Solutions cont dilution

A. Ethyl Nitrite.—Two solutions are prepared. Solution I contains 620 g. (9 moles) of sodium nitrite (650 g. of technical 95 per cent), 210 g. (4.57 moles) of alcohol (285 cc. of 90 per cent denatured, or its equivalent) and water to make a total volume of 2500 cc. Solution II contains 440 g. of sulfuric acid (255 cc. of sp. gr. 1.84) and 210 g. of alcohol, diluted with water to 2500 cc. Ethyl nitrite may he generated cont inuously in gaseous form by allowing solution II to (low into solution I. 

Having accomplished the homogenization of the sample, extraction of free amino acids is usually a simple process of stirring the sample in an appropriate solvent. This is typically a dilute solution (0. IN) of hydrochloric acid (2,7). Elevated temperatures may be used to assist dissolution, but care must be taken not to damage the more acid-labile amino acids. More recently, Moret and Conte (8) report that 0.1N HC1 was not a suitable solvent for all types of food samples. For some types of meat samples, 5% trichloroacetic acid is reported to afford superior performance (for biogenic amines, also amino acids ). It is not unusual to see perchloric acid employed for extraction from meat tissues (also more commonly for biogenic amines). 

A solution containing 22 grams of y>aminophenylarsenoxidc and 18 15 grams of arsenic trichloride in 100 c.c. of methyl alcohol is slowly added to a well-coolestannous chloride in 200 c.c. of hydrochloric acid (density 1 19) and 200 c.c. of methyl alcohol. The product is brownish-yellow and cont ns 45 per cent, of arsenic. It is soluble in hot dilute hydrochloric acid and in moist pyridine, the acid solution yielding precipitates with dilute sulphuric acid and excess of sodium hydroxide. 

Several years ago, Braun, Kato, and Lipsky (142) showed that in the vapor solution and bulk liquids, benzene and its methylated derivatives appeared not to undergo efficient internal conversion or intersystem crossing from higher excited singlet states to form either Sj or Tj states. This was confirmed by Birks, Conte, and Walker (143) who postulated a scheme involving excimers of higher excited states, to explain their data and noted that benzene proved to be the exception amongst similar compounds in that the effect decreased on dilution. 

Vn/554 SPECIFIC REFRACTIVE INDEX INCREMENTS OF POLYMERS IN DILUTE SOLUTION TABLE 1. COnt d... 

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