Am.  Jour.  Pliarm. ") 
Nov.,  1885.  j 
Assay  of  Ipecac. 
539 
nearly  full  with  the  mixture  of  ether^  ammonia,  and  alcohol,  and  set 
aside,  shaking  occasionally,  for  twenty-four  hours.  Weigh  the  flask  with 
its  contents  before  removing  the  cork ;  decant  as  much  of  the  clear 
fluid  as  practicable,  taking  care  to  operate  rapidly  to  avoid  evaporation. 
Immediately  cork  the  flask  again  and  weigh.  You  may  now  separate 
the  alkaloid  from  the  decanted  portion  of  ether  by  shaking  repeatedly 
with  acid  water,  and  again  washing  out  from  the  aqueous  solution, 
rendered  alkaline,  with  chloroform,  but  identical  results  can  be  obtained 
more  rapidly  by  merely  evaporating  the  ether  after  addition  of  water 
containing  10  minims  of  6  per  cent,  sulphuric  acid,  and  titrating  the 
aqueous  solution  (made  up  to  20  cc.)  with  Mayer's  reagent. 
The  calculation  of  the  assay  is  not  diflicult.  You  have  as  data  total 
weight  of  solvent  used,  weight  of  portion  of  solvent  with  contained 
alkaloid,  resins,  etc.  You  may  assume  that  the  solvent  has  taken  up 
in  all  5  per  cent,  of  material  from  the  ipecac.  This  will  amount  to- 
2*5X*05=0'125,  to  be  added  to  the  weight  of  the  total  solvent — a 
quantity  so  trifling  that  it  may  be  neglected  in  practice — since  this 
assay  is  not  close  enough  to  render  important  minute  fractions. 
Suppose  the  weight  of  the  solvent  to  have  been  40  grams,  the  portion 
decanted  26  grams,  and  the  alkaloid  obtained  from  this  decanted  fluid 
to  have  been  0'055  grams  (=5' 82  cc.  of  the  reagent  used).  Then, 
26:40 ::  '055  :x,  x  being  the  quantity  of  alkaloid  contained  in  the  2*5 
grams  of  drug  used.  Solving  the  proportion,  40  X '055-^26— -0846. 
Since  the  quantity  of  drug  used  was  2*5  grams,  this  result  multiplied 
by  4,  with  the  decimal  points  removed  one  place  toward  the  right,  will 
give  the  per  cent,  (approximately)  of  alkaloid  in  the  drug,  in  the  above 
^example,  3*384  per  cent. 
The  results  I  have  obtained  by  this  method  of  assay  have,  however,, 
been  unsatisfactorily  low,  and,  until  some  of  the  details  are  a  little 
more  fully  worked  out,  I  regard  it  only  as  a  plan  promising  well.  I 
have  substituted  for  the  ether  in  this  process  petroleum  benzin,  and 
mixtures  of  chloroform  and  ether,  the  results  in  the  former  instance 
wholly  disappointing,  and  in  the  latter  not  as  satisfactory  as  where 
ether  alone  was  used. 
I  believe  that  when  experiment  shall  have  determined  what  quantity 
of  solvent  is  required,  how  much  ammonia  should  be  used,  and  how 
long  the  maceration  should  continue,  the  process  will  prove  a  good  one, 
and  it  has  this  advantage  over  Dragendorff' s  process,  that  it  is  not  lia- 
ble to  give  results  above  the  truth.    In  experiments  recently  made,  I 
