§ 183. SEPARATION BY PRECIPITATION. 193 



For the separation of morphine from narcotine by ether, see 

 § 187. Ether and chloroform (free from alcohol) can also be 

 used to separate the former from codeine and thebaine. Morphine 

 can be sej)arated from thebaine, codeine, and narcotine, by the 

 method of agitation ; the last three are removed by benzene 

 from ammoniacal solution, whilst scarcely traces of morphine are 

 dissolved. 



In a similar manner delphinine and delphinoidine may be sepa- 

 rated from stapliisagnne by agitation with ether, in which the 

 latter is insoluble ;^ after removing the first two, staphisagrine 

 may be extracted with chloroform. 



§ 183. Use of Salts, etc. ; Separation of Quinine and CincJwnidine, 

 etc.^ — Instances of the use of salts in the separation of alkaloids 

 may be found in the employment of tartrates for the quantitative 

 estimation of qiuinine and cinchonidine in the presence of quinidine 

 and cinchonine (cf. § 184, I.); by means of iodide of potassium or 

 sodium, quinidine can be separated from cinclionine and ' amorphous 

 alkaloid ' (cf. § 184, IV.). Wittstein recommended conversion into 

 oxalates in alcoholic solution for separating s^r?/c/minc and brucine;^ 

 quinine may be freed from cinchonidine by precipitation as heror 

 fathite^{ci. § 184, IL). 



The separation of calaharine from physostigmine by potassio- 

 mercuric iodide, has already been described in § 174 ; the same 

 method might perhaps be feasible with chelidonine and sanguinarine.^ 



Chlmide of gold can be used in separating muscarine from 

 amanitine, as the double salt of the former is more soluble in 

 water than that of the latter.^ 



Perchloride of platinum was the salt used in separating paytine 

 from the other bark alkaloids, as the double salt of platinum with 

 that alkaloid is very sparingly soluble in water. By means of the 

 same salt, ammonia may be separated from those alkaloids and 

 amides that yield double salts of greater solubility (§ 98). It 

 must, however, be borne in mind that certain alkaloids undergo 



•^ See the paper by Marquis and myself previously quoted. 



- Comp. Moens, loc. cit.j Johanson, Archiv d. Pharm, x. 418, 1877 ; 

 Hielbig, loc. cit. 



^ Vierteljahressclirift f. pract. Pharm, viii. 409, 1859. 



•* Compare Herapath, Pharm. Journ. and Trans. [1], xi. 448 ; xii. 6 ; de 

 Vrij [3], vi. 461 ; N. Tijdschr. voor de Pharm. 1881 ; Hielbig, loc. cit. 



^ See my ' Chem. Werthbestimmung, ' 102. 



^ Compare Harnack, Archiv f. exper. Pathol, und Pharmacol, iv. 82, 1875. 



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