Determination of serum retinol (vitamin A) by high-speed liquid chromatography.

1976 ◽  
Vol 22 (10) ◽  
pp. 1593-1595 ◽  
Author(s):  
M G De Ruyter ◽  
A P De Leenheer
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
Vitamin A ◽  
High Speed ◽  
Serum Retinol ◽  
Lower Detection Limit ◽  
Serum Pool ◽  
Lower Detection ◽  
Liquid Chromatographic

Abstract We report a fast and simple high-speed liquid-chromatographic assay for serum retinol. Only 100 mul of serum is required. The lower detection limit is 50 mug/liter; linearity was demonstrated up to 1.50 mg/liter. On analyzing a serum pool eight times, a CV of 2.5% was obtained. Values by this method are compared with results obtained by a flurometric method [Clin. Chem. 16, 766(1970)].

High-Speed Liquid Chromatographic Cleanup of Environmental Samples Prior to the Gas Chromatographic Determination of Lindane

1974 ◽  
Vol 57 (5) ◽  
pp. 1046-1049
Author(s):  
Richard H Larose
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
Environmental Samples ◽  
High Speed ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Liquid Chromatograph ◽  
Cleanup Procedure ◽  
Liquid Chromatographic

Abstract A method is described which permits the removal of interfering co-extractives from lindane, using high-speed liquid chromatography. Fractions are collected from the liquid chromatograph for further analysis by gas-liquid chromatography. The cleanup procedure takes less than 5 min and recoveries of more than 90% are obtained. The detection limit for water samples is 5 ng/L.

Determination of Ethylene Oxide and Ethylene Chlorohydrin in Plastic and Rubber Surgical Equipment Sterilized with Ethylene Oxide

1970 ◽  
Vol 53 (2) ◽  
pp. 263-267
Author(s):  
Daniel J Brown
Keyword(s):  
Detection Limit ◽  
Ethylene Oxide ◽  
Chromatographic Analysis ◽  
Ethylene Chlorohydrin ◽  
Surgical Equipment ◽  
Lower Detection Limit ◽  
Lower Detection ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic

Abstract A method is presented for the determination of ethylene chlorohydrin and ethylene oxide residues in plastic and rubber surgical equipment. Samples are extracted with p-xylene and the desired constituents are isolated by column chromatography. Ethylene oxide is converted to ethylene chlorohydrin on a Celite column. Sweep co-distillation is then employed for further purification, if necessary, before gas-liquid chromatographic analysis. The lower detection limit is approximately 25 ng. Recoveries of 3.5’50 ppm chlorohydrin from 20’35 g samples range from 64 to 100%, depending on the absorbing capacity of the material being analyzed and the condition of the adsorbent.

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.

Simultaneous determination of retinol and retinyl esters in serum or plasma by reversed-phase high-performance liquid chromatography.

1978 ◽  
Vol 24 (11) ◽  
pp. 1920-1923 ◽  
Author(s):  
M G DeRuyter ◽  
A P De Leenheer
Keyword(s):  
Vitamin A ◽  
High Performance ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Retinyl Palmitate ◽  
Serum Retinol ◽  
Liquid Chromatographic Determination ◽  
Retinyl Esters ◽  
Liquid Chromatographic

Abstract We propose a single-run liquid-chromatographic determination, with ultraviolet detection at 330 nm, for serum retinol and retinyl esters. The vitamin A derivatives are extracted according to the Bligh-Dyer procedure. With 200 microliter or serum, the lower detection limit is 50 microgram/liter for retinol and about 100 microgram/liter for retinyl esters. Within-run precision (CV) was 2.3% for retinol, 4.3% for retinyl palmitate. Day-to-day percision (CV, n = 20) for retinol was 4.9% during a month. The method can be used for the assessment of vitamin A absorption tests and for the determination of serum retinol (normal, subnormal, and above-normal concentrations). Serum retinyl esters can only be measured in conditions where concentrations exceed 100 microgram/liter.

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.

Improved Spectrophotometric Determination of Cyclopiazonic Acid in Poultry Feed and Corn

1990 ◽  
Vol 73 (2) ◽  
pp. 257-259 ◽  
Author(s):  
Ivan Chang-Yen ◽  
Keshore Bidasee
Keyword(s):  
Detection Limit ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Cyclopiazonic Acid ◽  
Poultry Feed ◽  
Reaction Conditions ◽  
Lower Detection Limit ◽  
Lower Detection ◽  
Feed Samples

Abstract An improved visible spectrophotometric method has been developed for cyclopiazonic acid in poultry feed and corn. The method Is based on the reaction of cyclopiazonic acid with Ehrlich reagent and detection at 580 nm. Reaction conditions were optimized with respect to reaction and measurement times and acid and Ehrlich reagent concentrations. Calibration curves were linear from 1 to 20 μg cyclopiazonic acid in 3 mL Ehrlich reagent, with a lower detection limit of 0.08 mg/kg for 50 g samples of poultry feed and corn. Recoveries from 50 g samples of poultry feed spiked with cyclopiazonic ranging from 0.16 to 1.20 mg/kg averaged 93.8%. Moldy corn and poultry feed samples analyzed by this method contained between 1 and 4 mg/kg cyclopiazonic acid.

Determination of Ampicillin Residues in Fish Tissues by Liquid Chromatography

1986 ◽  
Vol 69 (3) ◽  
pp. 448-450 ◽  
Author(s):  
Tomoko Nagata ◽  
Masanobu Saeki
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
Fish Tissues ◽  
Ultraviolet Detection ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method is described for determination of ampicillin residues in fish tissues. The drug is extracted from tissues with methanol, and the extract is evaporated to dryness. This residue is cleaned up by Florisil cartridge chromatography. LC analysis is carried out on a Nucleosil C18 column, and ampicillin is quantitated by ultraviolet detection at 222 nm. Recoveries of ampicillin added to tissues at levels of 0.2 and 0.1 ppm were 73.2 and 61.5%, respectively. The detection limit was 3 ng for ampicillin standard, and 0.03 ppm in tissues.

High-Speed Liquid Chromatographic Determination of Biphenyl Residues in Citrus Products

1975 ◽  
Vol 58 (5) ◽  
pp. 1013-1014
Author(s):  
Samuel K Reeder
Keyword(s):  
Liquid Chromatography ◽  
Rapid Method ◽  
Orange Juice ◽  
High Speed ◽  
Extraction Procedure ◽  
Chromatographic Determination ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple, direct, and rapid method is given for the analysis of citrus oils for the fungistat biphenyl by high-speed liquid chromatography. The method is extended to orange juice and various “dry flavors” by an extraction procedure. Analytical limits are <1 ppm without need for any cleanup or concentration steps.

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