Hexane extraction

Fig. 4. Schematic outline for processing soybeans into oil and meal by hexane extraction. Courtesy of Dravo Corporation.

Carrot oil—The Hquid or the soHd portion of the mixture, or the mixture itself obtained by the hexane extraction of edible carrots (Daucus carota L.) with subsequent removal of the hexane by vacuum distillation. The resultant mixture of soHd and Hquid extractives consists chiefly of oils, fats, waxes, and carotenoids naturally occurring in carrots. 

Com endosperm oil—A reddish brown Hquid composed chiefly of glycerides, fatty acids, sitosterols, and carotenoid pigments obtained by isopropyl alcohol and hexane extraction from the gluten fraction of yellow com grain. 

Interaction of formaldehyde with 2,4-dinitrophenylhydrazine in acid media causes 2,4-dinitrophenylhydrazone (DNPhydrazone) formaldehyde formation. Gas-chromatographic analysis of 2,4-DNP-hydrazone formaldehyde toluene extract with an electron holding detector makes it possible to detect it at the level of 0,001 mg/dm. Phenol is detected in the form of tribromphenol yield, the hexane extract of which undergoes chromatography with an electron holding detector which provides the level of phenol detection of 0.001 mg/dm (the limit of quantitative detection). 

In a 500-ml. round-bottomed flask fitted with a reflux condenser are placed 16.2 g. (0.08 mole) of dry a-naphthylthiourea (Note 1) and 180 ml. of redistilled chlorobenzene. The flask is heated at the reflux temperature by means of an electric heating mantle. Evolution of ammonia begins almost at once, and all of the solid dissolves after 30-45 minutes. The solution is maintained at reflux for 8 hours (Note 2) and then evaporated on a steam bath at water-pump pressure to remove all of the chlorobenzene. The residue crystallizes on cooling and is extracted with four 30-ml. portions of boUing hexane (Note 3). Removal of solvent from the combined hexane extracts affords pale yellow crystals of naphthyl isothiocyanate, m.p. 58-59°. The yield is 12.7-13.0 g. (86-88%). Recrystallization from hexane (9 ml. of hexane for 1 g. of solute) gives colorless needles, melting point unchanged (Note 4). 

After the addition of 75 parts by volume of methanol and 150 parts by volume of acetic acid of 15% strength with adequate mixing, the solution is extracted with 2 portions each of 100 parts by volume of hexane. The combined hexane extracts are extracted with 15 parts by volume of acetic acid of 15% strength. The latter extract is added to the above acetic acid phase which is then extracted with 3 portions each of 75 parts by volume and 1 portion of 50 parts by volume of ethylene chloride. 

A. (S)-Ethyl 2-(t-Butyldimethylsilyloxy)propanoate (1). A 2-L, two-necked, round-bottomed flask equipped with a mechanical stirrer and inert gas inlet (Note 1) is charged with (S)-ethyl lactate (118 g, 1.0 mol), 500 mL of dimethylformamide (DMF), and imidazole (102 g, 1.5 mol) (Note 2). The solution is cooled in a ice bath and te/ t-butyldimethy 1 si 1 y 1 chloride (TBDMSC1) (150 g, 1.0 mol) is added in three 50-g portions, at intervals of 30 min between each addition. After the addition of the third portion, a white precipitate forms. The ice bath allowed to melt gradually overnight. After 18 hr, the reaction mixture is diluted with 300 mL of water and 500 mL of hexanes. The aqueous phase is separated and extracted with 300 mL of hexanes, and the combined hexane extracts are washed with three 50-mL portions of saturated brine, dried over MgS04, filtered, and concentrated by rotary evaporation to afford 240 g (103%) of the TBDMS ether as a colorless liquid. The product is distilled under vacuum (bp 70-78°C, 0.5 mm bath temperature 95-105°C) (Note 3) to afford 222 g (96%) of ester 1 as a colorless liquid (Notes 4, 5). 

Dale WE, Curley A, Cueto C. 1966. Hexane extractable chlorinated insecticides in human blood. Life Sci 5 47-54. 

A concentrated hexane extract (11.5 g/4 ml) of B. carterii resin and B. serrata resin, respectively, was applied to a column hlled with 80-g silica gel (Merck LiChroprep Si 60 No. 9390) conditioned by hexane. The fractionation was achieved by a gradient of 200-ml hexane followed by 200-ml hexane-dichloromethane (1 + 1 v/v), 200-ml dichloromethane and 200-ml dichloromethane-acetone (1+1 v/v) as eluents to give four subfractions of 200 ml each. These fractions were collected, concentrated, and applied to a TLC plate for a screening with the mobile phase dichlormethane-diisopropylether (9+1 v/v). 

FIGURE 16.9 An overview of the marker substances of (A) B. carterii and (B) B. serrata. (A) Lane 1 incensole (compound 3), lane 2 and 3 hexane extract of B. carterii, lane 4 incensole acetate (compound 2), lane 5 verticilla-4(20),7,ll-triene (compound 1). (B) Lane 1 m-camphorene (compound 4) and p-camphorene (compound 5), lane 2 cembrenol (compound 6), lane 3 Hexane extract of B. serrata. 

A homogenized sample of cereals, vegetables, fruits or potatoes (10-20 g) is extracted with an organic solvent such as acetone and methanol. After filtration, the extract is concentrated to about 20 mL by rotary evaporation below 40 °C. The residue is transferred with 5% sodium chloride (NaCl) aqueous solution and partitioned twice with n-hexane. The n-hexane extracts are dried with anhydrous sodium sulfate and subjected to a Florisil column chromatographic cleanup procedure. The eluate from the Horisil column is concentrated to dryness and the residue is dissolved in an appropriate amount of acetone for analysis by GC/NPD. ... 

Transfer the concentrate from Section 6.1 to a 200-mL separatory funnel with 50 mL of water and add 10 mL of saturated aqueous sodium chloride solution. Extract twice with 100 mL of n-hexane. Dry the n-hexane extract by passing through about 80 g of anhydrous sodium sulfate on a glass funnel into a 500-mL separatory funnel for the rice samples and into a 500-mL round-bottom flask for the soil sample. Wash the anhydrous sodium sulfate with 30 mL of n-hexane and combine the washings into the vessel. The n-hexane extract of soil sample is evaporated to dryness under reduced pressure, then the soil residue is processed as described in Section 6.3.2. 

For soil samples, sufficient sample cleanup could be conducted even if the alumina column was changed to a Sep-Pak Alumina N cartridge (Waters) by the following process. The entire sample of the dried n-hexane extract (Section 6.2) is introduced into a Sep-Pak Alumina N cartridge, and the column is washed with 50 mL of n-hexane. Subsequently, pyriminobac-methyl is eluted with 3 mL of ethyl acetate, the solvent is evaporate to dryness under reduced pressure and the residue is dissolved in an appropriate volume of acetone for GC analysis. 

Kennedy et al. developed a lasalocid immunoassay for application to residues in chicken meat and liver samples. The antibody was specific and did not cross-react with salinomycin, maduramicin, or monensin. Sample preparation consisted of homogenization in aqueous acetonitrile, removal of fat from an aliquot of the aqueous acetonitrile by hexane extraction, and evaporation of acetonitrile. The sample was then reconstituted with assay buffer. Liver required an additional solid phase extraction step. The LOQ was 0.02 xgkg for muscle and 0.15 agkg for liver. These workers were able to use the system to determine the half-life of lasalocid in the tissues. 

Transfer the concentrate into a 200-mL separatory funnel using two portions of 20 mL of n-hexane. Add 100 mL of saturated sodium chloride aqueous solution and extract twice with 100 mL of n-hexane by shaking for 5 min and allow the phases to separate. After dehydration of the n-hexane extract with 10 g of anhydrous sodium sulfate, concentrate the extract to dryness below 40 °C with a rotary evaporator. Transfer the residue with three portions of 5 mL of n-hexane into a glass column containing 10 g of Florisil (deactivated by water at a rate of 1%). Elute with 100 mL of n-hexane-ethyl acetate (9 1, v/v) and then with 100 mL of n-hexane-ethyl acetate (7 3, v/v). Concentrate the second eluate to dryness and dissolve the residue in 10 mL of n-hexane and analysis by gas chromatography/flame thermionic detection (GC/FTD). 

Transfer the sample extract (from Section 6.1) into a 300-mL separatory funnel, add 50 mL of water and extract the sample with 50 mL of n-hexane three times. Separate and dry the n-hexane layer with anhydrous sodium sulfate (plug the funnel with absorbent cotton and 50 g of anhydrous sodium sulfate), and collect the dried extract in a 300-mL of separatory funnel. Add 50 mL of acetonitrile to the separatory funnel and mix well for partitioning with the n-hexane extract three times. Collect the... 

To 100-gram batches of 1-day-old samples of cow s urine were added 0.05, 0.1, and 0.5 mg. of Compound 118 in acetone to give 0.5, 1.0, and 5.0 p.p.m., respectively. The urines were then extracted with two 50-ml. batches of hexane. Occasional emulsions were broken by centrifuging. The hexane extracts were dried with anhydrous sodium sulfate, filtered, evaporatively concentrated, and analyzed for Compound 118 as described under Procedure. The results of these analyses are shown in Table IV. Similar experiments with human urine gave slightly better recoveries. 

Table II shows data obtained by sequential hexanes and ethanol extractions of the desilylated networks. Attempts to extract the networks prior to desilylation failed because the samples swelled to such a great degree that they lost their mechanical integrity and disintegrated. The amount of hexanes extractable material is less than 3% in all cases which indicates high copolymerization yields. Ethanol extractables were not determined because the presence of the byproducts of the desilylation, which are in the ethanol, would have given artificially high readings.

Fish Polytron (methanol) or ball mill (hexane) extraction clean-up by GPC and alumina column chromatography GC/NPD 0.01 pg/g 79-97 Muiret al. 1981... 

The extraction of the AOT samples consisted of taking a 50-mL subsample and extracting by separatory funnel with hexane and 10% NaCl in water. The cleaned-up and dried hexane extract was then injected onto a gas chromatograph (GC) with an ECD (electron conductivity detector). The minimum quantifiable limit (MQL), or limit of quantification, for the method was 0.002 ug/mL dislodging solution. A typical set of chromatograms can be seen in Figures 1 and 2. 

Hwang and Bowen (2005b) Tomato paste hexane extract Apoptosis by Annexin V binding... 

The solution is cooled to room temperature and is washed with a few milliliters of benzene into a single-necked flask. The solvent is removed with a rotary evaporator connected to a water aspirator vacuum gentle heat is supplied from a steam bath. The residue is cooled to room temperature before air is admitted. About 200 ml. of hexane is added and stirred with the residue to extract most of the carborane. The brownish tar which remains undissolved is allowed to settle and the solution is decanted. A second extraction of the tar with 40 ml. of hexane converts the residue to a solid which is removed by filtration. The solid is washed on the filter with an additional 40 ml. of hexane. The combined hexane extracts are filtered and then washed in a separatory funnel with four 100-ml. portions of a chilled aqueous 10% sodium hydroxide solution, followed by four 100-ml. portions of water. After the yellow hexane solution has been dried over anhydrous magnesium sulfate and filtered, the solvent is removed by use of a rotary evaporator connected to a water aspirator. The carborane is washed with a small amount of pentane into a 300-ml. single-necked flask which is attached to an alembic column as pictured in Fig. 13. 

We have used the Kupchan scheme successfully in the separation of the multifunctional diterpenoid kalihinols from various Acanthella species (cf. Sect. 4.2.2). These compounds were distributed between the carbon tetrachloride and chloroform layers [19, 25], No isocyanosesquiterpenes were present in the hexane layer. By contrast, separate experiments with the Australian A. klethra revealed that sesquiterpenoid isonitriles were found exclusively in the hexane extract. No kalihinols were present in the carbon tetrachloride or chloroform extracts [26],... 

The 10,11-epoxide of chlorovulone I (107) was also obtained in low yield (0.05%) from the hexane extract of C. viridis [124], Its structure was assembled from spectroscopic data which showed a high degree of similarity to that obtained for chlorovulone I (100) except for UV and 1H NMR features due to the Cl0,11-olefin. Confirmation of structure came from synthesis of 107 by epoxidation of chlorovulone I. Epoxy-chlorovulone I (107) was found to possess the same 12R hydroxyl stereochemistry. The cis relationship of the epoxide and hydroxyl group was indicated by an intramolecular hydrogen bond as revealed by characteristic IR absorptions at high dilution. This 10,11-epoxide derivative... 

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