Isolation of polychlorinated dibenzodioxins and polychlorinated dibenzofurans from a complex organic mixture by two-step liquid-chromatographic fractionation for quantitative analysis

1984 ◽  
Vol 56 (13) ◽  
pp. 2442-2447 ◽  
Author(s):  
H. Y. Tong ◽  
D. L. Shore ◽  
F. W. Karasek
Keyword(s):  
Quantitative Analysis ◽  
Polychlorinated Dibenzofurans ◽  
Organic Mixture ◽  
Chromatographic Fractionation ◽  
Polychlorinated Dibenzodioxins ◽  
Liquid Chromatographic ◽  
Complex Organic

Mass balance of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzodioxins (PCDDs) in a recycling paper mill

Chemosphere ◽  
1994 ◽  
Vol 28 (9) ◽  
pp. 1633-1639 ◽  
Author(s):  
Helmut Santl ◽  
Albert Bichlmaier ◽  
Ludwig Gruber ◽  
Elke Stöhrer
Keyword(s):  
Mass Balance ◽  
Paper Mill ◽  
Polychlorinated Dibenzofurans ◽  
Polychlorinated Dibenzodioxins

THE CHEMISTRY OF THE INDOLE GRIGNARD REAGENT: I. THE REACTION OF INDOLE MAGNESIUM IODIDE WITH ETHYL CHLOROFORMATE

1966 ◽  
Vol 44 (23) ◽  
pp. 2805-2811 ◽  
Author(s):  
S. Kašpárek ◽  
R. A. Heacock
Keyword(s):  
Quantitative Analysis ◽  
Low Temperatures ◽  
Grignard Reagent ◽  
Ethyl Chloroformate ◽  
Qualitative And Quantitative Analysis ◽  
Qualitative And Quantitative ◽  
Liquid Chromatographic

In contrast to previous reports in the literature, it has been shown that both 1- and 3-carbethoxyindole are obtained from the reaction of indole magnesium iodide with 1 or 2 moles of ethyl chloroformate. The formation of 1-carbethoxyindole was favored at low temperatures (i.e. −10°), whereas maximum yields of 3-carbethoxyindole were obtained at 10°. Significant quantities of 1,3-dicarbethoxyindole are only formed in the presence of 2 equivalents of ethyl chloroformate and when the reaction is carried out at higher temperatures (i.e. 35°).Paper and gas–liquid chromatographic systems have been developed for the qualitative and quantitative analysis of mixtures containing indole, 1-, 2-, and 3-carbethoxyindole, and 1,3-dicarbethoxyindole.

High-Speed Liquid Chromatographic Determination of o-Phenylphenol Residues in Citrus Products

1976 ◽  
Vol 59 (1) ◽  
pp. 162-164
Author(s):  
Samuel K Reeder
Keyword(s):  
Liquid Chromatography ◽  
Quantitative Analysis ◽  
High Speed ◽  
Steam Distillation ◽  
Chromatographic Determination ◽  
Analysis Time ◽  
Hexane Extraction ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A method is presented for the quantitative analysis of o-phenylphenol residues in citrus oils, encapsulated flavors, and dried meal. The method utilizes high-speed liquid chromatography for the determination after specific sample preparations for each material. These preparations include hexane extraction of acidified basic extracts or steam distillation and extraction. The limit of the analysis is <1 ppm with an analysis time of <45 min.

Determination of Melengestrol Acetate in Feedstuffs with Liquid Chromatographic Preparatory Column Cleanup and Quantitative Analysis

1988 ◽  
Vol 71 (4) ◽  
pp. 707-709
Author(s):  
Jim L Weigand ◽  
Daniel S Dille
Keyword(s):  
Liquid Chromatography ◽  
Quantitative Analysis ◽  
Sodium Sulfate ◽  
Alumina Column ◽  
Melengestrol Acetate ◽  
Preparative Lc ◽  
Time Savings ◽  
Commercial Feeds ◽  
Liquid Chromatographic

Abstract Melengestrol acetate (MGA) is determined by liquid chromatography using a fraction from preparatory LC as a means of sample cleanup for feedstuffs, both dry and liquid. Dry ground feed is Soxhlet extracted with hexane and passed through a 2% deactivated alumina column for initial cleanup. The eluate is evaporated, redissolved in methanol, filtered, and injected onto a preparatory LC column. The fraction containing MGA is separated from the remaining matrix, evaporated to dryness, dissolved in methanol, and quantitated by LC analysis. Liquid supplements are extracted in methanol, and the extract is evaporated to near dryness. The residue is diluted with water, extracted with chloroform, passed through sodium sulfate, and evaporated to dryness. The remaining sample is dissolved in methanol prior to preparative LC and quantitative LC. Recoveries for 2 laboratory- fortified commercial feeds, one dry and one liquid, containing 0.39 and 0.40 mg/lb, were 98.3% ± 4.4 and 95.8% ± 4.3, respectively. Results compare favorably with existing methods. Up to a 4-fold time savings was realized by this method without automation.

Foam-Charcoal Chromatography for Analysis of Polychlorinated Dibenzodioxins in Herbicide Orange

1978 ◽  
Vol 61 (1) ◽  
pp. 32-38
Author(s):  
James N Huckins ◽  
David L Stalling ◽  
William A Smith
Keyword(s):  
Electron Capture ◽  
Polyurethane Foams ◽  
Dichlorophenoxyacetic Acid ◽  
Activated Alumina ◽  
Average Recovery ◽  
Polychlorinated Dibenzodioxins ◽  
Butyl Esters ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Liquid Chromatographic ◽  
Additional Sample

Abstract Herbicide Orange (HO) is a mixture of n-butyl esters of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). The 2,4,5-T is known to contain 2,3, 7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and other chlorinated aromatic contaminants. Adsorption of TCDD from HO on small amounts of powdered charcoal results in sample cleanup adequate for electron capture gas-liquid chromatographic (GLC) analysis. Column flow restrictions with powdered charcoal are overcome by using polyurethane foams as a dispersive support, HO is dissolved in chloroform and percolated through a column containing a mixture of PX-21 activated carbon suspended on clean polyurethane foam (14.9% charcoal/ 85.1% foam, w/w). Subsequently, the column is washed with benzene, and TCDD is recovered with toluene-benzene (1+1). Samples containing less than 1 μg TCDD/ml required additional sample cleanup on activated alumina prior to GLC analysis. The average recovery of TCDD determined from 4 replicate radiometric measurements was 91.4% (standard error = 4.0). TCDD residues greater than 0.02 μg/ml in HO samples were quantitated by electron capture GLC after cleanup. The presence of TCDD and pentachlorodibenzo-p-dioxin was confirmed by GLC-mass spectroscopy. In addition, tetrachloro- and pentachlorodibenzofurans were inferred by GLC-mass spectrometry.

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