Chloroform extraction with

Neutralise the cold contents of the flask with 500-600 ml. of 40 per cent, aqueous sodium hydroxide solution, equip the flask for steam distillation and steam distil until about 1 litre of distillate is collected. The steam distillate separates into two layers. Add solid sodium hydroxide (< 100 g.) to complete the separation of the two layers as far as possible. Remove the upper (organic) layer and extract the aqueous layer with three 50 ml. portions of chloroform. Dry the combined organic layer and chloroform extracts with anhydrous potassium carbonate and distil the mixture through a short fractionating column (e.g., an 8 Dufton column) after a fore run of chloroform, followed by pyridine, collect the crude 4-ethylpyridine at 150-166° (49 g.). Redistil through a Fenske-... 

Procedure. Dissolve a suitable weight of the sample of lead in 6M nitric acid add a little 50 per cent aqueous tartaric acid to clear the solution if antimony or tin is present. Cool, transfer to a separatory funnel, and dilute to about 25 mL. Add concentrated ammonia solution to the point where the slight precipitate will no longer dissolve on shaking, then adjust the pH to 1, using nitric acid or ammonia solution. Add 1 mL freshly prepared 1 per cent cupferron solution, mix, and extract with 5 mL chloroform. Separate the chloroform layer, and repeat the extraction twice with 1 mL portions of cupferron solution + 5 mL of chloroform. Wash the combined chloroform extracts with 5mL of water. Extract the bismuth from the chloroform by shaking with two 10 mL portions of 1M sulphuric acid. Run the sulphuric acid solution into a 25 mL graduated flask. Add 3 drops saturated sulphur dioxide solution and 4 mL of 20 per cent aqueous potassium iodide. Dilute to volume and measure the transmission at 460 nm. 

Urine Addition of sodium chloride, pH adjustment to 6, extraction with chloroform, extraction of chloroform extract with 3 N HCL addition of chloramine-T and extraction of colored product into chloroform. Absorbance at 457 nm 1-2 ppb ( g/L) 68 (4.6% RSD) Roberts and Rossano 1982... 

Wash chloroform extract with water, sodium hydrogen carbonate, and again with water. Dry chloroform solution with anhydrous sodium sulfate, evaporate and isolate p-anomer by crystallization or perform flash chromatography to separate a- from p-anomer (see Note 6). 

Test on Urine for Large Amounts Make 20 ml of urine alkaline with dilute ammonia solution, exh act with an equal volume of chloroform, shake the chloroform extract with 3 ml of 10% sulphuric acid, and centrifuge. A blue fluorescence in die acid phase, more noticeable under ultraviolet light, suggests the presence of quinidine or quinine. 

Extractive separation of Pd. Acidify the sample solution with hydrochloric acid (to -0.2 M in HCl), add 2 ml of the H2Dm solution and 5 ml of 0.1 M EDTA, mix well, and allow to stand for 10 min. Extract the Pd(HDm)2 with two portions of CHCI3, shaking for 1 min. Wash the combined chloroform extracts with two portions of 0.2 M HCl, and evaporate the organic phase to dryness on a water-bath. Mineralize the residue by heating with a few drops of cone. H2SO4 and cone. HNO3. Expel the nitric acid, allow the residual solution to cool, dilute it with water, and heat it until it clears. 

Dissolve 0.1 g of amodiaquine hydrochloride in 10 ml of water and add 2 ml of 2 M sodium hydroxide. Extract with two 20 ml quantities of chloroform, wash the combined chloroform extracts with 5 ml of water, dry with anhydrous sodium sulphate and evaporate to dryness. Dissolve the residue in 2 ml of chloroform. The infrared absorption spectrum of the resulting solution is concordant with the reference spectrum of amodiaquine. 

In a 100-ml separating funnel treat the combined chloroform extracts with 10 ml of 1 % ammonium fluoride solution, 2 ml of potassium thiocyanate... 

ThC(Bl ). It Is expected that there will be some loss of lead In O.OIJ dlthlzone. The lead recovery can be improved by shaking the last chloroform extract with 0.01 N acid. A similar, separa-... 

Wash each chloroform extract with 100 ml 30% sodium chloride solution. 

Shake a portion of powdered tablets with excess alkali and extract with chloroform. Determine the aspirin in the aqueous residue as given under Tablets of Aspirin and Phenacetin. Wash the chloroform extracts with dilute acid, evaporate and weigh the phenacetin. Make the acid washings alkaline with ammonia, extract with chloroform, evaporate and weigh or titrate the codeine. 

To the percolate add 30 ml of N sulphuric acid, or sufficient to render the mixture faintly acid, shake well, allow to separate and run off the lower layer. Continue the extraction with 10-ml portions of 0-lN sulphuric acid until extraction of the alkaloids is complete, as shown by the iodine test. Wash the mixed acid solutions with about 10 ml of chloroform and run off the latter into a second separator containing 20 ml of 0 1 N sulphuric acid, shake, allow to separate and reject the chloroform. Repeat the washing of the liquid in the first separator with two further 5-ml quantities of chloroform, transfer each in turn to the second separator, wash with the same aqueous acid liquid, allow to separate and reject the chloroform layer as before. Transfer the acid liquid from the second separator to the first separator, make just alkaline with dilute ammonia solution and add 2 ml in excess shake with successive portions of chloroform until complete extraction of the alkaloids is effected, washing each chloroform extract with the same 20 ml of water contained in another separator. Remove the chloroform by distillation, add to the residue 2 ml of dehydrated ethanol, evaporate at a temperature not exceeding 60, and dry at a temperature below 60for thirty minutes. Dissolve the residue in 2 ml of neutral 95 per cent ethanol, warm until dissolved, add 20 ml of 0 02N sulphuric acid and 10 ml of water cool and titrate with 0-02N sodium hydroxide, using methyl red as indicator. 1 ml of 0-02N acid = 0-01291 g of the alkaloids of aconite calculated as aconitine. 

Transfer about 01 g, accurately weighed, to a separator, add 20 ml of water and 5 ml of 10 per cent sodium carbonate decahydrate solution. Extract by shaking with successive quantities, each of 25 ml, of chloroform until complete extraction of the procaine is effected, washing each chloroform extract with the same 5 ml of water. Transfer the mixed chloroform extracts to a second separator, add 20 ml of 0 01 N sulphuric acid, shake thoroughly, allow to separate, run off the chloroform layer into a third separator and w ash with 5 ml of water. Titrate the excess of sulphuric acid in the aqueous solution and washings with O OIN sodium hydroxide using methyl red as indicator. 1 ml 0 01 N sulphuric acid == 0 002363 g of procaine base, C13H20O2N2. 

To 10 ml of syrup in a separator add 1 to 2 g of citric acid dissolved in 20 ml of water, make alkaline and extract the alkaloids with repeated small quantities of chloroform. Wash the chloroform extracts with water. Transfer the aqueous solution and washings to a 100-ml graduated flask, acidify with sulphuric acid, volatilise the dissolved chloroform, cool and make up to 100 ml. Estimate the hypophosphite in 20 ml of this solution by the method of Boyer and Bauzil given above. 

To 50 ml add 50 ml of ether and extract with 15 ml of 0-5N sulphuric acid. Repeat the extraction with successive quantities, each of a mixture of 10 ml of 0-5N sulphuric acid and 5 ml of 95 per cent ethanol, until extraction is complete. Combine the extracts and wash with three successive 5 ml quantities of chloroform, washing each chloroform extract with the same 20 ml of 0 5N sulphuric acid. Discard the chloroform and make the combined acid extract and washings alkaline to litmus paper with dilute ammonia solution. Extract the alkaloids by shaking with successive quantities, each of 10 ml of chloroform. Combine the chloroform solutions and wash with 3 ml of water discard the washing. Filter the chloroform solution, wash the filter with chloroform and evaporate the combined filtrate and washings on a water-bath until about 2 ml remain. Add three successive quantities, each of 2 ml, of dry ethanol, evaporating to dryness on the water-bath after each addition, and dry the residue for one hour at 80°. Dissolve the residue in 2 ml of warm neutral 95 per cent ethanol, add 5 ml of 0-05N hydrochloric acid and 10 ml of water, cool, and titrate the excess acid with 0 05N sodium hydroxide using methyl red and methylene blue solution as indicator. 1 ml 0-05N 0 0169 g C gHs OgN. 

Dissolve the equivalent of one suppository in 20 ml chloroform. Extract with four portions each of 30 ml 01N hydrochloric acid, washing each extract separately with the same portion of 10 ml chloroform. Make the washed aqueous extracts up to 200 ml with 01N acid. Dilute an aliquot five times with 01N acid and continue by the usual nitroso-morphine colorimetric assay. 

Cohesive-end ligation of the restricted fragments to a linearized vector often suffers low efficiency due to the persistent association of polymerase molecules with the product DNA throughout the routine procedure of phenol-chloroform extraction with vortexing, ethanol precipitation, and drying. Because dNTPs can partially survive these same treatments, the DNA polymerase, which is present and active during the subsequent restriction enzyme digestion of the PCR product, can fill in the 3 -recessive termini. 

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