ALKALOIDS AND ALKALOIDAL-TYPE PRECIPITATION 



gators might distinguish it. When, in some 

 study, alkaloids are isolated from plant ma- 

 terial on a small scale, and are not among 

 those commercially available, one usually 

 finds that, even though the plarit from which 

 they came is known, and the alkaloids found 

 are distinguished by analytical reactions, it 

 is still impossible to tell which one if any 

 corresponds to some previous^ studied al- 

 kaloid of that plant, without going through 

 most of the original procedure. This necessi- 

 tates a large quantity of material, obtaining 



Fig. 1. A well-known crystal test: morphine 

 with iodine-KI (aqueous solutions). 



""% 









''^. 



"t 





fh 



^* 



% 









^^' 



Fig. .3. A less-known alkaloidal crystal test: 

 codeine with Hglo-NaCN and Nal (aqueous solu- 

 tions). 



Fig. 4. A well-known crystal test: diacetylmor- 

 phine (heroin) with H2PtCl6 (aqueous solutions). 



: ■ >ti 



I 





Fig. 2. A well-known crystal test: morphine 

 with K2Cdl4 (aqueous solutions) . 



melting-points, and analyzing for elementary 

 composition, except in the rare event that a 

 sample of the original isolate can be obtained 

 for comparison. This kind of gap between 

 research and application is very common. 



Other Compounds with Aqueous Re- 

 agents. Alkaloids do not constitute a dis- 

 tinct chemical group. Their precipitation 

 with the "general alkaloidal reagents" de- 

 pends upon their being compounds of basic 



15 



