Hexane-diethyl ether

Organolithium reagents (Section 14 3) Lithi um metal reacts with organic halides to pro duce organolithium compounds The organic halide may be alkyl alkenyl or aryl Iodides react most and fluorides least readily bro mides are used most often Suitable solvents include hexane diethyl ether and tetrahy drofuran... 

A number of techniques have been developed for the trace analysis of siUcones in environmental samples. In these analyses, care must be taken to avoid contamination of the samples because of the ubiquitous presence of siUcones, particularly in a laboratory environment. Depending on the method of detection, interference from inorganic siUcate can also be problematic, hence nonsiUca-based vessels are often used in these deterrninations. SiUcones have been extracted from environmental samples with solvents such as hexane, diethyl ether, methyl isobutylketone, ethyl acetate, and tetrahydrofuran (THF)... 

Physalien (all trans /J-carotene-3,3 -diol dipalmitate) [144-67-2] M 1044, m 98.5-99.5°, A (Xmax) 1410 (449nm), 1255 (478nm) in hexane. Purified by chromatography on water-deactivated alumina, using hexane/diethyl ether (19 1) to develop the column. Crystd from benzene/EtOH. Stored in the dark, in inert atmosphere, at 0°. 

Aromatic hydrocarbons are generally nonpolar. They are not soluble in water, but they dissolve in organic solvents such as hexane, diethyl ether, and carbon tetrachloride. 

A solution of 2.5 g (45 mmol) of (Z)-2-butene, 40 mmol of butyllithium and 4.5 g (40 mmol) of /-BuOK in 30 mL of THF is kept for 15 h at — 50 °C. The solution is cooled to —75 C and 20 mL (88 mmol) of the 1 1 fluorodimethoxyboranc-dicthyl ether adduct are added, followed 1 h later by 44 mmol of benzaldc-hyde, The mixture is stirred at — 75 C for an additional hour and is then warmed to 25 C over 30 min and diluted with 100 mL of diethyl ether, washed with three 50-mL portions of NaCl and evaporated. The product is chromatographed on silica gel eluting with hexane/diethyl ether 4 1 and is further purified by distillation yield 40% d.r. (synjanti) 96 4. 

Flash column chromatography was performed using silica gel (6 cm diameter x 35 cm height), eluting with 19/1 hexane/diethyl ether. 

Mobile phase n-Hexane — diethyl ether — ethanol — ethyl acetate — formic acid (909+40+26+25+1)... 

Hexane — diethyl ether — 1-butanol — ethyl acetate (65 + 15+11+9). 

Mobile phase /i-Hexane — diethyl ether — glacial acetic acid (80-1-20-1-1). 

R-Hexane — diethyl ether - ethanol - ethyl acetate - formic acid (543-1-200-1-130+127-1-1). 

Hexane - diethyl ether - 1-butanol - ethyl acetai (65+15+11+9). 

The new lipid occurred only in the plasma hpids of newborns and was not present in membrane hpids of red cell membranes or platelets. Total lipids were extracted from plasma and from red blood cell membranes and platelets. A total lipid profile was obtained by a three-directional PLC using silica gel plates and was developed consecutively in the following solvent mixtures (1) chloroform-methanol-concen-trated ammonium hydroxide (65 25 5, v/v), (2) chloroform-acetone-methanol-ace-tic acid-water (50 20 10 15 5, v/v), and (3) hexane-diethyl ether-acetic acid (80 20 1, v/v). Each spot was scraped off the plate a known amount of methyl heptadecanoate was added, followed by methylation and analysis by GC/MS. The accmate characterization of the new lipid was realized using NMR technique. 

Although not very commonly used in the separation of nentral hpids, two-dimensional systems have been nsed to separate hydrocarbons, steryl esters, methyl esters, and mixed glycerides that move close to each other in one-dimensional systems. Complex neutral lipids of Biomphalaria glabrata have been first developed in hexane diethyl ether (80 20), dried, and the plates have been turned 90°, followed by the second development in hexane diethyl ether methanol (70 20 10) for complete separation of sterol and wax esters, triglycerides, free fatty acids, sterols, and monoglycerides [54]. 

The residue of the acetonitrile extract described above is dissolved in 5 mL of n-hexane and applied to a silica cartridge. Naproanilide and its metabolite are eluted with 10 mL of n-hexane-diethyl ether-acetic acid (85 15 1, v/v/v) after washing the cartridge with 5mL of n-hexane-diethyl ether-acetic acid (95 5 1, v/v/v). When using a Florisil column (10-g), naproanilide is eluted with 100 mL of diethyl ether-n-hexane (1 1, v/v) after washing the Florisil column with 100 mL of diethyl ether-n-hexane... 

Instead of an SPE Horisil cartridge, an SPE silica gel cartridge is also used. After pre-washing the SPE silica gel cartridge with 5 mL of n-hexane, the concentrated residue in the flask is dissolved in 8 mL of n-hexane, the solution is applied to the cartridge, and then the eluate with n-hexane is discarded. Pendimethalin is eluted with 8 mL of n-hexane-diethyl ether (7 3, v/v). 

Crooks et al. developed a monensin immunoassay for the detection of residues in broiler livers. Livers were homogenized in aqueous acetonitrile, subsequently extracted with sodium hydroxide followed with hexane-diethyl ether, and the remaining solvent was evaporated before reconstitution in buffer for analysis. The LOD (mean-I-3 SD) was 2.9qgkg and the LOQ (mean- -6SD) was 4.6p.gkg . Incurred samples showed considerable animal-to-animal variation, but all samples were below the detection limit after 3 days. 

Acetone, acetonitrile, n-hexane, diethyl ether, sodium chloride, anhydrous sodium sulfate reagent grade (Wako Pure Chemical Inc., Japan)... 

Transfer the sample to the column and drain the solvent to the top of the sodium sulfate layer. Rinse the round-bottom flask three times with 3-mL portions of hexane, adding these rinses sequentially to the column and draining the solvent to the top of the sodium sulfate layer before the next addition. Pass 90 mL of hexane through the column, followed by 50 mL of hexane-diethyl ether (15 1, v/v). Add each portion of eluting solvent to the round-bottom flask and sonicate the flask before adding the solution to the column. Discard the accumulated eluate. Place a 250-mL round-bottom flask under the column and elute the pyriproxyfen residues with 50 mL of hexane-diethyl ether (15 1, v/v), followed by 20 mL of hexane-acetone (7 3, v/v). As before, add each portion of eluting solvent to the round-bottom flask and sonicate the flask before adding the solution to the column. Rotary evaporate the combined eluate under reduced pressure in a <40 °C water-bath to 40-50 mL. Transfer the sample to a 100-mL round-bottom flask with three 5-mL acetone rinses, and continue rotary evaporation to take the sample just to dryness. Reconstitute the sample in 1.0 mL of toluene with sonication for analysis (Section 6.2). 

The variety of cleanup columns included may allow for rapid adaptation to additional matrices. If using hexane-diethyl ether (15 1, v/v) as an eluent, this solution should be prepared just prior to use. Cleanup with silica gel and hexane-ethyl acetate (4 1, v/v) is recommended for most crop samples. 

In the UV filter analyses, clear extracts were obtained which did not need any further time- and labor-consuming cleanup when using PLE with in-cell purification. In contrast, a thorough purification procedure was required for the cleanup of the extracts obtained by solid-liquid extraction. Columns packed with silica gel (previously activated) in hexane having Na2S04 at the top of the column were employed for the purification of the extracts. The two first fractions obtained with 20 mL of hexane and 20 mL of hexane/diethyl ether (9/1, v/v) were discarded and 4-MBC, EHMC, and OC were collected with 50 mL of hexane/diethyl ether (9/1, v/v). OT was recovered with 70 mL of hexane/diethyl ether (3/2, v/v). 

In solvents other than water such as hexane, diethyl ether, or liquid ammonia (b.p. -33 °C), bases stronger than hydroxide ion can be used. All of these solvents are very weak acids. 

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