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At least 19 recordsLinked to original sources
PubMed1978

Separation of estrogen conjugates by high pressure liquid chromatography.

High pressure liquid chromatography using a prepacked commercial strong anion exchanger column (mu Partisil 10 SAX, 25 cm x 4.6 mm) was used to separate a mixture of eight estrogen conjugates. Chromatographic conditions using a 0.01 M potassium phosphate or 0.1 M NaCl as solvent in the isocratic mode are described for the separation of estrone glucosiduronate, 17beta-estradiol-3-glucosiduronate, 17beta-estradiol-17-glucosiduronate, estriol-3-glucosiduronate, estriol-16alpha-glucosiduronate, estriol-17-glucosiduronate, estrone sulfate and 17beta-estradiol-3-sulfate. This system gives high resolution of the estrogen conjugates in small eluent volumes in less than 30 min. The advantages of this high pressure liquid chromatographic system over other methods of separation are discussed.

Chromatography, High Pressure Liquid↗
PubMed1978

Determination of zearalenone in cornflakes and other corn-based foods by thin layer chromatography, high pressure liquid chromatography, and gas-liquid chromatography/high resolution mass spectrometry.

A simple cleanup procedure based on pH adjustments was used to obtain extracts of corn foods. The method gave good recoveries of zearalenone determined by thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC). As little as 5 ng zearalenone was detected by TLC, using Fast Violet B Salt as the spray reagent; the lower limit of detection in cornflakes was about 20 microgram/kg. With HPLC on Spherisorb silica (5 micrometer) and detection by fluorescence at an excitation maximum of 310 nm as little as 5 microgram zearalenone/kg cornflakes could be determined. While the TLC method was also applicable to corn chips, cornmeal, popcorn, and frozen corn, an interference was observed in HPLC of the latter 3 products. This interference was separated from zearalenone by adding a second HPLC analytical column (Spherisorb ODS). Gas-liquid chromatography coupled with mass spectrometric single ion monitoring at high resolution, although of limited availability, was shown to be the most sensitive and selective method for determining zearalenone in corn foods. The natural occurrence of zearalenone in a sample of cornflakes (13-20 microgram/kg) was demonstrated by all 3 detection procedures.

Chromatography, Gas↗
PubMed1977

Quantitative determination of phenol by high-pressure liquid chromatography.

High-pressure liquid chromatography was used with a 5-micrometer silica gel column to quantitate the phenol in phenolated calamine lotion USP and a commercial antiseptic solution. This method requires less than 10 min/assay, and other compounds present in the products analyzed did not interfere.

Anti-Infective Agents, Local↗
PubMed1979

Quantitative determination of hexylresorcinol in commercial antiseptic solution by high-pressure liquid chromatography.

High-pressure liquid chromatography was used with a 5-micron silica gel column to quantitate hexylresorcinol in a commercial antiseptic solution following extraction with methylene chloride. This method shows linearity to at least 0.025% hexylresorcinol. A mobile phase consisting of 63% heptane, 34% chloroform, and 5% methanol was used with a UV detector (254 nm) and a flow of 3 ml/min. No interfering substances were observed.

Anti-Infective Agents, Local↗
PubMed1977

Detection of low-level carbadox residues in animal feeds by high pressure liquid chromatography.

The high pressure liquid chromatographic (HPLC) method is capable of detecting from 1 to 0.024 ppm methyl 3-(2-quinoxalinyl-methylene)carbazate-N1,N4-dioxide (carbadox). Carbadox is extracted from the feed with 2% NH4OH in acetone, passed through a liquid-liquid partition, subjected to HPLC, and detected by using a 365 nm detector. No feed materials or other active drug ingredients produced false positive results.

Animal Feed↗
PubMed1978

Benzoyl peroxide assay using high-pressure liquid chromatography.

A highly specific assay for benzoyl peroxide was developed using high-pressure liquid chromatography. A concentration curve was recorded from 0.1 to 3.0 microgram with a correlation coefficient of 0.9969. The standard deviation for 10 individual analyses of a benzoyl peroxide preparation was +/- 0.547 (1.80% RSD).

Benzaldehydes↗
PubMed1979

Quantitation of serum tobramycin concentration using high-pressure liquid chromatography.

A high-pressure liquid chromatography method for the quantitative determination of tobramycin in serum is described. The antibiotic was separated from serum by chromatography on a silica gel column. The adsorbed antibiotic was derivatized with o-phthalaldehyde, and then eluted with isopropanol. The derivatized tobramycin was separated by reverse-phase chromatography and quantitated by fluorometry. Serum concentrations as low as 0.5 microgram/ml could be accurately measured. A linear response for serum samples containing tobramycin ranging from 0 to 20 microgram/ml was obtained. Other antibiotics, including various aminoglycosides, did not interfere with the tobramycin assay. Comparison with a standard microbiologic assay gave a correlation coefficient of 0.99. This chemical assay is sensitive, precise, specific, and can be performed in 30 minutes.

Animals↗
PubMed1977

A nitrosamide-specific detector for use with high-pressure liquid chromatography.

A highly specific automated method for identification of nitrosamides has been developed for use in conjuction with reversed-phase high-pressure liquid chromatography. The method is based on the well-known Griess reagent, and is capable of sensitivities of 0.5 nmoles of injected nitrosamide in most cases. The method may be used for analysis of nitrite, nitrosamides, nitrosocarbamates, and alkylnitrites.

Alkylation↗
PubMed1977

Rapid analysis of cefazolin in serum by high-pressure liquid chromatography.

A high-pressure liquid chromatography (HPLC) method has been developed for the analysis of cefazolin in serum. Serum was deproteinized by the addition of 6% trichloroacetic acid and injected onto a reverse-phase column with a mobile phase of 10 to 15% methanol in 1% aqueous acetic acid. Cefazolin chromatographed without interference from ultraviolet-absorbing components of serum, with a retention time of 3.1 min. Standard curves comparing peak area with concentration prepared from dog or human sera were linear over a range of 1.6 to 200 mug/ml. Results from the HPLC assay were compared with microbiological assays (cylinder plate method) on both standard serum samples and sera from dogs and human subjects receiving intramuscular cefazolin. The HPLC method was somewhat more accurate in comparison with the microbiological assay performed on serum samples of known concentration. The comparison of results from an analysis of serum levels of dogs or human subjects receiving cefazolin indicated that the two methods would lead to identical conclusions concerning pharmacokinetics or the achievement of therapeutic serum levels. The HPLC assay method presents an alternative to conventional microbiological assays, with marked improvement in speed (30 min) and considerable potential for future development.

Animals↗
PubMed1979

Stability-indicating assay for mecillinam using high-pressure liquid chromatography.

A high-pressure liquid chromatographic method has been developed for use as a stability-indicating assay for mecillinam. Seven related compounds and at least one unknown degradation product are well separated and easily determined. The accuracy of the method is in good agreement with the published UV assay and the precision of a series of seven replicate determinations is +/- 1.0% R.S.D.

Amdinocillin↗
PubMed1977

Metoclopramide metabolism and determination by high-pressure liquid chromatography.

A high-pressure liquid chromatographic method suitable for determining plasma metoclopramide levels at normal (10-20 mg) doses is described. Eight metabolites as well as metclopramide were isolated and identified in rat, dog. and human urine. The only common metabolite in these species is 2-[(4-amino-5-chloro-2-methoxybenzoyl)-amino] acetic acid. N-Deethylation is a major pathway for metoclopramide metabolism in the lower animals but not in humans. Metoclopramide is excreted mainly unchanged or as its conjugates by humans.

Animals↗
PubMed1978

Simultaneous determination of niacin, niacinamide, pyridoxine, thiamine, and riboflavin in multivitamin blends by ion-pair high-pressure liquid chromatography.

A high-pressure liquid chromatographic procedure for the simultaneous determination of niacin, niacinamide, pyridoxine, thiamine, and riboflavin was developed and applied to the analysis of multivitamin blends for these water-soluble vitamins. Reversed-phase ion-pair chromatography, using sodium hexanesulfonate as the counterion, was employed. Analysis time is shortened considerably and precision is improved by the application of this analytical technique as compared to the current official methods of analysis. Involved sample pretreatment is not required.

Chromatography, High Pressure Liquid↗
PubMed1976

Determination and identification of polycyclic aromatic hydrocarbons in smoked and charcoal-broiled food products by high pressure liquid chromatography and gas chromatography.

A high pressure liquid chromatographic procedure has been developed and applied to the analysis of polycyclic aromatic hydrocarbons (PAH's) in 70 samples of smoked food products commercially available in Canada, and in 6 charcoal broiled meats. In some cases a gas-liquid chromatographic procedure was used as a confirmatory technique. In the commercial samples PAH's were detected in approx. 70% of the samples. Total PAH's ranged from 0-141 ppb and individual PAH's from 0-38 ppb. With the charcoal-broiled samples, total PAH's and individual PAH's ranged from 0-164 ppb and 0-60 ppb respectively. These levels are similar to those observed in other countries.

Canada↗
PubMed1978

Resolution of desmosterol, cholesterol, and other sterol intermediates by reverse-phase high-pressure liquid chromatography.

A highly efficient technique has been developed for the resolution of several sterols that are intermediates in the biosynthesis of cholesterol and that differ only by one carbon-carbon double bond or by one methyl group. The technique described utilizes reverse-phase high-pressue liquid chromatography on a micronBondapak-C18 column with acetonitrile as eluting solvent. This procedure is capable of measuring the enzymatic conversion of desmosterol to cholesterol. This chromatographic separation can be conducted by reverse-phase high-pressure liquid chromatography in approximately 10 min, whereas other procedures can require several days.

Animals↗
PubMed1979

The screening and quantitation of diazepam, flurazepam, chloridazepoxide, and their metabolites in blood and plasma by electron-capture gas chromatography and high pressure liquid chromatography.

A combined GLC-ECD and HPLC procedure has been developed for the analysis of the most commonly encountered benzodiazepine drugs and has been applied to both plasma and postmortem blood samples. There is no doubt that since their introduction the use of these sensitive analytical methods have resulted in an increase in the incidence of detection of these drugs in both clinical and forensic toxicology cases.

Chlordiazepoxide↗