Extraction digestion time

Figure 5. Influence of digestion time and temperature on extraction yield. Coal = Beynon solvent = anthracene oil coal solvent ratio = 1 4.

Figure 6. Influence of digestion time on the extraction yield and yield of filter cake. Digestion Annesley coal/hydrogenated solvent prepared at 430°C (— —), yield of filter cake (------------------), extraction yield.

Benzenesulphohydroxamic Acid.1—Hydroxylamine hydrochloride (10 g.) is boiled under reflux condenser with just enough methyl alcohol to dissolve it, and when still hot is decomposed by a solution of 3 g. of sodium in 60 c.c. of ethyl alcohol, which should not be added too quickly. After the mixture has been cooled, precipitated sodium chloride is removed at the pump and 8-5 g. of benzenesulphonyl chloride are then added in small portions to the solution of free hydroxylamine. Most of the alcohol is now removed by distillation from the water bath, the hydroxylamine hydrochloride which has separated is removed by filtration, and the filtrate is evaporated to dryness in vacuo at a moderate temperature. The residue is extracted three times with 15 c.c. portions of boiling absolute ether. Evaporation of the combined ethereal extracts in an open dish yields the benzene sulphohydroxamic acid in the form of a mass of crystalline plates which are digested with cold chloroform and filtered with suction. Yield 5-6 g. Melting point 126°. 

In a typical experiment the heat-killed ligation mixture is adjusted, by the addition of further Tris HC1, NaCl and MgCl2, to the correct ionic conditions and pH for EcoRI digestion, 10-30 units of jEcoRI added and the mixture incubated for 3h at 37°C. Excess EDTA (pH 8.0) is added and the mixture extracted with aqueous phenol. The aqueous phase is removed, the phenol layer washed once with water, and the combined aqueous solutions extracted five times with 1 ml ether to remove phenol. Residual ether is evaporated off in a stream of air. 

Phenol extract digested plasmid DNAs two times and ethanol precipitate. 

After the plant matter was rinsed with hexane as described above, the plants were spiked with 20 uL of 240 pg/uL C-TCDD. Each sample was digested in 50 mL of 50 percent (v/v) H SO and shaken for 15 min. The resulting solution was extracted three times with 50 mL portions of hexane. The hexane was removed from the H2S0 sample solution by centrifuging at 3000 RPM for 30 to 60 minutes after each hexane extraction. The hexane extractions were then pooled and taken through the cleanup procedure described below. 

Bubble nitrogen through the extracted digestate until the residual traces of hexane are removed. Do not allow nitrogen to bubble through the digestate for an extended time after the hexane has evaporated. 

G. D. Fulford, Use of Conductivity Techniques to Follow AI2O2 Extraction at Short Digestion Times, in Light Metals Bohner,... 

Liquid-phase reductive extraction with zinc chloride in an acid medium was tested to extract K vitamers as acetonitrile soluble hydroquinones from dairy products [125,126]. Acid hydrolysis [125] proved advantageous in isolating long chain menaquinones from cheese, provided the digestion time (10 min) was short. Semipreparative LC [125,127,128] and SPE [126] have sometimes been employed as a cleanup and concentration step after solvent extraction. Matrix solid-phase dispersion (MSPD) followed by PLE wifh ethyl acetate at 50°C and 1500 psi [129] and SEE using carbon dioxide at 8000 psi and 60°C [130] are fast, alternative procedures for exfracfing phylloquinone. 

Urea Enzymatic Dialysis Method. This method (16) uses 8 M urea [57-13-6] to gelatinize and facUitate removal of starch and promote extraction of the soluble fiber at mild (50°C) temperatures. EoUowing digestion with heat-stable a-amylase and protease, IDE is isolated by filtration or I DE is obtained after ethanol precipitation. Values for I DE are comparable to those obtained by the methods described eadier, and this method is less time-consuming than are the two AO AC-approved methods. Corrections for protein are required as in the AO AC methods. 

On digestion of this solid mass with 1 1. of ice and water, the sodium salt of the enol dissolves in the water, and the unreacted ester is removed by extracting the aqueous layer with two 200-ml. portions of ether (Note 5). The foimyl derivative settles out as an oil upon acidification of the aqueous layer with dilute sulfuric acid. The oil is extracted with three 200-ml. portions of ether, and the ethereal extract is washed several times with water and dried over anhydrous sodium sulfate. The ether is distilled, and, to remove traces of ethyl formate, the oil is heated on a steam bath under a pressure of 20-30 mm. for 1 hour. The remaining yellow formyl derivative weighs 27-29 g. (Note 6). 

Dried or freeze dried samples can be extracted with water-immiscible solvents such as EtOAc or diethyl ether. For quantitative extraction, dried samples are preferably rehydrated at different times for example, 5 to 10 min for dried mangoes, 30 min for lyophihzed red peppers and pasta. Rehydration is followed by extraction with acetone or MeOH. Bixin and norbixin from a mix dry powder of annatto and com can quantitatively be extracted with MeOH followed by acetone. In order to improve pigment recovery, extruded foods require pre-digestion with enzymes to liberate the pigment from the matrix. ... 

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