XXIX. METHODS FOR THE ANALYSIS OF DRUGS. 



[Page 201.] 



2. Determination of Alkaloids. 

 (a) TOTAL EXTRACTION METHOD. 



Into a 200 cc 'flask weigh 10 grains of the powdered drug, add about 75 cc of ether- 

 chloroform mixture (5 to 1 by volume), rotate, and add 5 cc of a mixture of 40 cc of 

 strong ammonia water with 60 cc of alcohol, cork, shake well and often during one 

 hour, and let stand over night. Transfer as much of the mixture as possible to a small 

 percolator, the neck of which is provided with a purified cotton plug, receiving the 

 percolate in a beaker or flask. Rinse the residue in the flask into the percolator with 

 additional portions of the ether-chloroform' mixture, packing it down moderately with 

 a glass rod, and continue the percolation with the same mixture until the percolate 

 does not give an alkaloidal reaction, or at most only an opalescence when 2 cc are evap- 

 orated, and the residue is treated with N/10 hydrochloric acid, the mixture filtered 

 and the filtrate tested with Mayer's solution. Evaporate or distil the percolate to 

 about 10 cc at a temperature not exceeding 70 C. Transfer to a separator, and rinse 

 the vessel with two portions of 20 cc each of ether, alternating with two portions of 

 10 cc each of 2 per cent sulphuric acid. Shake out, making sure that the reaction is 

 acid, and repeat the operation three times with 15 cc of the same strength of acid, 

 filtering the acid solutions into another separator through a 7 cm filter, and rinsing the 

 latter with a few cubic centimeters of water. Wash the acid solution with 10 cc of 

 ether-chloroform mixture (1 to 3 by volume), discarding the latter, and if colored 

 repeat until no more color is required. Make the solution alkaline with ammonia 

 water and shake out with four successive portions of about 20 cc each of ether-chloro- 

 form mixture (1 to 3); collect the latter in a separator, wash with 5 cc of water, trans- 

 fer the ether-chloroform mixture to a tared flask or beaker, rinsing the separator with 

 a small portion of ether-chloroform, and evaporate the solvent at a temperature not 

 exceeding 70 C. 



(1) Gravimetric. Add 3 cc of ether, evaporate and dry to constant weight at a tem- 

 perature not exceeding 70 C. Report weight of alkaloidal residue. 



(2) Volumetric. Dissolve the residue in about 10 cc of neutral alcohol, add 25 cc 

 of water, 3 to 15 drops of cochineal indicator solution, measure in from a burette a 

 slight excess of N/50 sulphuric acid, mix intimately, and titrate buck with N/50 

 potassium hydroxid. Report net amount of N/50 acid required. 



(b) ALIQUOT METHOD. 



Into a 200 cc flask weigh 15 grams of the powdered drug, add 150 cc of ether-chloro- 

 form mixture (5 to 1 by volume), cork, and shake often for several minutes. Add 10 cc 

 of ammonia water (10 per cent), shake frequently during one hour, and let stand over 

 night. Add 15 cc of water, or sufficient to agglomerate the drug, shake, let settle a 

 few minutes, and then decant 75 cc of the clear solution into a graduated cylinder. 

 Transfer the solution to a separator, rinsing the cylinder with a few cubic centimeters 

 of ether-chloroform, and shake out with 20 cc (or sufficient to render acid) of 2 per cent 

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