Isopropanol-chloroform, extracting solvents

In the Croteau and Fogerson study, the triperpenic alcohols and sterols were derivatized into their trimethylsilyl ether derivatives using bis-trimethylsilylacetamide. The isopropanol-chloroform extract contained higher amounts of sterols and triteipenic alcohols such as p-sitosterol and amyrin compared to the SF extract. This could be due to the high polarity of the extracting liquid solvent as opposed to the supercritical fluid, and the increased volatility of the silylated sterols and triteipenic compounds relative to our fatty acid methyl esters, in addition to these compounds, the isopropanol-chloroform extract reported earlier also contained ursolic acid, a polar triteipenic acid, which was not extracted with pure CO2. 

Dispersive Liquid-Liquid Microextraction The aforementioned SDME method, although it significantly reduces solvent consumption, is not free from drawbacks such as low extraction efficiency and slowly reached equilibrium. In many cases, the extraction efficiency can be increased by using dispersive systems such as the emulsion of organic solvent in an aqueous sample. In dispersive liquid-liquid microextraction (DLLME), a mixture of two solvents (extraction solvent and disperser) is injected by syringe into an aqueous sample. The extraction solvent is a water-insoluble and nonpolar liquid such as toluene, chloroform, dichloro-methane, carbon tetrachloride, or carbon disulfide. A water-miscible, polar solvent, typically acetonitrile, acetone, isopropanol, or methanol, is used as disperser. The typical concentration of extractant in such a mixture is in the range 1-3 %. 

As mentioned earlier, the composition of cranbeny seed oil has been studied by Croteau and Fogerson. The extracting solvent used in their method was a sequence of isopropanol, isopropanol-chloroform, and chloroform with the result... 

The plant tissues are homogenized with a 100 fold excess (by weight) of isopropanoi. The mixture is filtered, the residue is re-extracted with fresh isopropanoi, and finally is shaken overnight with isopropanol-chloroform (1 1, v/v). The filtrates are then combined, most of the solvent Is removed on a rotary evaporator, and the Iipid residue is taken up in chioroform-methanoi (2 1, v/v) and is given a "Foich" wash as above."... 

The extraction of steroids from tissues normally requires a mixture of solvents (e.g., methanol, isopropanol, hexane, and chloroform). Studies have also shown that pregnanes have been successfully extracted from brain tissue when the brain samples are allowed to stand in 95% aqueous ethanol for 7 days at 4°C (Wang et al., 1997 Bixo et al., 1984). 

Lipids can be identified and quantified using thin-layer chromatography (TEC) and gas chromatography (GC) (Galliard, 1968). Extraction of lipids is achieved by homogenizing potato tubers with isopropanol in a blender, followed by a series of filtrations and extractions with chloroform-methanol (2 1). Chloroform is removed by rotary evaporation and the residue is redissolved in benzene-ethanol (4 1). This extract is passed through a DEAE-cellulose column, and the fractions collected are subjected to TEC on 250 p,m layers of silica gel G, using three solvent systems. Fatty acid methyl esters for GC analysis are prepared by transmethylation of the parent lipids, or by diazomethane treatment of the free fatty acids released by acid... 

Ortega extracted dried and milled leaves with hot chloroform. He isolated salvinorin from the green residue left over after evaporating the solvent with column chromatography. He used thin layer chromatography to test for salvinorin in the fractions, and found it in the sixth and seventh of thirteen. The TLC plates were developed with 10 per cent phosphomolybdic acid in isopropanol (ethyl acetate/hexane, 45 55, Rf=0.7). Crystallize from methanol, melting point 238-240°C. 

Figure D1.6.5 Sequential latroscan TLC-FID profiles of the lipid classes extracted from the dorsal white muscle of Atlantic salmon. I, II, and III represent partial chromatograms from the three-stage development of total lipids on aChromarod Sill. The solvent systems were (I) 80 14 1 0.2 (v/v/v/v) hexane/chloroform/isopropanol/formic acid for 55 min (II) acetone for 15 min and (III) 70 30 3 (v/v/v) chloroform/methanol/water for 60 min.

The Extrelut cleanup method is suitable for most foodstuffs, such as cheese, yogurt, and other samples that tend to form emulsions during extraction. The prepacked or refilled Extrelut column in a plastic tube consists of a wide-pore kieselgel column. A sample is homogenized in 0.5 N sulfuric acid, diluted with water, and applied onto the Extrelut column for at least 15 min. The absorbed preservatives are eluted with a chloroform - isopropanol (9 1) mixture, and the elu-ate is collected and evaporated carefully nearly to dryness. The last few milliliters of solvent are removed with a gentle flow of nitrogen to prevent substantial losses of BA and SA, which have relatively high vapor pressures. The residue is transferred with methanol into a 10-ml volumetric flask and diluted to volume with methanol. To speed up the dissolution, the use of an ultrasonic bath is recommended. The filtered extract is analyzed on a /zBondaPak Cl8 column, with a... 

The derivatives are extracted by adding 0.5 ml of hexane and shaking. An aliquot portion of the clear hexane layer is then spotted on to a TLC plate (silica gel) and eluted with solvents such as benzene-chloroform (1 1) or hexane-acetone (7 3). After separation, the plate is dried and sprayed until moist with 20% triethanolamine in isopropanol. The plate is dried and observed under UV light at long wavelength. The limit of detection is ca. 5 ng per spot. For HPLC, an aliquot portion of the hexane extract is injected into a system consisting of small-particle silica gel (7-18 fan) as stationary phase and hexane-chloroform (9 1) as the mobile phase. The limits of detection range from 1 to 5 ng per injection. 

Phenolic extraction of cell lysates is one of the oldest techniques in DNA preparation. Examples of these have been presented in Chapters 6 and 7. Single cells in suspension are lysed with a detergent, and a proteinase enzyme is used to break down the protein molecules. Non-nucleic acid components are then extracted into an organic (phenol-chloroform) solvent, leaving nucleic acids in the aqueous layer. Two volumes of isopropanol are added to the isolated aqueous phase to precipitate the high-molecular-weight nucleic acids as a white mass. These are then treated with DNase-free ribonuclease (RNase) to remove the RNA. This is followed by a second treatment with proteinase, phenol extraction, and isopropanol precipitation. After precipitation, the DNA is separated from the isopropanol by... 

The mixture 25 g theobromine, 38 ml 4 N sodium hydroxide, 60 ml isopropanol, and 17 g n-hexyl chloride were heated 24 hours to 100°C in autoclave. The solvent was removed and the residual alkaline solution was extracted with chloroform, water layer was acidified. Yield of l-hexyl-3,7-dimethylxanthine was 88% MP 82°-83°C. The product may be prepared from theobromine sodium. 20.2 g theobromine sodium, 20 n-hexyl bromide and 100 ml toluene were ground 10 hours at 100°C in a ball mill. After above written treatment 22.3 g (84.5%) 1-hexyltheobromine was prepared MP 84°C. 

The choice of the type of extraction technique, whether with chloroform-methanol or hexane-isopropanol, makes little difference in the total recovery of lipid. Removal of nonlipid contaminants can certainly be achieved with either of the aforementioned wash techniques. Thus the decision on the choice of the solvent for extraction rests solely with the investigator. 

In this technique, a hydrophobic polymer is dissolved in an organic solvent, such as chloroform, ethyl acetate, or methylene chloride and is emulsified in an aqueous phase containing a stabilizer (e.g., PVA). Just after formation of the nanoemulsion, the solvent diffuses to the external phase until saturation. The solvent molecules that reach the water-air interphase evaporate, which leads to continuous diffusion of the solvent molecules from the inner droplets of the emulsion to the external phase simultaneously, the precipitation of the polymer leads to the formation of nanospheres. The extraction of solvent from the nanodroplets to the external aqueous medium can be induced by adding an alcohol (e.g. isopropanol), thereby increasing the solubility of the organic solvent in the external phase. A purification step is required to assure the elimination of the surfactant in the preparation. This technique is most suitable for the encapsulation of lipophilic drugs, which can be dissolved in the polymer solution. 

To be able to determine heroin and Its metabolite 6-0-acetylmorphine, morphine and normorphine in human urine, Yeh and McQuinn106 made use of a fractionated extraction Heroin was extracted with chloroform at pH 4.5, 6-0-acetylmorphine and morphine with ethylene dichloride containing 30 isopropanol at pH 8.5 and normorphine at pH 10.4 with the same solvent. The extract was derivatized with trimethylsilylimidazole and chromatographed at 230°C... 

Zuidema et al.6 used Propyl-8 ( = dimethylformamide-dipropylacetal) for propylation of theophylline. Fluoranthene was used as an internal standard for the determination of theophylline in biological fluids. Extraction was obtained with chloroform-isopropanol (95 5) after acidifying the sample (1 ml) with hydrochloric acid. After evaporation of the solvent the residue was dissolved in 0.5 ml of a methanolic solution of the internal standard. The methanol was evaporated and the residue dissolved in 30 ul Propyl-8 and gas chromatographed on a packed column of 3 % OV-17 on Gas Chrom Q at a column temperature of 220°C... 

Perrier and Lear converted theophylline to its butyl derivative by means of tetrabutyl-anrnonium hydroxide and on-column alkylation in connection with a rapid extraction procedure. Samples of 100 yl plasma were extracted with chloroform-isopropanol (95 5) containing the internal standard, amobarbital. The solvent was evaporated and the residue dissolved in 1 ml toluene. With the aid of 10 yl of an aqueous solution of tetrabutylammonium hydroxide, theophylline and amobarbital were quantitatively extracted from the toluene, and by injection of an aliquot of this solution into the gas chromatograph, alkylation took place in the injector, and quantitation of theophylline in concentrations in 100 ul plasma was possible with a flame ionization detector, using a packed column with 3 OV-17 on Chromosorb G at 250°C. 

Upon collection, tissues are typically frozen in liquid nitrogen and then homogenized by grinding the frozen sample to a fine powder. Extraction of tissue components is most commonly performed using LLE. Polar compounds are extracted with polar solvents including methanol, ethanol, isopropanol, acetonitrile, water, or polar solvent mixtures, while nonpolar compounds are extracted with ethyl acetate or chloroform. Such an LLE yields two fractions (polar and nonpolar) that can be analyzed separately [76,95,96],... 

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