460  Examination  of  Opium  Alkaloids.     {Aoctobe?  SiT™" 
If  about  0.001  Gm.  of  papaverine  hydrochloride  be  dissolved  in 
0.1  Cc.  of  sulphuric  acid  containing  in  each  Cc.  one  drop  of  formal- 
dehyde solution,  a  colorless  solution,  or  at  most  a  faintly  yellowish- 
green  color,  should  be  produced;  this  gradually  changes  to  a  deep 
rose,  which  lasts  for  some  time,  the  mixture  finally  becoming  brown 
(distinction  from  the  salts  ' of  morphine  and  its  esters,  which  im- 
mediately give  purple  or  violet  colors). 
If  about  0.001  Gm.  of  papaverine  hydrochloride  be  intimately 
mixed  with  about  0.001  Gm.  of  finely-powdered  potassium  ferri- 
cyanide  and  the  mixture  dissolved  in  0.2  Cc.  of  sulphuric  acid  con- 
taining in  each  Cc.  one  drop  of  formaldehyde  solution,  a  light  blue 
or  greenish-blue  color  should  be  produced  at  once;  this  gradually 
changes  successively  to  deep  blue,  violet  blue  (or  bluish  violet), 
emerald  green  and  finally  pale  brownish  yellow  (distinction  from 
other  opium  alkaloids).  Certain  other  oxidizing  agents,  such  as 
ammonium  vanadate,  cerium  oxide,  potassium  permanganate,  seleni- 
ous  acid,  and  sodium  ortho-arsenate,  also  give  the  reaction  with 
slight  individual  variations  in  the  shades  of  color  produced. 
If  0.01  Gm.  of  papaverine  hydrochloride  be  dissolved  in  0.1  Cc. 
of  sulphuric  acid,  the  solution  should  not  be  colored  more  than  very 
faintly  pinkish  or  brownish  (limit  of  the  salts  of  crypto  pine,  thebaine, 
etc.,  or  of  other  organic  impurities). 
If  0.1  Gm.  of  papaverine  hydrochloride  be  dissolved  in  10  Cc. 
of  water  and  a  few  drops  of  ferric  chloride  solution  added,  a  red 
coloration  should  not  be  produced  (absence  of  meconic  acid  or 
meconates) . 
If  0.1  Gm.  of  papaverine  hydrochloride  be  shaken  with  10  Cc. 
of  a  5  per  cent,  solution  of  potassium  hydroxide,  the  mixture  allowed 
to  stand  for  an  hour,  filtered,  and  2  Cc.  of  ammonium  chloride  solu- 
tion added  to  the  filtrate,  no  crystals  should  separate  within  twenty- 
four  hours  (absence  of  morphine  salts). 
If  0.1  Gm.  of  papaverine  hydrochloride  be  dissolved  in  10  Cc.  of 
water,  a  few  drops  of  a  saturated  aqueous  solution  of  iodic  acid 
added,  and  the  mixture  shaken  with  2  Cc.  of  chloroform,  the  chloro- 
form layer  should  not  be  colored  violet  (absence  of  morphine  salts). 
If  from  0.2  to  0.3  Gm.  of  papaverine  hydrochloride  be  weighed, 
dissolved  in  50  Cc.  of  hot  water,  a  slight  excess  of  very  dilute  am- 
monia water  added  with  stirring,  the  mixture  allowed  to  stand  over 
night,  filtered,  the  filtrate  shaken  with  several  successive  portions  of 
ether,  the  ether  solutions  combined,  washed  with  water,  and  evapor- 
ated, the  residue  if  any,  should  not  respond  to  tests  for  codeine. 
