Gas-Liquid Chromatographic Determination of Thiourea in Citrus Peels

1979 ◽  
Vol 62 (5) ◽  
pp. 1146-1154
Author(s):  
Masatake Toyoda ◽  
Shunjiro Ogawa ◽  
Yoshio Ito ◽  
Masahiro Iwaida
Keyword(s):  
Detection Limit ◽  
Sodium Sulfate ◽  
Sodium Carbonate Solution ◽  
Chromatographic Determination ◽  
Ether Extract ◽  
Alumina Column ◽  
Citrus Peels ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic (GLC) method was developed for the detection and determination of thiourea in citrus peels. After the peel is extracted with ethyl ether, the ether extract is adsorbed on sodium sulfate together with water. Thiourea is recovered from both the sodium sulfate and the peel residue with ethyl acetateacetone( 2+l). The extracted mixture is cleaned on an alumina column, the eluate is concentrated under vacuum, and thiourea is extracted from the concentrate with sodium carbonate solution. GLC was carried out on the prepared benzoyl derivative of thiourea. The average recoveries of thiourea from lemon peel were 85.3, 93.1, and 97.6% at the fortification levels of 1, 10, and 100 ppm, respectively. The detection limit was as low as 0.08 ppm.

Liquid Chromatographic Determination of Sulfamoyldapsone in Swine Tissues

1987 ◽  
Vol 70 (6) ◽  
pp. 1031-1032
Author(s):  
Yuuko S Endoh ◽  
Ryozo Yamaoka ◽  
Nobuo Sasaki
Keyword(s):  
Detection Limit ◽  
Quantitative Determination ◽  
Chromatographic Determination ◽  
Alumina Column ◽  
Average Recovery ◽  
Diaminodiphenyl Sulfone ◽  
Alumina Column Chromatography ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method is described for the quantitative determination of sulfamoyldapsone (2-sulfamoyl-4,4'-diaminodiphenyl sulfone) in swine muscle, liver, kidney, and fat. Sulfamoyldapsone was extracted from tissues with acetonitrile saturated with n-hexane. The extract was washed with n-hexane saturated with acetonitrile, concentrated, and cleaned up by alumina column chromatography. Sulfamoyldapsone was separated on an ODS column by using acetonitrile-methanol-water (6 + 18 + 76) and was detected at 292 nm. Overall average recovery of sulfamoyldapsone added to tissues at levels of 0.1 and 0.5 /μg/g was 93.3% ± 6.0. Detection limit was 0.02 μg/g in these tissues.

Liquid Chromatographic Determination of the Herbicide Isoxaben and Its Soil Metabolite in Soil and Soil-Turf Samples

1990 ◽  
Vol 73 (2) ◽  
pp. 287-289 ◽  
Author(s):  
Bonnie S Rutherford
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
Column Chromatography ◽  
Chromatographic Determination ◽  
Alumina Column ◽  
Alumina Column Chromatography ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A method Is described for the determination of residues of isoxaben and its principal soil metabolite In soil and soil-turf samples. Both compounds are extracted from samples by refluxing with methanol-water. An aliquot of the extract Is partitioned Into dichloromethane and purified by alumina column chromatography. Separate fractions containing isoxaben and metabolite are collected and subjected to liquid chromatography at conditions that are optimized for each compound. The detection limit for both compounds is 0.005 ppm. Residue identities are confirmed by chromatography on a different LC system.

Improved Method for Gas-Liquid Chromatographic Determination of Clopidol in Chicken Tissues

1980 ◽  
Vol 63 (6) ◽  
pp. 1211-1214
Author(s):  
Etsuko Suzuki ◽  
Mihoko Matsuda ◽  
Atsushi Momose ◽  
Masaya Namekata
Keyword(s):  
Exchange Resin ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Alumina Column ◽  
Resin Column ◽  
Chicken Tissues ◽  
Liquid Chromatographic Determination ◽  
Low Levels ◽  
Liquid Chromatographic

Abstract A sensitive and specific gas-liquid chromatographic (GLC) method has been developed for determining low levels of clopidol in chicken tissues. Clopidol is extracted from the tissues with methanol, and cleaned up on an alumina column and an anion exchange resin column with 0.1% acetic acid–methanol as eluate. Clopidol is methylated with diazomethane, and then determined by GLC. 2,4-Dinitro-l-chlorobenzene is used as an internal standard. The method is applicable to levels as low as 2 ppb in chicken tissues. Recoveries of 2–20 ppb clopidol added to tissues averaged 87% for muscle, 84% for liver, 80% for kidney, and 76% for fat.

Liquid Chromatographic Determination of Fluridone Aquatic Herbicide and Its Metabolite in Fish and Crayfish

1986 ◽  
Vol 69 (5) ◽  
pp. 856-859 ◽  
Author(s):  
Sheldon D West ◽  
Edgar W Day
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Reverse Phase Liquid Chromatography ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Aquatic Herbicide ◽  
Liquid Chromatographic

Abstract A residue method is described for determination of the aquatic herbicide fluridone (1-methy1-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)- pyridinone) and its metabolite (1-methy1-3-(4-hydroxyphenyl)-5-[3- (trifluoromethyl)phenyl]-4(1H)-pyridinone) in fish and crayfish tissues. Both compounds are extracted from tissues with methanol, and the extracts are subjected to acidic hydrolysis to release conjugated forms of fluridone and the metabolite. Sample extracts are purified by liquidliquid partitioning and Florisil Sep-Pak® column chromatography. Both compounds are separated and measured by reverse phase liquid chromatography with UV detection at 313 nm. In the absence of interfering peaks, the method has a detection limit of approximately 0.04 ppm of either compound. Overall, recoveries averaged 96% for fluridone and 78% for the metabolite for all tissue types combined.

Liquid Chromatographic Determination of Bromide Ion in Cereals, Fruit, Vegetables, and Blood with a Silver Electrode in an Electrochemical Detector System

1995 ◽  
Vol 78 (3) ◽  
pp. 841-845 ◽  
Author(s):  
Bertil Lindgren ◽  
Tomas Berglöf ◽  
Åsa Ramberg ◽  
Anna Stepdmska ◽  
Malin Åkerblom
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
Rapid Determination ◽  
Chromatographic Determination ◽  
Electrochemical Detector ◽  
Satisfactory Precision ◽  
Bromide Ion ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A method is presented for rapid determination of bromide ion in commodities and blood by paired-ion liquid chromatography with electrochemical detection. The method involves extraction of samples with water and filtration. Blood is passed through a Sep-Pak C18 minicolumn. Recoveries are usually close to 100%, with satisfactory precision. The detection limit is 1 mg/kg. The method needs little labor and uses no noxious solvents or reagents.

Liquid Chromatographic Determination of Spiramycin Residues in Chicken Tissues

1986 ◽  
Vol 69 (4) ◽  
pp. 644-646
Author(s):  
Tomoko Nagata ◽  
Masanobu Saeki
Keyword(s):  
Detection Limit ◽  
Ethyl Ether ◽  
Chromatographic Determination ◽  
Chicken Tissues ◽  
Chicken Muscles ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method is described for determination of spiramycin residues in chicken muscles. The drug is extracted from muscles with acetonitrile, the extract is concentrated to 3-4 mL and rinsed with n-hexane followed by ethyl ether, and the drug is extracted with chloroform. LC analysis is carried out on a Zorbax BP-C8 column, and spiramycin is detected spectrophotometrically at 231 nm. Recoveries of spiramycin added to chicken muscles at 0.2 and 0.1 ppm were 93.9 and 89.0%, respectively. The detection limit was 5 ng for spiramycin standard, and 0.05 ppm in chicken muscles.

Semiautomated Liquid Chromatographic Determination of Clopidol in Poultry Feed

1971 ◽  
Vol 54 (3) ◽  
pp. 551-554 ◽  
Author(s):  
N E Skelly ◽  
R F Cornier
Keyword(s):  
Ion Exchange ◽  
Methanol Extract ◽  
Chromatographic Determination ◽  
Poultry Feed ◽  
Alumina Column ◽  
Accuracy And Precision ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Ppm Level

Abstract A semiautomated ion exchange-ultraviolet procedure has been developed for the determination of clopidol in poultry feed at the 40–250 ppm level. A methanol extract of the feed is injected into an alumina precolumn to remove interferences. The clopidol passes through the alumina column and is collected on an ion exchange column. With a specially designed elution apparatus the clopidol is removed by an acetic acid-methanol gradient. The eluate proceeds through a flowcell mounted in an ultraviolet spectrophotometer. Response of the spectrophotometer is monitored by a recorder. Concentration is determined by comparing the peak area in the resulting chromatogram with that of a standard. Accuracy and precision of this method are ±5% relative to the amount present (100±5 ppm).

Liquid Chromatographic Determination of Carbadox Residues in Animal Feed

1985 ◽  
Vol 68 (4) ◽  
pp. 653-657
Author(s):  
Jose E Roybal ◽  
Robert K Munns ◽  
Wilbert Shimoda
Keyword(s):  
Animal Feed ◽  
Chromatographic Determination ◽  
Alumina Column ◽  
Acid Base ◽  
Reverse Phase ◽  
Liquid Chromatographic Determination ◽  
Swine Feed ◽  
Liquid Chromatographic ◽  
Base Liquid

Abstract A liquid chromatographic (LC) method for determining residues of carbadox in the 0.01-10 ppm range in swine feed is described. Carbadox is extracted from ground feed with 25% acidified methanol- CHCl3, removed from emulsion-forming coextractables via an alumina column, separated from highly colored pigments by acid-base liquid- , liquid partitioning, and finally isolated from interferences on a second | alumina column. Isocratic reverse phase LC at 305 nm is used for quantitation. The average overall recovery at the 0.1,0.5, and 1.0 ppm J spike levels was 83.0% with a standard deviation of 2.04% and a coefficient of variation of 2.46 %.

Liquid Chromatographic Determination of Amprolium in Chicken Tissues, Using Post-Column Reaction and Fluorometric Detection

1986 ◽  
Vol 69 (6) ◽  
pp. 941-943
Author(s):  
Tomoko Nagata ◽  
Masanobu Saeki
Keyword(s):  
Aqueous Solution ◽  
Reaction System ◽  
Chromatographic Determination ◽  
Fluorometric Detection ◽  
Alumina Column ◽  
Alumina Column Chromatography ◽  
Chicken Muscles ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A method is presented for determination of amprolium residues in chicken muscles by a liquid chromatographic post-column reaction system. The drug is extracted from muscles with methanol, and the extract is concentrated to 3-4 mL. This aqueous solution is rinsed with n-hexane and cleaned up by alumina column chromatography. The drug is separated from the interferences on a LiChrosorb RP-8 column, reacted with ferricyanide in alkaline solution, and quantitated by fluorometric detection at 367 nm (excitation) and 470 nm (emission). Recoveries of amprolium added to chicken muscles at levels of 0.1 and 0.2 ppm were 74.9 and 80.9%, respectively. The detection limit was 1 ng for amprolium standard and 0.01 ppm in chicken muscles.

Liquid Chromatographic Determination of Carhadox in Complete Feeds, Premixes, and Concentrates: Interlaboratory Study

1988 ◽  
Vol 71 (3) ◽  
pp. 484-490
Author(s):  
René M L Aerts ◽  
Geziena A Werdmuller
Keyword(s):  
Chromatographic Determination ◽  
Interlaboratory Study ◽  
Alumina Column ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
A Minor ◽  
Liquid Chromatographic ◽  
Feed Samples

Abstract A liquid chromatographic (LC) method previously published for the determination of carbadox in finished feeds and premixes was slightly modified and tested in an interlaboratory study. The feed samples are extracted with methanol-acetonitrile (50 + 50) after wetting with water. The extracts are purified over a short alumina column. An aliquot of the eluate is analyzed with reverse phase liquid chromatography with ultraviolet detection. Before the actual interlaboratory study, a prestudy with 2 familiarization feed samples was performed. For the interlaboratory study, 2 series of meal and pelleted samples were prepared with carbadox from different suppliers. Eight collaborating laboratories received 6 feed samples previously milled and ground and 4 pelleted samples which had to be ground by the collaborator's in-house method. Collaborators also received 3 carbadox concentrates (about 10% w/w) and 4 premix samples derived from the concentrates (about 1% w/w). Coefficients of variation under reproducibility conditions were 8.3% for meal samples and 4.9% for pellets. A minor but significant effect was noted for the influence of pelleting temperature on the carbadox content. A minor and insignificant effect was observed for the influence of the milling and grinding procedure on the carbadox content. Alumina cleanup of 1% premixes was not essential, although the resulting chromatograms were cleaner. A slight difference in reproducibility was observed with concentrates (10%) when 0.2 or 0.5 g sample size was used, although the average carbadox concentration found was the same. For premixes and concentrates, coefficients of variation under reproducibility conditions were low, ranging from 2.9 to 7.5%.

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