Phj/sical cuid Chemical Papers. 99 



THE QUANTITATIVE SEPARATION OF QUININE AND 



STRYCHNINE. 



By r,. X. Watson, 



NO TWO DRUGS are more generally prescribed together 

 than quinine and strychnine. They are found in such 

 preparations as pills, syrups, tablets, powders, glycerites and 

 elixirs. Owing to this fact their analysis becomes of impor- 

 tance to both the analyst and the toxicologist. 



The dose of strychnine is very small, about one-sixtieth of a 

 grain ; the ordinary dose of quinine is comparatively large, 

 two to five grains, the ratio of strychnine to quinine ranging 

 from 1:30 to 1:120. It is this relatively small proportion 

 of strychnine that renders the actual separation of these al- 

 kaloids one of the quite difficult problems confronting the 

 pharmaceutical chemist. 



Among the methods used by chemists to make this separation 

 are: First, the ferrocyanide method; second, the oxalate 

 method ; and third, the tartrate method. The ferrocyanide 

 method is based on the insolubility of strychnine ferrocyanide 

 in .strongly acid solution and the solubility of the quinine salt. 

 The objection to the method is that the separation is not sharp. 

 A small amount of quinine is carried down with the strychnine, 

 LHving a high apparent strychnine content. 



The oxalate method is based on the relative insolubility of 

 the oxalate of quinine and the solubility of the strychnine salt. 

 The results by this method are generally too low for the 

 .strychnine content. Results 50 per cent lower than the actual 

 strychnine content have been recorded. 



The tartrate method, recommended by Vanderkleed, is car- 

 ried out in a manner similar to the oxalate method. The 

 quinine is precipitated as a tartrate and separated by filtration 

 from the soluble strychnine tartrate. The tendency of this 

 method is to give low results for strychnine. 



Besides these gravimetric separation processes there are 

 colorimetric methods for the determination of strychnine in 

 the pre.sence of (juiuine, among them being the color produced 

 by strychnine in a sulphuric acid solution of potassium 

 (iichromate, and the color produced by oxidizing agents on 



