FLA YOKING EXTAKCTS. 69 



XII.-FLA YOKING EXTRACTS. 



By A. S. MITCHELL, 

 Chemist of State Dairy and Food Commission, Milwaukee, Wis. 



Flavoring extracts consist of three classes of preparations tinctures, spirits, and 

 artificial essences. Each class needs specific treatment, varying in detail with the 

 object sought. In quantitative examination of either tincture of vanilla or spirits of 

 lemon, it is essential to carry out comparative tests upon similar products of known 

 purity and strength. Many of the methods recommended for lemon may be readily 

 adapted to the examination of other spirits containing volatile oils. 



(A) VANILLA AND ITS SUBSTITUTES. 



1. DETERMINATION OF TOTAL SOLIDS. 



Weigh 25 grams of the extract into a large, flat-bottomed dish which contains 

 enough freshly ignited asbestos to absorb it; dry from twenty to twenty-four hours 

 in a water-jacketed oven. 



2. DETERMINATION OF ASH. 



Weigh about 10 grams of the extract in a flat-bottomed platinum dish, evaporate 

 to dryness on a water bath, heat slowly until intumescence ceases, and ignite in a 

 muffle at a low red heat until a white ash is obtained. 



3. EXAMINATION OF ASH. 

 Proceed as directed on page 106. 



4. DETECTION AND DETERMINATION OF COUMARIN AND VANILLIN.* 



Dealcoholize 50 grams of the extract in a glass evaporating dish upon a water 

 bath at a temperature of about 80 C. ; add water from time to time to retain the 

 original volume. After removal of the alcohol, 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; wash three times 

 with a few cubic centimeters of hot water. Cool the filtrate and extract with ether 

 by shaking out in a separatory funnel. Use 15 to 20 cc of ether at each separation 

 and repeat the shaking out three or four times, or until a few drops of the ether 

 evaporated upon a watch glass leaves no residue. Place the combined ether extracts 

 containing all of the vanillin and coumarin in a clean separatory funnel and shake 

 out repeatedly with from 5 to 10 cc of 7 per cent ammonia. b Repeat the treatment 

 with ammonia once or twice after the fractions cease to be colored yellow. 



Set asr-idi' the combined ammoniacal solutions for the determination of vanillin. 



Wash the ether solution into an evaporating dish and allow the ether to evaporate 

 at ordinary temperature. Extract the residue by treating it at room temperature 

 with 5 to 10 cc of a petroleum fraction boiling between 30 and 40 C. ; allow it to stand 

 several minutes and then decant into a dried, weighed evaporating dish. Repeat the 

 extraction with petroleum ether until a drop evaporated on a watch glass leaves no 

 residue. Allow the petroleum ether to evaporate at room temperature; dry in a 

 dessicator over sulphuric acid and weigh as coumarin. 



The residue should be crystalline and have a melting point of 67 C. This, with the 

 characteristic odor of coumarin, obtained by warming slightly, is sufficient for its 

 identification. 



Hess:m<l 1'n-scotl. .lour. Am. ('hem. Six;., 1899, 21, 25(i. 

 b Winton pivkTs '. piTcriit nimnonia. 



