Am.  Jour.  Pharm.) 
Sept.,  1883.  J 
Examination  of  Quinine  Pills. 
437 
in  sufficient  distilled  water^  acidulated  with  5  drops  of  concentrated 
sulphuric  acid,  so  as  to  make  the  solution  measure  20  cc.  exactly. 
A  tube  200  mm.  long  is  filled  with  this  solution,  placed  in  the  appa- 
ratus, and  polarized.  The  percentage  of  pure  quinine  is  determined 
from  the  following  table. 
Explanation  and  Table  for  the  quantitative  and  qualitative  analysis 
of  cinchona  alkaloids  by  means  of  the  polariscope  and  a  200  mm. 
polarizing  tube,  from  the  observations  by  Mathias  Rozsuyay. 
The  following  solutions  were  prepared : 
1,  Quinine  sulphate ;  2,  conchinine  (quinidine)  sulphate  ;  3,  cinchonidine 
sulphate ;  4,  cinchonine  sulphate,  of  each  1  gram  was  dissolved  in  20  cc. 
water  and  3  drops  cone,  sulphuric  acid. 
Each  salt,  chemically  pure,  was  made  by  Jul.  Jobst,  of  Stuttgart. 
These  solutions  deviate  the  polarizing  plane  as  follows : 
1,  Quinine  solution,  left  —  22° ;  2,  conchinine  solution,  right  -f-  31°  ; 
3,  cinchonidine  solution,  left  —  14°  ;  4,  cinchonine  solution,  right  +  25°. 
A  solution  of  the  sulphate  of  a  cinchona  alkaloid  of  the  above 
proportion,  which  does  not  correspond  with  the  divergence  indicated  is 
not  chemically  pure.  ^ 
As  commercial  quinine  sulphate  usually  contains  conchinine,  and 
•commercial  conchinine  sulphate  contains  cinchonidine,  the  first-named 
salt  should  be  examined  for  conchinine,  and  the  sulphate  of  this 
^alkaloid  for  cinchonidine,  which  is  readily  and  precisely  accomplished 
by  use  of  the  polariscope,  while  other  impurities  are  easily  detected 
by  well  known  reagents. 
If,  for  instance,  the  polarizing  plane  of  a  normal  solution  of  qui- 
nine sulphate  diverges  only  21°  instead  of  22°  towards  the  left,  the 
salt  is  then  contaminated  with  2  per  cent,  of  conchinine  sulphate, 
as  0-98  X  22  =  left,  21-56° 
and     0-02  X  31  =  right,  '62° 
Difference  =  left,  20-94° 
A  quinine  sulphate  solution  which  contains  5  per  cent,  of  conchi- 
□line  sulphate  shows  still  greater  diiference : 
0-95  X  22  --=  left,  20-90° 
0-05  X  31  =  right,  1-55° 
DifTerence  =  left,  19-35° 
