified samples ranged from 93.9 to 98.0% for water atO.Ol-0.50 ppm, and from 90.0 to 93.6% for sediment atO.2-2.Oppm.

DETERMINATION OF DEHYDROEPIANDROSTERONE AND DEHYDROEPIANDROSTERONE SULPHATE IN HUMAN PLASMA USING ELECTRON CAPTURE DETECTION OF 4-ANDROSTENE-3,6,17-TRIONE AFTER GAS-LIQUID CHROMATOGRAPHY

1972 ◽  
Vol 53 (3) ◽  
pp. 461-474 ◽  
Author(s):  
F. H. de JONG ◽  
H. J. van der MOLEN
Keyword(s):  
Liquid Chromatography ◽  
Electron Capture ◽  
Plasma Concentrations ◽  
Mean Value ◽  
Electron Capture Detection ◽  
Gas Liquid Chromatography ◽  
Mean Values ◽  
Peripheral Plasma ◽  
Competitive Protein Binding ◽  
The Mean

SUMMARY A method for the measurement of dehydroepiandrosterone (DHA) and of its sulphate (DHAS) in human peripheral plasma is described and evaluated. After isolation of DHA from the sample the steroid is oxidized to 4-androstene-3,6,17-trione, which is measured with an electron capture detector after gas—liquid chromatography. It is possible to detect 100 pg 4-androstene-3,6,17-trione. The smallest amount of DHA per sample that can be distinguished from zero is approximately 4 ng, when recovery (27·9 ± 8·8%) and method blank (0·23 ± 0·38 ng) are taken into account. The oxidation to 4-ene-3,6-diones is specific for steroidal 5-en-3-ols. Specificity for DHA is ensured by several chromatographic steps. Repeated estimation of 10 ng DHA gave a mean value of 9·6 ± 1·45 (s.d.) ng (n = 35). Mean concentrations and their standard deviations for DHA and DHAS in peripheral plasma from 18 individuals were 0·50 ± 0·25 and 78 ± 40 μg/100 ml, respectively, at 08.30 h and 0·32 ± 0·17 and 84 ± 34 μg/100 ml, respectively, at 17.00 h of the same day. Levels of plasma cortisol in the same plasma samples estimated with a competitive protein-binding method were 16·7 ± 1·8 and 11·9 ± 3·8 μg/100 ml, respectively. No significant differences between the sexes were observed by any of the three assays. The mean values of the plasma concentrations of cortisol and DHA in the morning were significantly higher than those in the evening (P < 0·001 and P < 0·005, respectively). In contrast, the mean value of the plasma levels of DHAS in the morning was significantly lower than that in the evening (P < 0·025).

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