THE  AMERICAS" 
JOURNAL  OF  PHARMACY 
OCTOBER,  ipio 
THE  ASSAY  OF  IODOFORM  AND  IODOFORM  GAUZE. 
By  A.  H.  Clark. 
In  searching  the  available  literature  for  a  satisfactory  method 
for  the  determination  of  iodoform  in  medicated  gauze  and  also  for 
the  assay  of  iodoform,  the  method  of  Uts  (Apoth.  Ztg.,  18,  No.  98, 
Dec.  9,  1903,  869)  and  that  of  Gane  and  Webster  {Merck's 
Report,  18,  No.  1,  p.  13,  1909)  seemed  to  be  the  most  readily 
applicable. 
Uts  dissolves  the  iodoform  in  spirit  of  ether,  adds  fuming  nitric 
acid,  an  excess  silver  nitrate  V.S.,  and  heats  until  the  odor  of 
nitrous  acid  has  disappeared.  The  excess  of  silver  nitrate  V.S.  is 
then  determined  with  1/10  normal  ammonium  sulphocyanide  V.S. 
Gane  and  Webster  dissolve  the  iodoform  in  alcohol  and  ether 
in  the  proportion  of  3  parts  of  alcohol  to  1  part  of  ether.  Com- 
mercial nitrous  acid  is  then  added,  the  mixture  heated,  and  the 
excess  silver  nitrate  V.S.  determined  with  i/10  normal  potassium 
sulphocyanide  V.S.  Gauze,  lint,  etc.,  are  exhausted  with  ether 
and  the  ethereal  solution  treated  as  described. 
Both  methods  were  found  to  give  excellent  satisfaction.  In  the 
effort  to  shorten  the  method  as  applied  to  gauze,  I  found  that  it 
is  not  necessary  to  dissolve  the  iodoform  in  alcohol  or  ether, 
neither  is  the  fuming  nitric  acid  necessary.  Boiling  under  a  reflux 
condenser  for  one-half  hour  in  the  presence  of  alcohol  and  nitric 
acid,  U.S. P.,  is  sufficient  to  convert  all  of  the  iodine  to  silver 
iodide.  By  the  use  of  alcohol  alone  a  simultaneous  extraction  of 
the  gauze  and  determination  of  the  iodoform  may  be  carried  out, 
and  this  much  easier  than  if  ether  is  present.    Using  ether  for 
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