Precipitate transfer

In 1995, Nevissi and Strebin described a simple fluidic system to deliver sample and reagents to a TRU-Resin column for the separation of Pu and Am.79 A filter was included on-line to capture a precipitate containing the actinides dissolution of the precipitate transferred the sample onto the column downstream. Radionuclides were detected with a-spectrometry off-line. 

The reaction product is collected in filter tube C by pressurizing the reaction flask with nitrogen and allowing the pressure to force the slurry through stopcocks j and k into filter tube C. The solid chromium(II) diphenylphosphinate collects on the coarse glass frit, and the solution exits via stopcock l. In order to get as complete a transfer as possible, the reaction flask has to be tilted and swirled. The final precipitate transfer can be aided by a small amount of deaerated methanol, added via the dropping funnel. 

As an alternative to TCA precipitation, transfer 100 //I of the SI-digested preparation to a dry 2.4-cm Whatman DE-81 filter disk in a vial. Wash the disk twice with 5-ml volumes of 5% Na2HP04 and twice with 5-ml amounts of distilled water. Dry the filter and measure the radioactivity. 

Precipitation Transfer In cloud scavenging Dry deposition Precipitation... 

After cooling, the contents of the test tubes should be poured into a beaker of cold water (safety glasses ). The mixture is neutralised with milk of lime and the precipitate transferred to the coruainer used for storing less toxic inorganic salts. The solution is poured down the drain. 

The solid residue is stirred with an aqueous soda solution. The filtrate is poured down the drain and the precipitate transferred to the container used for collecting less toxic heavy metal salts. 

The reason for comparing solution reactions to surface reactions here is simple in both cases, an Fe —anion bond (or bonds) is formed. It is reasonable to expect that the bond energy should be about the same in solution and at the surface consequently, a tendency for anions to form ion pairs (or precipitate) transfers to a sim-... 

If you have no iron precipitate, transfer the solution to an electrolytic beaker. 

Fig. 51. Apparatus for precipitation in the absence of air. Arrangement for drying and transfer of the precipitates transfer vessel with adapter 7—storage vessel with sealing constriction 2-10—ground...

The sample beaker is removed from the water bath and allowed to stand undisturbed for a minimum of 3 hr. The supernatant solution is carefully aspirated off (avoid distiu bing precipitate) and the precipitate transferred to a 90-ml Pyrex centrifuge tube with a distilled water rinse. The precipitate is centrifuged for 5 min at 2000 rpm and the supernate carefully discarded. The sample beaker walls are then rinsed down with 4 N HCl from a wash bpttle and the rinse transferred to the 90-ml tube. The final volume in the tube should be approximately 50 ml. 

About 7-8 grammes of the sample are dissolved in water, and made up to 100 c.c., and the total alkalinity determined by titrating 20 c.c. with N/1 acid, using methyl orange as indicator. To another 20 c.c. is added barium chloride solution (10 per cent.) until it ceases to give a precipitate, the precipitate allowed to settle, and the clear supernatant liquid decanted off, the precipitate transferred to a filter paper and well washed, and the filtrate titrated with N/1 acid, using phenol-phthalein as indicator. The second titration gives the amount of caustic alkali present, and the difference between the two the proportion of carbonate. 

Actual Chloride, either titrated with N/10 silver nitrate solution, using neutral potassium chromate solution as indicator, or, preferably, estimated gravimetrically as silver chloride by precipitation with silver nitrate solution, the precipitate transferred to a tared filter paper, washed, dried and weighed. 

Transfer the quinoline chlorozincate to a beaker, add a small quantity of water, and then add 10% sodium hydroxide solution until the initial precipitate of zinc hydroxide completely redissolves, and the free quinoline separates. Transfer the mixture to a separating-funnel, wash out the beaker with ether, adding the washings also to the solution in the funnel, and then extract the quinoline twice with ether. Dry the united ethereal extracts by adding an ample quantity of powdered potassium hydroxide and... 

If no solid precipitate is obtained but the solution becomes cloudy, a low-melting or liquid phenol is indicated this will, of course, be revealed also by the characteristic phenolic odour. Transfer to a separating-funnel and extract with an equal volume of ether. Separate and dry with anhydrous sodium sulphate. Distil off the ether and identify the residue. 

Add 1 ml. of the alcohol-free ether to 0-1-0-15 g. of finely-powdered anhydrous zinc chloride and 0 5 g. of pure 3 5-dinitrobenzoyl chloride (Section 111,27,1) contained in a test-tube attach a small water condenser and reflux gently for 1 hour. Treat the reaction product with 10 ml. of 1-5N sodium carbonate solution, heat and stir the mixture for 1 minute upon a boiling water bath, allow to cool, and filter at the pump. Wash the precipitate with 5 ml. of 1 5N sodium carbonate solution and twice with 6 ml. of ether. Dry on a porous tile or upon a pad of filter paper. Transfer the crude ester to a test-tube and boil it with 10 ml. of chloroform or carbon tetrachloride filter the hot solution, if necessary. If the ester does not separate on cooling, evaporate to dryness on a water bath, and recrystallise the residue from 2-3 ml. of either of the above solvents. Determine the melting point of the resulting 3 5 dinitro benzoate (Section 111,27). 

Dissolve 200 g. of sodium nitrite in 400 ml. of water in a 2-litre beaker provided with an efficient mechanical stirrer, and add 40 g. of copper powder (either the precipitated powder or copper bronze which has been washed with a little ether). Suspend the fluoborate in about 200 ml. of water and add it slowly to the well-stirred mixture. Add 4-5 ml. of ether from time to time to break the froth. The reaction is complete when all the diazonium compound has been added. Transfer the mixture to a large flask and steam distil until no more solid passes over (about 5 litres of distillate). Filter off" the crystalline solid in the steam distillate and dry upon filter paper in the air this o-dinitrobenzene (very pale yellow crystals) has m.p. 116° (t.c., is practically pure) and weighs 29 g. It may be recrystallised from alcohol the recrystallised solid melts at 116-5°. 

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