Enzymatic Determination of Cholesterol in Egg Yolk

1982 ◽  
Vol 65 (5) ◽  
pp. 1222-1224 ◽  
Author(s):  
Chih-Shang J Shen ◽  
Isabel S Chen ◽  
Alan J Sheppard
Keyword(s):  
Quantitative Determination ◽  
Methylene Chloride ◽  
Egg Yolk ◽  
Cholesterol Content ◽  
Enzymatic Determination ◽  
Test Kit ◽  
The Mean ◽  
Liquid Chromatographic ◽  
Enzymatic Test

Abstract The quantitative determination of cholesterol in egg yolk by using an enzymatic test kit is described. Cholesterol in the egg yolk is extracted with other lipid components by methylene chloride-methanol (2 + 1) and is enzymatically determined after saponification of the lipid extract. The method is relatively rapid, simple, and accurate and gives results which agree with those obtained by using a gas-liquid chromatographic (GLC) method. The mean cholesterol content of egg yolk determined by the enzymatic and GLC methods was 1237 and 1240 mg/100 g, respectively.

Gas-Liquid Chromatographic Quantitative Determination of Vanillin and Ethyl Vanillin in Foods

1974 ◽  
Vol 57 (2) ◽  
pp. 329-331
Author(s):  
Janis E Schlack ◽  
Joseph J Dicecco
Keyword(s):  
Quantitative Determination ◽  
Chromatographic Method ◽  
Methylene Chloride ◽  
Ethyl Vanillin ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic method for vanillin and ethyl vanillin in foods has been devised. Vanillin and ethyl vanillin are extracted into methylene chloride, and the extract is purified, concentrated, and then chromatographed on an EGSS-X column. Recovery of vanillin and ethyl vanillin averaged 99.54 and 98.05%, respectively.

Determination of Semduramicin Sodium in Poultry Liver by Liquid Chromatography with Vanillin Postcolumn Derivatization

1994 ◽  
Vol 77 (3) ◽  
pp. 577-582 ◽  
Author(s):  
Jon F Ericson ◽  
Albert Calcagni ◽  
Martin J Lynch
Keyword(s):  
Liquid Chromatography ◽  
Quantitative Determination ◽  
Solid Phase ◽  
Ammonium Hydroxide ◽  
Phase Extraction ◽  
Minimum Level ◽  
The Mean ◽  
Liquid Chromatographic ◽  
Postcolumn Derivatization

Abstract A liquid chromatographic (LC) method is described for the quantitative determination of semduramicin sodium in broiler liver when administered under projected use conditions. For this procedure, semduramicin sodium is extracted from liver with methanolic ammonium hydroxide, separated and concentrated by solid-phase extraction steps, and determined by LC with postcolumn derivatization with vanillin. The mean recovery of drug was 95% over the 40-320 ng/g range, the coefficient of variation was ±10% or better, and no interference was observed from commercial poly ether ionophores. The minimum level of detection for semduramicin sodium in broiler liver is 25 ng/g.

Liquid Chromatographic Determination of Cephapirin Residues in Milk

1990 ◽  
Vol 73 (6) ◽  
pp. 880-882 ◽  
Author(s):  
Agnes I Macintosh
Keyword(s):  
Quantitative Determination ◽  
Mobile Phase ◽  
Sodium Acetate ◽  
Methylene Chloride ◽  
Chromatographic Determination ◽  
Penicillin G ◽  
Uv Detector ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method was developed for quantitative determination of cephapirin residues In milk that also resolved cephapirin from amplcillln, cloxaclllin, and penicillin G. Diluted milk was passed through a C18 cartridge on which the cephapirin was adsorbed; then, Interfering material was removed by washing with water and methylene chloride and cephapirin residues were eluted with methanolacetonitrlle (25 + 75). After drying, residues were dissolved in the mobile phase for Injection. The LC system had an ultrasphere-ODS column with RP-18 Spherl-10 guard column and a UV detector with a 254 nm filter. The mobile phase was 85% sodium acetate (0.01M) and 15% methanol-acetonltrile (25 + 75) with a flow rate of 1 mL/mln. Sensitivity was 20 ppb or less with a recovery of 61-80% in the range studied. Other βlactam antibiotics tested did not Interfere with detection of cephapirin. Analysis of 30 samples of commercial homogenized milk obtained for a survey of antibiotics in consumer milk In Canada revealed no detectable cephapirin residues.

Determination of Hexachlorobenzene and Mirex in Fatty Products

1975 ◽  
Vol 58 (3) ◽  
pp. 557-561
Author(s):  
Rodney L Bong
Keyword(s):  
Petroleum Ether ◽  
Electron Capture ◽  
Methylene Chloride ◽  
Fats And Oils ◽  
Fat Injection ◽  
Liquid Chromatographic ◽  
Ppm Level

Abstract A procedure is described for the isolation and cleanup of hexachlorobenzene (HCB) and mirex in fats and oils for gas-liquid chromatographic (GLC) analysis. The fat or oil is distributed on unactivated Florisil, and the HCB and mirex are eluted with acetonitrile. The pesticides are then partitioned into petroleum ether. Elution through activated Florisil with methylene chloride-hexane (20+80) is used for the final cleanup. HCB and mirex are then measured by GLC, using the appropriate electron capture conditions with a 15% OV-210 column for HCB and a 3% OV-101 column for mirex. The method demonstrates recoveries greater than 90% for HCB and mirex and allows screening at or below the 0.1 ppm level in fats with a 3 mg fat injection.

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 Diazepam in Tablets: Collaborative Study

1985 ◽  
Vol 68 (3) ◽  
pp. 545-546
Author(s):  
Michael Tsougros
Keyword(s):  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Photometric Detection ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
The Mean ◽  
Liquid Chromatographic

Abstract A stability indicating liquid chromatographic method for the determination of diazepam in tablets was collaboratively studied by 6 laboratories. The method uses a Cig reverse phase column, a methanolwater mobile phase, p-tolualdehyde as the internal standard, and photometric detection at 254 nm. The collaborators were supplied with a synthetic tablet powder and 3 commercial tablet samples. The mean recovery of diazepam from the synthetic tablet powder was 100.2%. For all samples analyzed, the coefficient of variation was < 1.5%. The method has been adopted official first action.

Simultaneous Liquid Chromatographic Determination of Thiamine and Riboflavin in Selected Foods

1993 ◽  
Vol 76 (5) ◽  
pp. 1156-1160 ◽  
Author(s):  
Art Sims ◽  
Dirk Shoemaker
Keyword(s):  
American Association ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Fluorescence Detector ◽  
Liquid Chromatographic Determination ◽  
Optimum Wavelength ◽  
The Mean ◽  
Sensitivity Data ◽  
Liquid Chromatographic

Abstract A reliable, improved liquid chromatographic (LC) method has been developed for the measurement of thiamine and riboflavin in foods. The major improvement in the method is the chromatographic separation achieved. The method is also very reproducible and extremely sensitive. After autoclave extraction, samples are derivatized to form thiochrome (a highly fluorescent oxidation product of thiamine). Riboflavin is naturally fluorescent. Interferences are removed on a Ci8 cartridge and chromatographed by using a reversed-phase separation. The mobile phase used is 72% 0.005M NH4OAc (pH 5.0)-28% MeOH. Fluorescence detection using wavelength switching, 370-435 for thiamine and 370-520 for riboflavin, allows determination of each vitamin at its optimum wavelength for maximum sensitivity. Detection limits were 0.05 ng for both thiamine and riboflavin. The method can also be performed by using a fluorescence detector at a single wavelength, but with a sacrifice of sensitivity. Data comparisons between AOAC fluorometric and LC results were excellent for routine samples, as well as for American Association of Cereal Chemists (AACC) check samples. All LC results from AACC samples were within 2 standard deviations of the mean. Reproducibility was 1.9% for thiamine and 1.6% for riboflavin.

scholarly journals Solid-Phase Extraction and Gas Chromatography with Mass Spectrometric Determination of Capsaicin and Some of Its Analogues from Chili Peppers (Capsicum spp.)

1999 ◽  
Vol 82 (6) ◽  
pp. 1399-1405 ◽  
Author(s):  
Philemon Manirakiza ◽  
Adrian Covaci ◽  
Paul Schepens
Keyword(s):  
Gas Chromatography ◽  
Quantitative Determination ◽  
Solid Phase ◽  
Accurate Method ◽  
Mass Spectrometric ◽  
Phase Extraction ◽  
Capsicum Spp ◽  
The Mean ◽  
Chili Peppers

Abstract A rapid and accurate method has been developed for the quantitative determination of capsaicin and its most important analogues, dihydrocapsaicin and nordihydrocapsaicin in chili peppers. These components were extracted with methylene chlo ride and separated from interfering substances with activated charcoal. Further cleanup on Florisil cartridges and elution with ethyl acetate were performed before gas chromatographic with mass spectrometric quantitation. The concentrations found were 440 ± 64 μg/g capsaicin, 81 ± 10 μg/g dihydrocapsaicin, and 11 ± 2 μg/g nordihydrocapsaicin. The mean recovery values for triplicate analysis were between 85-94%.

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