XXIII. METHODS FOE THE ANALYSIS OF FLAVORING EX- 

 TRACTS. PROVISIONAL. 



VANILLA AND ITS SUBSTITUTES. 



1. Specific Gravity. 

 Determine as directed under " XIII. Wine," on page 83. 



2. Alcohol. 



Determine as directed under " XV. Distilled Liquors," on page 95. 



3. Glycerol. 

 Determine as directed under " XIII. Wine," on page 83. 



4. Determination and Identification of Vanillin, Coumarin, and Acetanilid. 

 (a) HESS AND PBESCOTT METHOD MODIFIED BY WINTON AND BAILEY.O 



Weigh 25 grams into a 200 cc beaker with marks showing volumes of 25 and 

 50 cc. Dilute to the 50 cc mark and evaporate in a water bath to 25 cc at a 

 temperature in the bath of not more than 70 C. Dilute a second time to 50 cc 

 and evaporate to 25 cc. Add normal lead acetate solution drop by drop until 

 no more precipitate forms. Stir with a glass rod to facilitate flocculation of 

 the precipitate, filter through a moistened filter, and wash three times with hot 

 water, taking care that the total filtrate does not measure more than 50 cc. 

 Cool the filtrate and shake with 20 cc of ether in a separatory funnel. Remove 

 the -ether to another separatory funnel and repeat the shaking of the aqueous 

 liquid with ether three times, using 15 cc each time. Shake the combined ether 

 solutions four or five times with 2 per cent ammonium hydroxid, using 10 ccj 

 for the first shaking and 5 cc for each subsequent shaking. Set aside the 

 combined ammoniacal solutions for the determination of vanillin. 



Wash the ether solution into a weighed dish and allow the ether to evaporate 

 at the room temperature. Dry in a desiccator, and weigh. Stir, the residue 

 for fifteen minutes with 15 cc of petroleum ether (boiling point 30 to 40 C.) 

 and decant the clear liquid into a beaker. Repeat the extraction with petroleum 

 ether two or three times. Allow the residue to stand in the air until apparently 

 dry, completing the drying in a desiccator. Weigh, and deduct the weight 

 from the weight of the residue obtained after the ether evaporation, thus 

 obtaining the weight of the coumarin. The petroleum ether residue, if ace-j 

 tanilid, should melt at about 112 C. and respond to Ritsert's tests (p. 158, d).J 



Allow the petroleum ether extract to evaporate at room temperature. If it 

 Is pure coumarin, it should have a melting point within a few degrees of 67 C. | 

 and respond to Leach's test. (See page 157, paragraph (c).) 



J. Amer. Chem. Soc., 1809, 21:256; 1902, 24:1128; 1905, 27:719. 



156 



