scholarly journals Analysis of DL-Amino Acid Ratios in Eggshells Using Reverse Phase-High Pressure Liquid Chromatography

2019 ◽  
Author(s):  
Gergana Milkova
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Amino Acid ◽  
High Pressure Liquid Chromatography ◽  
Reverse Phase

scholarly journals A tryptophan C-methyltransferase involved in streptonigrin biosynthesis in Streptomyces flocculus

1984 ◽  
Vol 220 (1) ◽  
pp. 309-313 ◽  
Author(s):  
D L Hartley ◽  
M K Speedie
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Amino Acid ◽  
Stationary Phase ◽  
High Pressure Liquid Chromatography ◽  
Absolute Configuration ◽  
Specific Activity ◽  
Shake Culture ◽  
Methyl Group ◽  
The Absolute

A C-methyltransferase that catalyses the transfer of a methyl group from S-adenosylmethionine to C-3 of tryptophan, resulting in beta-methyltryptophan, has been identified in cell-free extracts of streptonigrin-producing Streptomyces flocculus. The absolute configuration of the product was shown to be (2S,3R)-beta-methyltryptophan by high-pressure liquid chromatography and reactivity with D- and L-amino acid oxidases. In shake culture, maximum specific activity occurs after S. flocculus enters stationary phase, but before significant streptonigrin accumulates.

Quantitation of the Contaminants in Technical Fenitrothion by Reverse Phase High Pressure Liquid Chromatography

1979 ◽  
Vol 62 (6) ◽  
pp. 1222-1230
Author(s):  
William P Cochrane ◽  
Monique Lanouette ◽  
Roy Greenhalgh
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
High Pressure Liquid Chromatography ◽  
The Other ◽  
Average Level ◽  
Uv Detector ◽  
Reverse Phase ◽  
Technical Grade ◽  
Solvent Systems

Abstract Technical grade samples of fenitrothion were analyzed by high pressure liquid chromatography (HPLC) on a reverse phase LiChrosorb RP-8 column, using 3 solvent systems and a UV detector set at 269 nm. All commercial samples analyzed contained >94% fenitrothion; in addition, 9 contaminants were identified and quantitated. Bisfenitrothion was the major contaminant, with average amounts of 2.46% from one manufacturer and 1.17% from another. The second most abundant toxicant was S-methyl fenitrothion, which was present at an average level of 0.71% in one source but only 0.16% in the other. The amount of fenitrooxon was 0.046% or less in samples from 2 manufacturers. Other contaminants quantitated include the 2 demethyl fenitrothion isomers, 3-methyl-4-nitrophenol, 3-methyl-6-nitrophenol, 3-methyI-4-nitroanisole, and bis-S-methyl fenitrothion. The total amount of the constituents quantitated in 9 commercial samples was 99.07 ± 1.81%. By comparing the amounts of bis-fenitrothion and phenols present in technical grade fenitrothion, it should be possible to identify the specific manufacturers of the various products.

Determination of Zearalenone in Corn by High Pressure Liquid Chromatography and Fluorescence Detection

1978 ◽  
Vol 61 (5) ◽  
pp. 1058-1062
Author(s):  
George M Ware ◽  
Charles W Thorpe
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
High Pressure Liquid Chromatography ◽  
Fluorescence Detection ◽  
Hplc Analysis ◽  
Fluorescence Detector ◽  
Reverse Phase

Abstract A method is reported for determining zearalenone in corn at levels as low as 10 ng/g. Samples are extracted with chloroform-water and cleaned up by liquid-liquid chromatography, and the zearalenone is detected by a fluorescence detector after separation by reverse phase high pressure liquid chromatography (HPLC). Recoveries of zearalenone added to corn at levels from 10 to 200 ng/g averaged greater than 89%. In addition, a confirmation procedure is described which involves sequential HPLC analysis of the sample and a zearalenone standard, using 4 different excitation wavelengths and comparing fluorescence responses obtained. This method was successfully applied to the analysis of 11 samples of cornmeal; zearalenone was detected in 9 of the samples at levels from 11 to 69 ng/g.

A Simple Procedure for the Determination of Carbamazepine in Plasma by High Pressure-Liquid Chromatography

1979 ◽  
Vol 16 (1-6) ◽  
pp. 213-216 ◽  
Author(s):  
C. K. Johnston ◽  
G. H. Lester
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
High Pressure Liquid Chromatography ◽  
Mobile Phase ◽  
Simple Procedure ◽  
Internal Standard ◽  
Reverse Phase ◽  
Coefficients Of Variation ◽  
Initial Results

We describe a simple, rapid procedure for the estimation of carbamazepine in plasma. Protein is precipitated, and extraction is achieved by the addition of acetonitrile containing the internal standard N-acetyltryptophan ethyl ester. Separation is by reverse-phase high-pressure liquid chromatography with an acetonitrile: water mobile phase, and detection is by UV absorption at 280 nm. Total retention time is less than 7 minutes. Initial results gave within-batch and between-batch coefficients of variation of less than 2 %, and mean recovery of 97 %. The method is free from interference by other common anticonvulsant drugs.

GRP-related peptides in the rat retina: Characterisation by reverse-phase high pressure liquid chromatography

1987 ◽  
Vol 18 (5-6) ◽  
pp. 345
Author(s):  
J.M. McKillop ◽  
W.L. Foy ◽  
C. Shaw ◽  
C.F. Johnston ◽  
R.F. Murphy ◽  
...  
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
High Pressure Liquid Chromatography ◽  
Reverse Phase ◽  
Rat Retina
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