Am.  Jour.  Pharni.  "I 
October,  1899.  J 
Alkaloidal  Assays. 
471 
tion  of  Dunstan  and  Short's1  method  of  separation  by  ferrocyanide 
we  have  found  to  work  fairly  well,  as  follows :  Another  portion  of 
the  alkaloidal  solution,  representing  2  grammes  of  the  nux  vomica, 
that  is,  50  c.c,  is  run  out  from  the  burette  into  an  Erlenmeyer  flask 
of  the  capacity  of  about  300  c.c,  and  to  the  contents  of  the  flask  10 
c.c.  of  a  2  per  cent,  solution  of  sulphuric  acid  is  added,  and  then 
water  enough  to  make  in  all  about  200  c.c.  Then  pour  in  25  c.c. 
of  a  5  percent,  solution  of  potassium  ferrocyanide,  stopper  the  flask, 
and  shake  continuously  for  about  half  an  hour.  Now  filter,  wash 
the  precipitate  on  the  filter  repeatedly  with  water  containing  1  per 
cent,  of  sulphuric  acid  till  a  few  drops  of  the  filtrate  diluted  with  a 
little  water  have  no  bitter  taste.  The  filter  is  then  pierced,  and  the 
precipitate  rinsed  with  use  of  the  wash-bottle  into  a  100  c.c.  flask. 
To  the  contents  of  the  flask  are  then  adced  20  c.c.  of  a  5  per  cent, 
solution  of  zinc  sulphate,  and  the  flask  kept  on  a  boiling  water-bath 
for  about  fifteen  minutes.  The  zinc  sulphate  decomposes  the 
strychnine  ferrocyanide,  zinc  ferrocyanide  is  precipitated,  and 
strychnine  sulphate  remains  in  solution.  The  flask  is  then  com- 
pletely cooled,  and  water  enough  added  to  make  100  c.c.  Of  this, 
150  c.c,  representing  again  1  gramme  of  the  nux  vomica,  but  de- 
prived of  the  brucine,  are  then  filtered  off  and  run  out  from  the 
burette  into  a  100  cc.  flask  containing  20  c.c  decinormal  iodine  so- 
lution and  about  2  c.c.  of  dilute  hydrochloric  acid.  The  amount  of 
iodine  consumed  by  the  strychnine  alone  is  then  determined  as 
above.  Let  it  be  b.  Then  b  x  43*9  (100  times  the  strychnine  fac- 
tor) gives  the  percentage  of  strychnine,  and  {a  —  b)  X  518  is  the 
percentage  of  brucine  in  the  nux  vomica.2 
Iodine  Con- 
sumed by  10 
Iodine    Consumed  by  10     C.c.     after  Found.  Contained. 
C.c.  before  the  Removal  of     the  Removal    Strych-      Bru-      Strych-  Bru- 
Brucine.  of  Brucine.       nine.       cine.       nine.  cine. 
I  0*0843132        0*032397        0*14        0*24        0*l6  0*22 
2  0*0843130         0*032397         0*I4         0'24         0*l6  0*22 
1  Pharm.  J.  Trans.  (3),  14,  290;  Am.  J.  Phaem.,  1883,  579.  Any  other 
method  of  separation  of  strychnine  and  brucine  may  be  used  with  the  iodome- 
tric  estimations. 
2  To  test  the  exactness  of  this  method,  we  prepared  a  solution  containing 
known  quantities  of  each  of  these  alkaloids,  and  determined  the  same  by  the 
described  method.  The  results,  as  can  be  seen  from  the  following  statement, 
are  fairly  satisfactory,  if  we  consider  the  well-known  difficulties  of  this  separa- 
tion. The  solution  contained  0*16  per  cent,  strychnine  and  0*22  per  cent,  bru- 
cine (anhydrous). 
