Modified Method for Electron Capture Gas-Liquid Chromatographic Determination of Diethylstilbestrol Residues in Urine of Fattened Bulls

1983 ◽  
Vol 66 (5) ◽  
pp. 1230-1233
Author(s):  
Athanasios E Tirpenou ◽  
Stylianos D Kilikidis ◽  
Athanasios P Kamarianos
Keyword(s):  
Sodium Hydroxide ◽  
Electron Capture ◽  
Silica Gel ◽  
Chromatographic Determination ◽  
Trifluoroacetic Anhydride ◽  
Phenolic Fraction ◽  
Modified Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic (GLC) method with electron capture (EC) detection was developed fof determining diethylstilbestrol residues in the urine of fattened bulls. Diethylstilbestrol (DES) is extracted into benzene, and then into IN sodium hydroxide. The pH of the phenolic fraction (alkaline phase) is adjusted to 10.2 and DES is extracted again into benzene. Sample extracts are cleaned up on silica gel. Trifluoroacetic anhydride (TFAA) is used as acylation reagent, and the derivatized sample is chromatographed on a 3% OV-17 column and measured with a 63Ni EC detector. The method is suitable for determining residues at levels as low as 2 ppb.

Modified Method for Electron Capture Gas-Liquid Chromatographic Determination of Hexestrol Residues in Bovine Tissues

1978 ◽  
Vol 61 (5) ◽  
pp. 1054-1057
Author(s):  
Hisaya Tobioka ◽  
Ryoji Kawashima
Keyword(s):  
Electron Capture ◽  
Chromatographic Determination ◽  
Electron Capture Detection ◽  
Purification Step ◽  
Packing Materials ◽  
Modified Method ◽  
Extraction And Purification ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic (GLC) method with electron capture detection was developed for determining hexestrol residues based on a GLC method for diethylstilbestrol residues. The extraction and purification procedures were based on a published procedure. Pentafluoropropionic (PFP) and heptafluorobutyric (HFB) anhydrides and other halogenated compounds were compared as acylation reagents. PFP anhydride was selected because it provided reproducible GLC responses. Of the 3 column packing materials tested, OV-17, OV-210, and QF-1, OV-17 was the most stable under the GLC conditions used. A pH 10.5—10.6 in the purification step gave higher recoveries than pH 10.3 or pH 10.8 and was selected for use. The method is suitable for determining residues of 0.5 ppb. The limit of sensitivity ranges from 0.1 to 0.2 ppb.

Gas-Liquid Chromatographic Determination of Residues from the Herbicide 2-Chloro-l-(3-Ethoxy-4-Nitrophenoxy)-4-(Trifluoromethyl) Benzene

1978 ◽  
Vol 61 (3) ◽  
pp. 636-639 ◽  
Author(s):  
Irving L Adler ◽  
Linwood D Haines ◽  
Brent Marco Jones
Keyword(s):  
Liquid Chromatography ◽  
Sodium Hydroxide ◽  
Methanol Extract ◽  
Chromatographic Determination ◽  
Extraction Process ◽  
Gas Liquid Chromatography ◽  
Simultaneous Distillation Extraction ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Residues of 2 - chloro - 1 - (3 - ethoxy- 4 - nitrophenoxy)-4-(trifluoromethyl) benzene and reduced metabolites are determined by digesting a sample methanol extract with aluminum in aqueous 10% sodium hydroxide to convert residues to 4-[2-chloro-4-(trifluoromethyl)-phenoxy]-2-ethoxybenzenamine. This compound is partitioned into hexane, using a simultaneous distillation-extraction process. The heptafluorobutyryl derivative is then prepared, partially purified by chromatography on Florisil, and measured by electron capture gas-liquid chromatography. The method is sensitive to 0.01 ppm.

Isolation, Purification, and Liquid Chromatographic Determination of Stilbene Phytoalexins in Peanuts

1995 ◽  
Vol 78 (5) ◽  
pp. 1177-1182 ◽  
Author(s):  
Victor S Sobolev ◽  
Richard J Cole ◽  
Joe W Dorner ◽  
Boris Yagen
Keyword(s):  
Acetic Acid ◽  
Silica Gel ◽  
Mobile Phase ◽  
High Speed ◽  
Chromatographic Determination ◽  
Normal Phase ◽  
Phase Partition ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method for determination of stilbene phytoalexins (SPs) in peanuts has been developed. SPs were extracted with acetonitrile–water (90 + 10, v/v) by high-speed blending. An aliquot of extract was applied to a minicolumn packed with AI2O3–ODS (C18) mixture and eluted with acetonitrile-water (90 + 10, v/v). Eluate was evaporated under nitrogen, and residue was dissolved in LC mobile phase. SPs in an aliquot of purified extract were quantitated by normal-phase partition LC on silica gel with n-heptane–2-propanol–water–acetonitrile–acetic acid (1050 + 270 + 17 + 5 + 1, v/v) as mobile phase. Recoveries of SPs [frans-4-(3-methyl-but-1-enyl)-3,5,4′-trihy-droxystilbene (trans-arachidin-3; t-Ar-3), trans-3-isopentadienyl-4,3′,5′-trihydroxystilbene (t-IPD), and trans-3,5,4′-trihydroxystilbene (trans-resveratrol; t-Res)] from peanuts spiked at 300 ppb were 96.05 ± 2.8%. Limits of quantitation for t-Ar-3 and t-IPD were about 100 ppb. t-Ar-3, t-IPD, and t-Res were found in all parts of the peanut plant as major SPs produced in response to fungal invasion.

Gas-Liquid Chromatographic Determination of Permethrin in Bovine Tissues

1979 ◽  
Vol 62 (6) ◽  
pp. 1309-1311
Author(s):  
Delbert D Oehler
Keyword(s):  
Liquid Chromatography ◽  
Electron Capture ◽  
Chromatographic Determination ◽  
Chromatographic Column ◽  
Gas Liquid Chromatography ◽  
Florisil Column ◽  
Bonded Phase ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A method is presented for the determination of permethrin (m-phenoxybenzyl cis,trans-(±)-3-(2,2-dichlorovinyl) - 2,2 - dimethylcyclopropanecarboxylate) in bovine tissues. Fat and muscle samples were cleaned up first by liquid-liquid partition on a bonded phase chromatographic column. Final cleanup of fat and muscle was performed on a short Florisil column. Liver, kidney, spleen, and heart tissues only required cleanup on a Florisil column before quantitation of permethrin by electron capture gas-liquid chromatography.

High Pressure Liquid Chromatographic Determination of Xanthomegnin in Corn

1978 ◽  
Vol 61 (3) ◽  
pp. 590-592
Author(s):  
Michael E Stack ◽  
Nathan L Brown ◽  
Robert M Eppley
Keyword(s):  
High Pressure ◽  
Silica Gel ◽  
Chromatographic Determination ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatograph ◽  
High Pressure Liquid Chromatograph ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Layer Chromatography

Abstract A method is described for the detection and quantitative analysis of xanthomegnin in corn samples. Initial extraction with CHCI3 in the presence of 0.5M H3PO4 is followed by additional purification using silica gel column chromatography. A high pressure liquid chromatograph equipped with a microparticle silica gel column and a 405 nm absorbance detector is used for detection and quantitation of the xanthomegnin. The identity of xanthomegnin is confirmed by thin layer chromatography on silica gel plates developed with benzenemethanol- acetic acid (90-(-5+5). The recovery of xanthomegnin added to corn samples at levels of 0.75–9.6 mg/kg averaged 41% with a coefficient of variation of 25%.

Gas-Liquid Chromatographic Determination of Captan and Two Metabolites in Milk and Meat

1977 ◽  
Vol 60 (3) ◽  
pp. 679-681
Author(s):  
John H Onley
Keyword(s):  
Ethyl Acetate ◽  
Silica Gel ◽  
Chromatographic Determination ◽  
Gel Chromatography ◽  
Milk Samples ◽  
Liquid Chromatographic Determination ◽  
Meat Samples ◽  
Silica Gel Chromatography ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic (GLC) method has been developed for the determination of captan (N-trichloromethylthio-4-cyclohexene-1, 2-dicarboximide) and 2 metabolites, tetrahydrophthalimide (THPI) and tetrahydrophthalamic acid (THPMA), in milk and meat. The sample is extracted with ethyl acetate and is cleaned up by acetonitrile partition and silica gel chromatography where captan, THPI, and THPMA are separated. Captan is directly determined by GLC. THPI and THPMA are separately derivatized in an acetone solution of penta fluorobenzyl bromide. The resultant derivatives are purified separately on an Al2O3, column and quantitated by GLC, using an electron capture detector. Recoveries from milk samples fortified at 0.02–10 ppm ranged from 71 to 102%; recoveries from meat samples fortified at 0.04–10 ppm ranged from 75 to 99%.

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