Methanol Eluate Research Articles

Hydrophobic chromatography with dynamically coated stationary phases : IV. Anionic surfactant effects on alumina

The effects of addition to aqueous methanolic eluents of two alkyl sulphate surfactants on the chromatographic properties of aluminium(III) oxide gels have been studied. It was found that the basic active sites on the alumina surface interacted with anionic surfactants in a fashion analogous to that previously observed with acidic active centres on silica and cationic surfactants.

Thermodynamics of functional groups in reversed-phase high performance liquid-solid chromatography

The behaviour of functional groups having differing physicochemical characteristics have been examined in reversed-phase high performance liquid-solid chromatography using aqueous methanolic eluents. The effects of temperature, mobile phase organic modifier concentration and stationary phase on extrathermodynamic group values have been determined. Results fit into the framework of solvophobic theory with extrapolated group parameters being related to other extrathermodynamic terms. Group values exhibit linear enthalpy-entropy compensation behaviour as examined using ΔH-ΔG coordinates. A unique relationship between solute retention and the enthalpy of transfer for all solutes and phase systems examined is exhibited, and the overall study indicates that attempts to relate chromatographic retention data to drug liquid-liquid distribution is thermodynamically valid.

Influence of temperature on the retention behaviour of members of homologous series in reversed-phase high-performance liquid chromatography

The capacity factors of C 6C 16 n-alkanols, C 6C 12 n-alkanal dinitrophenylhydrazones and C 6C 12 2- n-alkanone dinitrophenylhydrazones have been determined at various temperatures on MicroPak CH-10 and Nucleosil C-18 octadecyl reversed-phase packings with aqueous methanol eluents. Linear log k′ vs. C n log k′ vs. I/ T, −Δ H° vs. C n and log k′ vs. −Δ H° relationships have been obtained. Equations are presented that describe the capacity factors as functions of both temperature and carbon number. The compensation temperatures determined according to Melander et al. indicate that the retention mechanisms underlying these reversed-phase separations are identical.

The Simultaneous Assay of Naproxen and Salicylic Acid in Serum Using High Pressure Liquid Chromatography

Abstract A rapid, sensitive, reverse-phase high pressure liquid chromatographic assay was developed for the simultaneous determination of naproxen and salicylic acid. These compounds are extracted from serum and then separated on a reverse-phase column using an acidified methanol eluent. Utilization of a flow-through fluorescence detector in series with a variable wavelength micro-UV detector enhances the sensitivity of the assay. Application of the assay to therapeutic levels of the drugs in human serum is demonstrated.

Liquid chromatography separation of organic acidic compounds

The influence of ionic compounds added to an aqueous methanol eluent on the retention behaviour of sulphonic, carboxylic acids and of phenols is demonstrated. Absolute and relative retentions can be optimized by changing the water-methanol concentrations. The optimum conditions for the separation of technical important sulphonic and carboxylic acids (dye intermediates) are shown.

Determination of cortisol in human plasma by reversed-phase high-performance liquid chromatography.

A method is described for the measurement of cortisol in human plasma using 45% aqueous methanol eluent on a 120 mm x 4.5 mm I.D. Hypersil octadecylsilane column with UV detection at 239 nm after a simple dichloromethane extraction and evaporation with a prednisone internal standard. The sample preparation time and chromatography time are each about 15 min and linear correlations have been obtained with plasma samples assayed by the Mattingly fluorimetric technique and a commercial-kit competitive protein binding method. Concentration down to 30 nmol/l may be measured and the method can be used when fluorimetry is invalidated by interference, particularly from spironolactone.

Carcinogenic azo dyes. XI. Analysis of biliary and urinary metabolities of 3'-methyl-4-(methylamino)azobenzene in rat.

Metabolites of 3'-methyl-4-(methylamino) azobenzene (3'-Me-MAB) in the rat bile and urine were investigated by use of a tracer technique. 3H-3'-Me-MAB in cottonseed oil was administered orally by a stomach tube. The dye metabolites in the bile and urine collected during 24 hr after the administration were hydrolyzed with β-glucuronidase/arylsulfatase. The hydrolyzed metabolites were then extracted with chloroform or separated by chromatography on an Amberlite XAD-2 using methanol as solvent. The metabolites in the chloroform extract or methanol eluate were identified by the reverse isotope dilution analysis, after or before separation by thin-layer chromatography. The N-demethylated, aryl hydroxylated, and their azo-reduced products were detected in the bile, in addition to the products oxidized at the ring methyl group as the new metabolites of 3'-Me-MAB. On the other hand, the metabolites retaining the azo-linkage were hardly excreted in urine. Instead, 3-aminobenzoic acid, 3-amino-6-hydroxytoluene, and their N-acetylated products were major metabolites in urine. The present results indicate that the metabolism for 3'-Me-MAB in the rat involves oxidation at the ring methyl group. Effect of the ring methyl group on the carcinogenic action of aminoazo dyes is also discussed.

Quantification of 5-fluorouridine in human urine by capillary gas-liquid chromatography with a nitrogen-selective detector.

A method for the quantitative determination of 5-fluorouridine (I) in human urine is presented. The analysis involves the isolation of 5-fluorouridine and the internal standard, 5-chlorouridine (II), on immobilized phenylboronic acid; the extract is further purified by mini-column anion exchange chromatography. The resulting methanolic eluate is evaporated to dryness, the residue is dissolved in dimethyl sulfoxide and permethylated using potassium-t-butoxide and methyl iodide. The permethyl derivatives of the nucleosides are reextracted from the reaction mixture and analyzed by GLC on a glass capillary column coupled to a nitrogen-selective detector. Analytical recovery of 5-fluorouridine added to human urine in the 0--1 microgram/ml concentration range was 68 +/- 6% and a linear detector response was obtained up to 1 microgram/ml. The detection limit was found to be 10 ng/ml, using a 1-ml urine sample.

Analysis of biliary and urinary metabolites of 3'-methyl-4-(dimethylamino)azobenzene in rats.

Metabolites of 3'-methyl-4-(dimethylamino)azobenzene (3'-Me-DAB) in the rat bile and urine were investigated by the use of a tracer technique. 3H-3'-Me-DAB in cottonseed oil was administered orally by a stomach tube. The dye metabolites in the bile and urine collected during 24 hr after the administration were hydrolyzed with beta-glucuronidase/arylsulfatase. The hydrolyzed metabolites were then extracted with chloroform or separated by chromatography on Amberlite XAD-2 using methanol as a solvent. The metabolites in the chloroform or methanol eluates were identified by the reverse isotope dilution analysis, before or after separation by thin-layer chromatography. The N-demethylated, aryl hydroxylated, and their azo-reduced products were detected in the bile, in addition to the products oxidized at the ring methyl group as the new metabolites. On the other hand, the metabolites retaining the azo-linkage were scarcely detected in urine and instead 3-aminobenzoic acid, 3-amino-6-hydroxytoluene, and their N-acetylated products were major metabolites in urine. These results indicate that the metabolism of 3'-Me-DAB in the rat involves oxidation of the ring methyl group. Significance of the ring methyl group in the carcinogenic action of aminoazo dyes is also discussed.

The structure of edpetisidine

Continuing an investigation of the alkaloids of the epigeal part of Petil~um ed~d~ (Rgl.) Vved [i, 2], the mixture of bases from the pH 8 fraction was chromatographed on a column of silica gel. A benzene--methanol (9:1) eluate yielded the new alkaloid ed~etisidine with mp 257-259°C (acetone), [a] D-33.63 ° (c 1.87; methanol). C=TH~sNOs (I), M"429, IR spectrum of (I), lmax, cm-*: 3400 (OH), 2760 (trans-quinolizidine), 1670 (>C---C<).

Determination of N-Methyl-2-Pyrrolidone in Waste Water at the PPM Level

N-Methyl-2-pyrrolidone is concentrated by adsorption on XAD-2 resin from an aqueous NaCl solution and eluted with methanol. It is determined in the methanol eluate by gasliquid chromatography.

Retention behavior of alkyl bonded superficially porous silica in the separation of alkylbenzenes with high pressure liquid chromatography.

The number of methylene groups, log k'and solvent composition can be related mathematically to estimate elution conditions and resolution during chromatography on alkyl bonded silica columns. The slope for a plot of log k'vs. the number of methylene groups is practically identical for various types of benzene homologs and is a linear function of the composition of methanol in an aqueous methanol eluent.

Studies on cardiovascular drugs. 8. Metabolism of 1-tert-butylamino-3-(o-(tetrahydrofurfuryloxy)phenoxy)-2-propanol hydrochloride (Y-6124)

The urinary metabolites of 1-tert-butylamino-3-[o-(tetrahydrofurfuryloxy) phenoxy]-2-propanol hydrochloride (Y-6124) in rats were investigated by a radiochemical method, thin-layer chromatography (TLC), mass spectrometry, and column chromatography using Amberlite XAD-2 resin. When 3H-labeled Y-6124 was orally administered, 84% of 3H counts in the 24 hr urine was adsorbed by Amberlite XAD-2 resin, which was follwed by quantitative eluation with methanol. Two metabolites (I, II) were detected in the methanol eluate by TLC. These (I and II) were hydrolyzed with β-glucuronidase to the corresponding aglycones III and IV, respectively. Further, treatment of compound IV with acid afforded compound V, which was easily reverted to IV under an alkaline condition. Compound III, which was the aglycone of metabolite I, was discovered to be a monohydroxylated derivative of Y-6124 by mass spectrometry and color reactions. On the other hand, compound V, which was derived from the aglycone (IV) of metabolite II, was found to be a monohydroxylated derivative of 1-tert-butylamino-3-[o-(5-oxotetrahydrofurfuryloxy)-phenoxy]-2-propanol by the above mentioned methods. Therefore, compound IV, the aglycone of metabolite II, was considered to be a monohydroxylated derivative of 3-hydroxy-4-[o-3 (tert-butylamino-2-hydroxypropoxy) phenoxy] pentanoic acid.

A method of identifying narcotic analgesics in human urine after therapeutic doses

Alkaloids were separated from urine in 15 min with an Amberlite XAD-2 resin column, and the methanol eluate was chromatographed on 2 thin-layer silica gel glass microfiber sheets to establish a pattern of spots for each narcotic analgesic and its metabolites. Ten milliliters of urine applied to a column of Amberlite XAD-2 resin (1 × 6 cm) was flushed with an equal volume of water. The adsorbed drug and its metabolites were eluted with methanol nonselectively into the same fraction as some highly colored urinary pigments. The latter served as a guide to collect the alkaloid-containing fraction. Sixty microliters of the fraction were spotted on 2 Gelman SG sheets; these chromatograms were developed in 2 solvent systems: I ( n-butanol-acetic acid-water, 35:3:10) and IV (CHCl 3 saturated with ammonium hydroxide). The chromatograms were sprayed with iodoplatinate reagent, and unknowns were identified by matching their pattern of spots (drug and metabolites) with the pattern for urine standards run on the same chromatograms. From patients receiving no medication and others receiving therapeutic doses of narcotic analgesics 140 coded urine samples were collected. These unknowns were not decoded until after completion of the analysis. Six (out of the 7) control samples from untreated patients were correctly demonstrated to contain no alkaloids. The remaining 134 of the 140 samples were shown to be positive to iodoplatinate. Of these 134, 88 were identified correctly to be 27 meperidine, 29 codeine, 2 morphine, 1 levorphanol, 27 pentazocine, and 2 dihydromorphinone samples. In the remainder, 13 could not be assigned to a specific narcotic analgesic, and 33 were misidentified. Both these types of errors arose largely from paucity in number of alkaloid spots for matching with the urine standards. In spite of these shortcomings, the ease, speed, high sensitivity for detection and possibility for differential identification of narcotic analgesics make this method highly practical.

Extraction, Cleanup, and Gas Chromatographic Determination of BHA and BHT in Fats and Oils

Abstract In preparing samples for analysis of antioxidants in fats and oils, melted fat and/or oil is mixed with Celite, blended with acetonitrile, and the acetonitrile is extracted with mixed ethers. The mixed ethers are evaporated, and the oily residue is incorporated with alumina acid. The alumina mixture is placed in a chromatographic column and eluted with aqueous methanol, and the methanolic eluate is extracted into mixed ethers. The ether extract is clean enough for TLC as well as GLC determinations. Recoveries from tallow, lard, and corn oil spiked at 16.7 and 66.7 ppm with BHA and BHT ranged from 80 to 95% for BHA and 91 to 115% for BHT.

A method for the quantitative determination of β-aminoisobutyric acid in the human urine by paper electrophoresis

A method for the quantitative determination of β-aminoisobutyric acid in human urine is described. The methanolic eluate of the copper complex is measured colori-metrically. Values of excreted β-aminoisobutyric acid in the urine of 10 normal subjects were determined.

Toluene中毒時尿中馬尿酸の定量に関する研究

Hippuric acid excretion in the urine of workers after exposure to toluene, was assayed by Gaffney's method. The results obtained are as follows. (1) The determination of hhippuric acid in the urine was carried out by paperchromatography, spoting 0.1 ml of urine on the filter paper (40×40 cm) which was (developed in a solvent system: butanol, acetic acid, and water, (4: 1: 1). After drying, the color reaction was brought to completion, by spraying with 4 per cent solution of p-dimethylaminobenzaldehyde in acetic acid anhydride saturated with sodium acetate, and by heating in a drying oven for one minute at 135°C. The Rf value of hippuric acid contained in the urine was 0.8 coincided with that of pure hippuric acid. The absorption spectrum of the methanol eluate of the colored spot of the workers' urine corresponded also with that of pure hippuric acid. (2)The hippuric acid excretion in men administered orally with sodium benzoate showed the maximum value one hour later and ceased 4 hours after the administration. (3) In a plastic manufacturing factory using toluene as a solvent, a group of workers exposed to 50p.p.m. of toluene in the air excreted hippuric acid as much as 3.4 times the pre-exposure value, and in another group exposed to 20 p.p.m. it was 1.9 times. These results may indicate that excretion of hippuric acid in the urine is proportional to the concentration of toluene in the air. (4) At an autotricycle factory using the mixture of toluene and benzene (4:1), an increase of hippuric acid excretion in the urine of workers was recognized after exposure to this gas mixture.

A Method for Extracting and Purifying Streptomycin Suitable for Large-scale Production

SUMMARY: A method is described for extracting streptomycin from culture filtrates by adsorption on charcoal at pH 6-8, elution with 1·2% (v/v) aqueous phosphoric acid, readsorption of the eluate on charcoal at pH 7, elution with acidified methanol, followed by evaporation at reduced pressure and precipitation of streptomycin by dilution of the concentrated methanol eluate with 5 volumes acetone or amyl acetate. An indication is given of the order of recovery, and the potency of the product obtained. The stability of streptomycin under the conditions of pH and temperature to which it may be subjected during the extraction is outlined. The process has been carried out in pilot-scale production equipment handling 1500 1. batches of culture filtrate.