Chloramphenicol Extraction from Milk by Using the Diphasic Dialysis Method Followed by Liquid Chromatographic Determination

1994 ◽  
Vol 77 (4) ◽  
pp. 854-856 ◽  
Author(s):  
Javier Bayo ◽  
Miguel A Moreno ◽  
Javier Prieta ◽  
Susana Díaz ◽  
Guillermo Suárez ◽  
...  
Keyword(s):  
Working Conditions ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Reversed Phase Liquid Chromatography ◽  
Simple Method ◽  
Dialysis Method ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract An economical, fast, and simple method for the extraction and liquid chromatographic determination of chloramphenicol (CAP) in milk is described. CAP is extracted by using a recently developed membrane-based method named “diphasic dialysis.” CAP is detected and quantitated in the organic solvent used in dialysis without additional cleanup steps by reversed-phase liquid chromatography and UV detection (270 nm). The determination imit of CAP in milk was about 5 μg/L, although as little as 1 μg/L could be detected under optimal working conditions.

Liquid Chromatographic Determination of 2-Chloro-4-nitroaniline, 2-Naphthol, and 2,4-Dinitroaniline in D&C Red No. 36

1993 ◽  
Vol 76 (2) ◽  
pp. 287-291 ◽  
Author(s):  
Alan L Scher ◽  
Nicholas C Adamo
Keyword(s):  
Chromatographic Determination ◽  
Reversed Phase ◽  
Calibration Data ◽  
Reversed Phase Liquid Chromatography ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Cellulose Column

Abstract A method is described for the determination of the intermediates and a related impurity in D&C Red No. 36 by reversed-phase liquid chromatography. This method may be used to ensure that limits set forth in the Code of Federal Regulations on the amounts of these 3 impurities in the color are not exceeded. The pigment is dissolved in boiling dioxane and then precipitated. The filtrate is chromatographed by isocratic elution, and then the column is washed and reequilibrated. Impurities were identified as 2-chloro-4-nitroaniline (2-CI-4-NA), 2-naphthol, and 2,4-dinitroaniline (2,4-DNA) by comparison of their retention times and spectra with those of standards. Peak area calibrations were linear to at least 0.375% 2-CI-4-NA, 1.25% 2-naphthol, and 0.025% 2,4-DNA, all with zero intercepts. At the specification levels, 99% confidence limits were 0.30 ± 0.006% for 2-CI-4-NA, 1.0 ± 0.03% for 2-naphthol, and 0.020 ± 0.0004% for 2,4-DNA. The limits of determination calculated from calibration data were 0.019% for 2-CI-4-NA, 0.10% for 2-naphthol, and 0.0014% for 2,4-DNA at the 99% confidence level. Recoveries were 100-104% for 2-CI-4-NA added to purified D&C Red No. 36,100% for 2-naphthol, and 100-110% for 2,4-DNA; relative standard deviations were 0.8-3.4%. A survey of certified D&C Red No. 36 samples showed that the batches contained higher levels of intermediates than were determined previously by a cellulose column method in which the pigment was not dissolved.

Liquid-chromatographic determination of cyclosporine in serum with use of a rapid extraction procedure.

1982 ◽  
Vol 28 (11) ◽  
pp. 2269-2271 ◽  
Author(s):  
G C Yee ◽  
D J Gmur ◽  
M S Kennedy
Keyword(s):  
Extraction Procedure ◽  
Chromatographic Determination ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Reversed Phase Liquid Chromatography ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Assay Methods ◽  
Liquid Chromatographic

Abstract In this procedure, reversed-phase liquid chromatography is used to measure cyclosporine, a fungal metabolite with immunosuppressive activity, in human serum. With a gradient elution, the retention times for cyclosporine and cyclosporin D were 14.1 and 15.7 min, respectively. Ultraviolet absorbance at 215 nm was used to detect cyclosporine; this wavelength improved assay accuracy without decreasing sensitivity, as compared with detection at 205 nm, which is near the absorption maximum. The major advantage of our procedure is the clean-up method, which involves use of disposable extraction columns. This extraction is simple and requires only 10 to 15 min per sample. Results by radioimmunoassay for cyclosporine were unpredictably greater than those measured by the present method. Dosing guidelines for cyclosporine need re-evaluation, based on more specific assay methods.

scholarly journals Liquid Chromatographic Determination of 4, 4' -Dinitrocarbanilide, the Active Component of the Infertility Agent Nicarbazin, in Chicken, Duck, Goose, and Snake Eggs

2003 ◽  
Vol 86 (6) ◽  
pp. 1144-1148
Author(s):  
Thomas M Primus ◽  
Dennis J Kohler ◽  
Margaret A Goodall ◽  
Christi Yoder ◽  
Thomas Mathies ◽  
...  
Keyword(s):  
Active Component ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Reversed Phase Liquid Chromatography ◽  
Ultraviolet Absorbance ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
The Mean ◽  
Liquid Chromatographic

Abstract 4, 4'-Dinitrocarbanilide (DNC) was extracted from chicken, duck, goose, and snake eggs and isolated by reversed-phase liquid chromatography. DNC was detected by ultraviolet absorbance at 347 nm and quantitated by comparison with a calibration standard. Recoveries of DNC from fortified control chicken, duck, goose, and snake egg samples were determined for DNC levels of 0.16, 10, and 16 μg/g. The mean recoveries from chicken, duck, goose, and snake eggs were 92 ± 4, 88 ± 9, 87 ± 7, and 95 ± 6%, respectively. The method limits of detection for DNC in chicken, duck, goose, and snake eggs ranged from 0.015 to 0.035 μg/g. The reported method is much simpler than and equally efficient as previous methods developed for the determination of DNC residues in egg contents.

Liquid Chromatographic Determination of Aflatoxins in Animal Feeds and Feed Components

1993 ◽  
Vol 76 (2) ◽  
pp. 366-370 ◽  
Author(s):  
Ivan Chang Yen ◽  
Keshore R Bidasee
Keyword(s):  
Liquid Chromatography ◽  
Chromatographic Determination ◽  
Chloroform Extract ◽  
Reversed Phase ◽  
Reversed Phase Liquid Chromatography ◽  
Animal Feeds ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A method is described for the determination of af latoxins B1, B2, G1, and G2 in animal feeds and feed components by liquid chromatography (LC) with fluorescence detection. In this modified procedure, the aflatoxins are extracted from the samples with methanol-water (75 + 25), and the solution is vacuum- filtered through Whatman No. 541 filter paper. An aliquot of the extract is first defatted with petroleum ether, and then the aflatoxins are partitioned into chloroform. The chloroform extract is purified on a silica gel chromatographic column, aflatoxins B1 and G1 are derivatized by trif luoroacetic acid to their hemiacetals, and the aflatoxins are determined by reversed-phase liquid chromatography. Recoveries from 11 samples ranged from 90 to 98% for aflatoxins B1 and G1 (spiking range 2-25 ng/g) and B2 and G2 (spiking range 0.2-2.5 ng/g).

Liquid Chromatographic Determination of Phosphamidon in Technical and Formulated Products: CIPAC Collaborative Study

1994 ◽  
Vol 77 (1) ◽  
pp. 8-10
Author(s):  
Alan R Hanks
Keyword(s):  
Collaborative Study ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Reversed Phase Liquid Chromatography ◽  
Buffer Solution ◽  
External Standard ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract Phosphamidon is determined by reversed-phase liquid chromatography on a C18 column with a mobile phase of acetonitrile—methanol buffer solution, detected by a UV absorbance detector set at 218 nm, and quantitated by area measurements using an external standard. The method was adopted first action by AOAC INTERNATIONAL.

Liquid Chromatographic Determination of Thiamine in Rodent Feed by Postcolumn Derivatization and Fluorescence Detection

1995 ◽  
Vol 78 (2) ◽  
pp. 307-309 ◽  
Author(s):  
Theresa A Gehring ◽  
Willie M Cooper ◽  
Claude L Holder ◽  
Harold C Thompson
Keyword(s):  
Chromatographic Determination ◽  
Reversed Phase ◽  
Detector Response ◽  
Fluorescence Excitation ◽  
Liquid Chromatographic Method ◽  
Essential Nutrient ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method was developed for determination of the essential nutrient thiamine (vitamin Bi) in rodent feed. Thiamine was extracted with hydrochloric acid, separated by reversed-phase liquid chromatography, derivatized postcolumn to thiochrome with potassium hydroxide and potassium ferricyanide, and detected by fluorescence. Excitation and emission wavelengths were 370 and 430 nm, respectively. Detector response was linear in the range of 2.58 to 15.5 ng of thiamine injected. Instrument detection limit was 5 pg of thiamine injected.

Reversed-Phase Liquid Chromatographic Determination of Hypoglycin A (HG-A) in Canned Ackee Fruit Samples

1994 ◽  
Vol 77 (5) ◽  
pp. 1175-1179 ◽  
Author(s):  
Ghulam Sarwar ◽  
Herbert G Botting
Keyword(s):  
Amino Acids ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Precolumn Derivatization ◽  
Edible Portion ◽  
Fruit Samples ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A reversed-phase liquid chromatographic (LC) method involving precolumn derivatization with phenylisothiocyanate (PITC) was developed for determining levels of hypoglycin A (HG-A) in canned ackee fruit samples. HG-A was extracted by homogenizing the drained fruit in 80% ethanol. By using a Waters Pico-Tag amino acid analysis 15-cm-long column (which is also used for analyzing protein hydrolysates and biological samples) and an LC system, the baseline separation of HG-A from other amino acids was completed in about 6 min. The total time for analysis and equilibration was 16 min. HG-A levels in the edible portion of fruit in 18 cans varied from 18.27 to 87.50 mg HG-A/can. Recoveries of added standard HG-A averaged 101%. To our knowledge, this is the first report of the use of this method to determine HG-A in ackee fruit.

scholarly journals Liquid Chromatographic/Mass Spectrometric Determination of Desmedipham and Phenmedipham and Their Metabolites in Soil

2001 ◽  
Vol 84 (5) ◽  
pp. 1407-1412 ◽  
Author(s):  
Daniela Perret ◽  
Alessandra Gentili ◽  
Stefano Marchese ◽  
Aldo Marino ◽  
Federica Bruno
Keyword(s):  
Reversed Phase ◽  
Soil Types ◽  
Liquid Chromatography Mass Spectrometry ◽  
Reversed Phase Liquid Chromatography ◽  
Soil Suspension ◽  
Simple Method ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Chromatographic Mass

Abstract A simple method is described for the simultaneous determination of residues of 2 carbamate herbicides (phenmedipham and desmedipham) and related metabolites (m-aminophenol, aniline, and m-toluidine) in soil. The analytes are extracted from spiked soils with methanol. The solvent/soil suspension is centrifuged, and the supernatant is directly injected, without any further cleanup, into a reversed-phase liquid chromatography/mass spectrometry apparatus equipped with a TurboIonSpray interface. The method was tested on 5 soils having different physicochemical properties. Recoveries from the soil types, spiked over the range of 50–200 ppb, were essentially quantitative for each analyte. The detection limits of the method are ≤25 ng/g.

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