Am.  Jour.  Pharm. 
Dec,  1918. 
Determination  of  Morphine. 
855 
platinum  dish)  almost  to  dryness.  The  dish  is  cooled  and  enough 
water  is  added  to  make  the  volume  of  its  contents  as  nearly  as 
possible  5  Cc.  To  this  is  added  5  Cc.  of  chloroform  and  about  3 
drops  of  concentrated  ammonium  hydroxide  solution  or  as  much 
more  as  is  needed  to  produce  decided  alkalinity.  The  liquids  are 
well  mixed  with  a  stirring  rod  which  is  caused  to  scratch  the  bottom 
of  the  dish  lightly  and  to  break  up  undissolved  aggregates,  thus 
promoting  rapid  precipitation  of  the  morphine.  When  the  latter  sub- 
stance begins  to  separate  the  dish  is  covered  and  set  aside  for  four 
hours,  during  which  time  it  should  be  occasionally  agitated  with  a 
rotary  motion. 
The  contents  of  the  dish  are  filtered  through  a  cotton  plug  with 
the  aid  of  suction,  the  dish  and  morphine  being  washed  with  small 
quantities  of  cold  water  (morphinated  water  may  be  substituted  at 
the  analyst's  discretion)  till  the  washings  become  colorless.  About 
10  Cc.  of  water,  if  care  is  used,  should  suffice  for  this  washing,  in 
most  cases. 
The  morphine  thus  obtained  is  yellowish  and  not  pure  enough  to 
give  reliable  results  on  titration.  The  plug  with  adherent  alkaloid 
is  lifted  into  a  small  separating  funnel.  The  morphine  remaining 
in  the  dish  is  dissolved  in  a  small  quantity  of  dilute  sulphuric  acid 
and  the  solution  is  transferred  to  the  separating  funnel  through  the 
funnel  previously  used  for  the  filtration.  The  dish  and  funnel  are 
then  well  washed  with  water.  Washings  and  acid  together  should 
not  exceed  20  Cc. 
The  solution  of  morphine  is  made  sufficiently  alkaline  to  liberate 
all  the  alkaloid  by  the  addition  of  either  a  few  drops  of  concen- 
trated ammonium  hydroxide  or  a  saturated  solution  of  sodium 
hydrogen  carbonate.  It  is  then  shaken  for  3  minutes  with  25-30  Cc. 
of  chloroform-alcohol  mixture  (2  volumes  of  chloroform  to  1  volume 
of  alcohol).  After  separating  the  lower  layer  of  liquid,  the  extrac- 
tion is  exactly  repeated  on  the  aqueous  layer  with  three  further 
similar  quantities  of  the  chloroform-alcohol  mixture,  the  time  of 
shaking  being  3  minutes  in  every  case. 
The  combined  extracts  are  distilled  on  the  water  bath.  The 
residue  of  almost  white  morphine  is  dissolved  in  a  known  volume  of 
decinormal  sulphuric  acid,  the  excess  of  which  is  titrated  with  deci- 
normal  or  twentieth-normal  sodium  hydroxide.  Lacmoid,  cochineal 
or  methyl  orange  are  suitable  indicators. 
The  weight  of  morphine  found  by  this  titration  will  be  10/22  of 
