XX. FLAVORING EXTRACTS. 

 VANILLA EXTRACT AND ITS SUBSTITUTES. 



1 SPECIFIC GRAVITY.-TENTATIVE. 



20°C 

 Determine the specific gravity at -p— ' by means of a pycnometer 



2 ALCOHOL.-OFFICIAL. 

 Proceed as directed under XVII, 2 or 3. 



3 GLYCEROL.— TENTATIVE. 



Proceed as directed under XVI, 7, 8 or 9, the method selected depending upon 

 the amount of sugar present, employing an amount of the sample containing 0.10- 

 0.40 gram of glycerol. 



VANltLlN AND COUMARIN. 

 Modified Hess and Prescott Method^. — Tentative. 



(This method is not applicable to concentrated vanillin and coumarin 



preparations in which the amount of vanillin and coumarin present 



exceeds the quantity dissolved by 100 cc. of water at 20°C. 



In such cases employ a smaller amount of the sample 



and dilute to 50 cc.) 



4 PREPARATION OF SOLUTION. 



Measure 50 cc. of the extract at 20°C. into a 250 cc. beaker with marks showing 

 volumes of 80 and 50 cc, dilute to 80 cc. and evaporate to 50 cc. on a water bath kept 

 at TO^C. Dilute again with water to 80 cc. and evaporate to 50 cc. Transfer to a 

 100 cc. flask, rinsing the beaker with hot water; add 25 cc. of 8% lead acetate solu- 

 tion; make up to the mark with water, shake and allow to stand 18 hours (over- 

 night) at 37°-40°C. Decant into a small, dry filter, reserving the filtrate for the 

 determination of vanillin and coumarin, the normal lead number, 6, and the 

 residual color, 14. 



5 DETERMINATION. 



Transfer a 50 cc. aliquot of the filtrate to a separatory funnel and extract with 4 

 successive 15 cc. portions of ether (previously washed twice with an equal volume 

 of water to remove alcohol). Wash the combined ether solutions 4 or 5 times with 

 2% ammonium hydroxid solution (2% NH3 by weight), using 10 cc. the first time 

 and 5 cc. thereafter, and reserve the ether solution for the determination of cou- 

 marin. Slightly acidify the combined ammoniacal solutions with hydrochloric 

 acid; cool and extract in a separatory funnel with 4 portions of washed ether, using 

 about 40 cc. altogether. Evaporate the ethereal solutions at room temperature, 

 dry over sulphuric acid and weigh. If the residue is considerably discolored or 

 gummy, re-extract in the dry state with boiling petroleum ether (b. p. 40°C. or 

 below) not less than 15 times; evaporate the solvent, dry and weigh. The residue 

 should now be white, crystalline vanillin, with a melting point of approximately 



259 



