68, 69. ESTIMATION BY TITRATION. 63 



elude direct sunlight ; 500 cc. of spirit are poured in, and after 

 two hours 25 grams of slaked lime are added to the mixture. 

 The whole is then macerated for two days, and finally boiled fcr 

 half an hour on the water-bath. To the filtrate, together with 

 100 cc. of wash-alcohol, the results of two following extractions, 

 each with 250 cc. of spirit and 100 cc. washings, are added. 

 The mixture is neutralized with 25 drops of dilute sulphuric acid 

 (1 to 7) or more if much cinchonine is present. After stand- 

 ing twenty-four hours the spirituous solution is filtered, and 

 the alcohol recovered by distillation, the process being stopped 

 as soon as the liquid becomes cloudy (about 200 cc.); 15 cc. of 

 2 per cent, sulphuric acid are then added, and the evaporation 

 continued on the water-bath, carbonization being carefully avoided. 

 The residue is treated with water, the resin filtered off and 

 washed with a little dilute sulphuric acid. The alkaloid is then 

 precipitated by carbonate of soda, and the whole evaporated on 

 the water-bath to about 20 cc. After cooling, the resinous preci- 

 pitate is filtered off, rubbed down to a powder in a mortar with 

 water, retransferred to the filter, washed, dried, and weighed. 

 From the filtrate and wash-water the alkaloid is extracted by 

 chloroform, and the weight thus found added. For the separa- 

 tion of the more important bark alkaloids from each other, see 

 183, 184. 



68. Estimation lij Titration. If the alkaloid under examina- 

 *tion has a powerfully alkaline reaction, it may be separated by 

 the method of agitation, or according to 66, 67, and esti- 

 mated by titration with ~$ acid. A method of this kind has 

 been proposed by Schlossing and others for the quantitative 

 determination of nicotine in tobacco. 1 (See 179, 180.) 



69. Separation of two or more Alkaloids. In the methods 

 described for the estimation of alkaloids it was assumed that only 

 one was present. But two or more may be met with in the same 

 plant. In attempting their separation their behaviour to solvents 

 should be ascertained. Ether, for instance, may be used to separate 

 quinine from cinchonine, narcotine from morphine, delphinine from 

 delphinoidine. 



1 Annales de Chim. et de Phys. xix. 230 (Am. J. Pharm. xix. 68) ; also 

 ' Wittstein and Brandt, Vierteljahresschrift f. prak. Pharm. xi. 351, and xiii. 

 322 ; Liecke, Zeitschr. f. anal. Chem. iv. 492 ; Kosutany, Anal. Best, einiger 

 Bestandth. d. Tabakspflanze. Diss. Altenburg in Hungary, 1873. 



