Liquid-chromatographic determination of ethylene glycol in plasma.

1982 ◽  
Vol 28 (1) ◽  
pp. 32-33 ◽  
Author(s):  
R N Gupta ◽  
F Eng ◽  
M L Gupta
Keyword(s):  
Liquid Chromatography ◽  
Ethylene Glycol ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Standard Curve ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract In this novel procedure for determining ethylene glycol in plasma by liquid chromatography, benzoyl esters of ethylene glycol and of benzyl alcohol (used as the internal standard) are prepared directly in plasma. The benzoyl esters, highly ultraviolet-absorbing chromogens, are ideal compounds for analysis by reversed-phase liquid chromatography with methanol/water as the mobile phase. The benzoyl derivative of ethylene glycol is well separated from the derivative of the internal standard and from plasma constituents. The standard curve is linear to 400 mg of ethylene glycol per liter. As little as 10 mg of ethylene glycol per liter of plasma can be measured. Other commonly ingested alcohols do not interfere.

Liquid-chromatographic determination of nadolol in plasma.

1983 ◽  
Vol 29 (6) ◽  
pp. 1085-1087 ◽  
Author(s):  
R N Gupta ◽  
R B Haynes ◽  
A G Logan ◽  
L A Macdonald ◽  
R Pickersgill ◽  
...  
Keyword(s):  
Plasma Sample ◽  
Antihypertensive Drugs ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Standard Curve ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We describe a liquid-chromatographic procedure for determining nadolol in plasma. After an analog of nadolol is added as internal standard, the plasma sample is passed through a disposable BondElut C18 column. After several column washes, nadolol and the internal standard are eluted with methanol, and the eluate is evaporated and reconstituted with the mobile phase (acetonitrile/water, perchloric acid, and tetramethylammonium hydroxide). An aliquot of the extract is chromatographed on a non-silica resin-base reversed-phase column. The peaks are detected by fluorescence (lambda ex = 265 nm and lambda em = 305). Drug and internal standard are well resolved, and only a few extraneous peaks appear. The standard curve ranges from 10 to 400 micrograms/L. We are using this procedure to determine steady-state concentrations of nadolol in patients receiving various dosages of nadolol along with other types of antihypertensive drugs.

Determination of Sulfamethazine in Bovine and Porcine Tissues by Reversed-Phase Liquid Chromatography

1994 ◽  
Vol 77 (3) ◽  
pp. 558-564 ◽  
Author(s):  
Joe O K Boison ◽  
Lily J-Y Keng
Keyword(s):  
Internal Standard ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Dihydrogen Phosphate ◽  
Sodium Dihydrogen Phosphate ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Layer Chromatography

Abstract A simple, sensitive, and rapid method for the liquid chromatographic determination of sulfamethazine in animal tissues was developed by using sulfaethoxypyridazine as the internal standard. Homogenized tissue is extracted with chloroform, and the sulfa drugs are back-extracted from chloroform into alkaline sodium chloride solution. The pH of the aqueous extract is adjusted to 6, and the sulfas are concentrated on a conditioned C18 cartridge and eluted with 1 mL methanol. Sulfamethazine and sulfaethoxypyridazine are separated from tissue co-extractives by reversed-phase chromatography on a C18 column by using 0.05M sodium dihydrogen phosphate-methanol (7 + 3). Detection is performed at 265 nm. The method has a detection limit of 2 ng/g. Results obtained by this method were compared with those obtained by the official thin-layer chromatography/densitometric method.

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 Thiamine, Riboflavin, and Pyridoxine in Infant Formula

1992 ◽  
Vol 75 (3) ◽  
pp. 561-565 ◽  
Author(s):  
George W Chase ◽  
William O Landen ◽  
Ronald R Eitenmiller ◽  
Abdel-Gawad M Soliman
Keyword(s):  
Internal Standard ◽  
Ammonium Hydroxide ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Acid Sodium Salt ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract An Ion pairing reversed-phase liquid chromatographic method developed for multivitamin supplements and premlxes was applied to the simultaneous determination of thiamine, riboflavin, and pyridoxine In perchloric acid extracts of milkand soy-based Infant formulas. The method uses m-hydroxy benzoic acid as Internal standard and a mobile phase consisting of water, acetonltrile, hexanesulfonlc acid sodium salt, and ammonium hydroxide solution, adjusted to pH 3.6 with phosphoric acid. The column Is a 15 cm x 3.9 mm id Nova Pak C18. Limits of detection were 0.15 μg/mL for thiamine and 0.09 μg/mL for riboflavin by UV detection at 254 nm, and 0.010 μg/mL for pyridoxine by fluorescence detection. Mean percent recoveries based on triplicate determinations were 102 ± 1.8,102 ± 3.3, and 101 ± 3.1 for thiamine, riboflavin, and pyridoxine, respectively. The results compared favorably with the AOAC methods for thiamine, riboflavin, and pyridoxine.

Improved liquid-chromatographic determination of haloperidol in plasma.

1984 ◽  
Vol 30 (7) ◽  
pp. 1228-1230 ◽  
Author(s):  
A K Dhar ◽  
H Kutt
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Room Temperature ◽  
Internal Standard ◽  
Isoamyl Alcohol ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract This method for determination of haloperidol in plasma is based on "high-performance" isocratic liquid chromatography with the use of a C8 bonded reversed-phase column at room temperature. Haloperidol and the internal standard (chloro-substituted analog) are extracted from alkalinized plasma into isoamyl alcohol/heptane (1.5/98.5 by vol) and back-extracted into dilute H2SO4. The aqueous phase is directly injected onto the column. The mobile phase is a 30/45/25 (by vol) mixture of phosphate buffer (16.5 mmol/L, pH 7.0), acetonitrile, and methanol. Unlike other liquid-chromatographic procedures for haloperidol, commonly used psychotropic drugs do not interfere. Analysis can be completed within an hour. The procedure is extremely sensitive (1.0 microgram/L) and is well reproducible (CV 5.6% for a 2.5 micrograms/L concentration in plasma).

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.

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.

Improved liquid-chromatographic determination of 3-methoxy-4-hydroxyphenylethyleneglycol in urine with electrochemical detection.

1984 ◽  
Vol 30 (1) ◽  
pp. 140-143 ◽  
Author(s):  
J R Shipe ◽  
J Savory ◽  
M R Wills
Keyword(s):  
Mobile Phase ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Improved Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Mean Concentration ◽  
Phase Column

Abstract In this improved method for quantifying 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) in urine, after a multistep extraction of MHPG and internal standard (iso-MHPG) from 3.0 mL of urine, the compounds are separated on a C18 reversed-phase column and quantified by use of an electro-chemical detector. The isocratic chromatographic separation takes about 16 min. The mobile phase is phosphate buffer/acetonitrile (88/12 by vol), the flow rate 0.7 mL/min. Recycling the mobile phase and automating the sample injection make possible the unattended assay of more than 70 samples per day. The within-run precision of the method is excellent (CV 1.8%) at a mean concentration of 1.1 mg/L.

Gas-Liquid Chromatographic Determination of β-Asarone in Wines and Flavors

1976 ◽  
Vol 59 (3) ◽  
pp. 675-677
Author(s):  
Randolph H Dyer ◽  
Glenn E Martin ◽  
Peter C Buscemi
Keyword(s):  
Liquid Chromatography ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Ethyl Palmitate ◽  
Ultraviolet Spectra ◽  
Liquid Chromatographic Determination ◽  
Mass Spectrometery ◽  
Liquid Chromatographic

Abstract Wine samples containing β-asarone (cis-2,4,5-trimethoxy-1-propenylbenzene) are distilled; β-asarone is extracted by hexane and then quantitatively determined by gas-liquid chromatography (GLC), using ethyl palmitate as the internal standard. The GLC procedure is rapid and yields precise and accurate results. Mass spectrometery confirmed the identity of the GLC peak as β-asarone. The ultraviolet spectra of β-asarone and its isomer were also determined.

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