XX. METHODS FOR THE ANALYSIS OF COCOA AND COCOA 

 PRODUCTS. PROVISIONAL. 



FPage 148.] 

 1. Moisture. 

 Proceed as directed under "VI. General Methods," page 38. 



2. Ash. 

 Proceed as directed under "VI. General Methods," page 38. 



3. Soluble Ash. 

 Proceed as directed under "X. Saccharine Products," 3 (c), page 68. 



4. Ash Insoluble in Acid. 



Proceed as directed under "XXIV. Spices," section 5, page 162. 

 5. Alkalinity of Ash. 



Treat the entire ash from 2 grams of the material as directed under "X. Saccha- 

 rine Products," 3 (e), page 69. 



6. Total Nitrogen. 

 Determine total nitrogen by the Kjeldahl method, "I. Fertilizers," 4, page 5. 



7. Theobromin and Caffein. <* 



Boil 10 grams of the powdered material and 5 grams of calcined magnesia for 30 

 minutes with 300 cc of water. Filter by suction on a Buchner funnel, using a round 

 disk of filter paper. Transfer the material and paper to the same flask used for the 

 first boiling, add 150 cc of water and boil for 15 minutes. Filter as before and repeat 

 the operation of boiling and filtering. Wash once or twice with hot water. Evapo- 

 rate the united filtrates (with ignited quart/, sand if sugar be present) to complete 

 dryness in a " Hoffmeister Schalchen" or other suitable thin glass dish of about 300 cc 

 capacity. Grind the dish with contents to a coarse powder in a mortar provided with 

 a suitable cover to prevent mechanical loss. Transfer to the inner tube of a Tollens, 

 Johnson, or Wiley fat extractor, and dry thoroughly in a water oven. Extract with 

 chloroform for eight hours, or until the theobromin and caffein are completely removed, 

 into a weighed flask.fr Distil off the chloroform and dry the residue at 100 C. to con- 



aDecker-Kunze method. Schweiz. Wochens. Chem. Pharm., 1902, 40: 527, 530, 541, 545, 553-557; 

 abstract Chem. Centrbl., 1903, 74 : 62. 



bit Is Important that the material be thoroughly <lry; that an extractor be used which permits of 8 

 hot extraction, and that a considerable volume of chloroform pass through the material. 



254 



