Chloroform-diethyl Ether Research Articles

Mineralization of .alpha.-, .gamma.-, and .beta.-Isomers of Hexachlorocyclohexane by a Soil Bacterium under Aerobic Conditions

The degradation of uniformly 14 C-labeled isomers (α, γ, and β) of hexachlorocyclohexane (HCH), added separately to a mineral salts medium as a sole source of carbon, by a soil bacterium, Pseudomonas sp., under aerobic conditions was studied. During aerobic degradation, about 10-12% of the 14 C in α- and γ-HCH was accounted for as 14 CO 2 as compared to 5% from β-HCH. Most of the 14 C in α- and γ-HCH accumulated as water-soluble products, while formation of water-soluble products from β-HCH was negligible. Almost all of the 14 C in the three isomers of HCH was accounted for in different fractions (CO 2 , chloroform-diethyl ether, water phase) following bacterial degradation under aerobic conditions. GC-MS analysis of β-HCH residues in the chloroformdiethyl ether extract suggested the formation of pentachlorocyclohexanol and tetrachlorocyclohexanediol as products of aerobic metabolism of β-HCH

HPLC method for rapid determination of acetylator phenotype by measuring urinary caffeine metabolites

A validated reversed-phase high-performance liquid chromatographic (RP-HPLC) method is developed for the selective and rapid determination of two major metabolites of caffeine, namely 5-acetylamino-6-formylamino-3-methyluracil (AFMU) and 1-methylxanthine (MX) from human urine. HPLC separation is achieved by means of a Supersphere-60 RP-Select B (4 μm) analytical column using a non-linear gradient elution programme of 70–95% solvent B (2.5% acetic acid—methanol, 60:40, v/v) in solvent A (water-acetonitrile, 80:20, v/v). A selective UV detection method is used for determination of AFMU, MX and internal standard with readings at 284, 268 and 248 nm, respectively. Urine samples are prepared for measurement by a simple chloroform—diethyl ether (80:20, v/v) extraction. The assay is validated with respect to linearity, sensitivity, accuracy, precision and system suitability. All validation parameters are found to be within the required limits. The limit of detection of AFMU and MX is found to be 50 ng/200 μl urine. Calibration curves show good linearity between 0.1 and 5 μg/200 μl urine concentration range for both metabolites. The assay is sufficiently sensitive and rapid (4.5 min chromatographic run) to be applied for routine monitoring of change in AFMU/MX molar ratio, indicating acetylation phenotype and change of caffeine metabolism in clinical cocktail studies.

A rapid, isocratic method for phospholipid separation by high-performance liquid chromatography.

A rapid, isocratic method for separating the most prevalent phospholipids by high-performance liquid chromatography is described. Baseline resolution of phosphatidylinositol, phosphatidylserine, phosphatidylethanolamine, phosphatidylcholine, lysophosphatidylcholine, and sphingomyelin is achieved in less than 40 min on a silica column. Lipids are injected in 10 microliter of chloroform-diethyl ether 1:2 (v/v) and eluted with a solvent mixture of acetonitrile-methanol-sulfuric acid 100:3:0.05 (v/v/v) at a flow rate of 1 ml/min. Neutral lipids and cardiolipin elute with the solvent front. Chromatography of a radioactive cell lipid extract indicates a recovery of better than 97%. The procedure is sensitive enough to permit the analysis of the main phospholipids present in a monolayer culture containing about 100 micrograms of cell protein.

Deacetylation of 4-(5-acetylamino-2-furyl)tiazole and formation of 1-(4-thiazolyl)-3-cyano-1-propanone by rat liver tissues

The reductive metabolism of the rat carcinogen 4-(5-nitro-2furyl)thiazole (NFT) to 1-4-thiazolyl)-3-cyano-1-propanone (TCP) is reported. Formation of TCP from NFT involved furan ring fission. This could have occurred through involvement of either aminofuran or N-hydroxylaminofuran as precursors. To examine if 4-(5-amino-2-furyl)thiazole is a precursor for TCP, a stable model compound, 4-(5-acetylamino-2-furyl)thiazole (AAFT), was prepared and subjected to enzymatic deacetylation, using rat liver tissue homogenates. AAFT was synthesized by catalytic hydrogenation of NFT with 5% palladium on activated carbon, followed by acetylation with acetic anhydride. AAFT, a white crystalline powder, melted at 168–170°, had an extinction coefficient of 17.9 mM −1 cm −1 at 293 nm in ethyl acetate, and exhibited spectroscopic and mass spectral characteristics consistent with the assigned structure. Incubation with rat liver 10,000 g supernatant preparations resulted in the biotransformation of AAFT as evidenced by a decrease in absorption at 290 nm. Incubation of 14C-labeled AAFT followed by extraction with chloroform-diethyl ether (1:1) resulted in the recovery of a major portion (56%) of the radioactivity in the organic phase when the label was at the 2-position of the thiazole ring, while the major amount (82%) of radioactivity was recovered in the aqueous phase when the 1- 14C-acetyl group was labeled. The radioactivity from the aqueous phase was extractable into the organic phase following acidification to pH 1, an observation consistent with deacetylation. Furthermore, the deacetylation product exhibited a mass spectrum, and retention times in gas and high pressure liquid chromatography, similar to those of synthetic TCP. These data establish 4-(5-amino-2-furyl)thiazole, derived from AAFT by deacetylation, as a precursor for TCP.

Simultaneous determination of tolmetin and its metabolite in biological fluids by high-performance liquid chromatography

A highly sensitive and selective high-performance liquid chromatographic assay has been developed for the separation and quantitation of tolmetin and its major metabolite in human biological fluids, viz. plasma, urine and synovial fluid. Analysis of plasma and synovial fluid required only 0.5 ml of the sample. The sample was washed with diethyl ether and extracted with diethyl ether—chloroform (2:1). The extracted compounds were injected onto a reversed-phase column (RP-2) and absorbance was measured at 313 nm. The standard curves in plasma were found to be linear for both tolmetin and the metabolite at concentrations from 0.04 to 10.0 μg/ml. Urine samples (0.5 ml) were diluted (1:1) with methanol containing the internal standard and were directly injected onto the reversed-phase (RP-2) column. Standard curves of tolmetin and metabolite in urine were linear in the range 5–300 μg/ml. Serum and synovial fluid concentrations of tolmetin and its metabolite in patients receiving multiple doses of tolmetin sodium were determined using the assay procedure.

Méthode d'analyse par chromatographie liquide haute performance des formultions à base de mélanges d'acides phénoxycarboxyliques, de dicamba, d'ioxynil et de bromoxynil

High-performance liquid chromatography analysis of formulations of phenoxycarboxylic acids, dicamba, ioxynil and bromoxynil mixtures Eighteen mixed formulations of phenoxycarboxylic acids and other herbicides such as dicamba, ioxynil and bromoxynil have been analyzed by high-performance liquid chromatography using a r-μm Nucleosil 50 column. The concentration of acetic acid in the eluent hexane-acetic acid depends on the formulation to be analyzed and on the analysis time. The formulations are extracted with a chloroform-diethyl ether mixture, and 20 μ1 of the extract are injected onto the coloumn. The compounds are detected at 285 nm. The method is simple, rapid and the formulations are specificially analyzed without derivatization.

Associated Complex Formation in a Binary Solution and the Concentration Fluctuation: The Chloroform–Diethyl Ether System

Abstract The relations between the associated complex formation and the concentration fluctuation in a binary solution were derived. The concentration fluctuation of a chloroform–diethyl ether system was determined by observing light-scattering spectra at various concentrations. The theoretical values of the concentration fluctuation of this system were calculated from the proposed relation by the use of the shape and the number population of the associated complex, as determined from the infrared absorption intensity measurements. The observed and calculated concentration fluctuations agreed quite well.

Diffusivities and densities for binary liquid mixtures

Accurate experimental liquid-diffusion coefficients are of considerable use in checking various theories of the liquid state, as well as for studies on the mechanism of mass transfer. In addition, a knowledge of liquid- diffusion coefficients will increase the understanding of transport processes in liquids. Diffusion coefficients for ideal and nonideal binary liquids mixtures were measured in the laboratory to develop a theory to predict transport properties of the liquid state. Liquid diffusivities were measured in ideal and nonideal systems covering the entire concentration range. The systems studied were benzene-chloroform, cyclohexane-carbon tetrachloride, cyclohexane-toluene, benzene-n-heptane, all at 25/sup 0/, 40/sup 0/, and 55/sup 0/C, respectively; benzene-cyclohexane at 25/sup 0/, 40/sup 0/, and 60/sup 0/C; benzene-toluene at 20/sup 0/ and 40/sup 0/C; and diethyl ether-chloroform at 25/sup 0/C. (14 refs.)

Determination of liquid‐mixture solubility parameters and interaction energy densities

AbstractIntegral, isothermal heat‐of‐condensation values for continuously generated vapors of various constant‐composition mixtures, along with the isothermal densities of the condensates, enable the calculation of the cohesive energy densities of solutions. Data for the complete range of composition of the chloroform‐acetone system and for a major portion of the chloroformdiethyl ether system at 35°C are reported. From these data, the specificinteraction‐energy density for each system is calculated, based upon an extension of the Scatchard‐Hildebrand Regular Solution Theory.The essential equality of the specific‐interaction energy‐density values for the two systems indicates a preponderance of the same kind of hydrogen bonding (CH‐‐‐O) in each.

Mischungswärmen und Verbindungsbildung in binären flüssigen Systemen I. Einstufen-Gleichgewochtsmodelle

The relationship between heats of mixing and chemical interactions has been investigated and is now discussed for three liquid binary systems, i. e. diethyl ether-chloroform, nitromethane-sulfuric acid, and isopropanol-isopropylamine. On the basis of a suitable equilibrium model, involving the formation of only one species of intermolecular compounds, equations HM= ƒ (N0 Δ) (HM=heat of mixing, N0 Δ =mole fraction of component A) are derived. The equations are convenient for representing the experimental data of symmetrical mixing curves, and they also allow us to calculate the thermodynamic quantities of the pertaining equilibrium reactions. Plotting HM versus N0 Δ/ (—HM) should give a straight line over the whole concentration range, thus warranting a reliable criterion for the applicability of the equilibrium model. The heats of mixing were measured at 25° and 20°, respectively, using a new type of continuous dilution calorimeter, which supplied a sufficient number of accurate experimental data.

Preliminary thin-layer chromatographic characterization of the rat harderian gland lipid

The lipid of the Harderian gland, which incorporates a considerable proportion of I- 14C-labelled acetate which had been injected into rats (and mice) could not be resolved from the main lipid fraction of the gland by TLC, either before or after saponification. The main lipid and acetate-incorporating fraction agrees in its chromatographic behaviour with the sterol ester band. About 83% of the radioactivity of the lipid extract from the Hardernia gland (24 h after the application of I- 14C-acetate) was found in this band. small amounts of free cholesterol were found in the Harderian gland extract. The cholesterol band was not appreciably labelled The main lipid of the unsaponifiable matter of the Harderian gland (about 99% of the radioactivity of this fraction 24 h after 14C-acetate injection) travels in hexane—ethyl acetate (80:20) and chloroform—diethyl ether—acetic acid at a rate slightly below that of dihydrolanosterol. On a AgNO 3-impregnated layer it is retarded, with respect to dihydroloanosterol, and more so than lanosterol. The unsaponifiable material gives a dull yellow colour and whitish yellow fluoroscence with the SbCl 3—acetic anhydride reagent.