THE  AMEEIOA]:^r 
JOURNAL  OF  PHARMACY 
OCTOBER,  iQii 
 M-IO  : 
A  NOTE  ON  THE  ASSAY  OF  FORMALDEHYDE. 
By  Elias  Elvove. 
Hygienic  Laboratory,  U.   S.   Public  Health  and  Marme-Hospital  Service, 
Washington,  D.  C. 
It  has  been  shown  by  WilHams  ^  that  the  two  different  types 
of  methods  for  estimating  formaldehyde,  namely,  those  dependent 
on  the  oxidation  of  the  formaldehyde  and  those  dependent  on  its 
forming  condensation  products,  do  not  yield  concordant  results. 
In  explanation  of  this  discrepancy,  Williams  advances  the  view  that 
"  either  the  condensation  reactions  are  not  complete  or  a  small  part 
of  the  formic  acid  is  oxidized  farther."  He  also  reaches  the  con- 
clusion that  the  hydrogen  peroxide  method  is  the  most  satisfactory 
for  strong,  impure  solutions ;  while  "  the  potassium  cyanide  method 
is  recommended  for  dilute,  impure  solutions."  Recently,  the  writer 
has  had  occasion,  in  connection  with  the  study  of  embalming  fluids  - 
which  has  been  in  progress  in  this  laboratory,  to  make  a  compara- 
tively large  number  of  determinations  of  the  quantity  of  free  for- 
maldehyde in  these  fluids.  Owing  to  the  possible  presence  in  such 
fluids  of  substances  other  than  formaldehyde  which  on  oxidation  will 
yield  acids  (thus  rendering  the  hydrogen  peroxide  method  inappli- 
cable), or  other  reducing  substances  (thus  invalidating  the  iodomet- 
ric  method),  it  was  found  necessary  to^  resort  to  one  of  the  con- 
densation methods,  and  the  potassium  cyanide  method  was  chosen. 
It  became  of  interest,  therefore,  to  look  into  the  points  raised  by 
Williams  as  to  the  discrepancy  of  the  results  obtained  by  the  oxi- 
^  Jour.  Amer.  Chem.  Soc,  27,  596-601  (1905). 
^It  is  expected  that  the  resuUs  of  this  study  will  shortly  be  published  as 
a  Hygienic  Laboratory  Bulletin. 
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