Am,  Jour.  Pharm. ) 
September,  1911.  J 
Colorimetric  Test  for  Caramel. 
411 
of  the  untreated  material.  A  number  of  experiments  which  we 
have  recently  made  with  one  of  these  products,  designated  as  Thy- 
roid Proteid,  have  failed  to  confirm  this  hypothesis.  These  recent  ex- 
periments indicate  even  more  conclusively  than  our  previous  work, 
the  constant  behavior  of  the  thyroid-iodine  substance  and  the  close 
relation  between  the  iodine  content  and  the  physiological  activity 
of  both  the  desiccated  thyroids  and  the  new  Thyroid  Proteid. 
COLORIMETRIC  TEST  FOR  CARAMEL.^ 
By  F.  a.  Upsher  Smith,  Pharmaceutical  Chemist. 
Within  the  past  year  the  question  of  standardizing  the  color  of 
Caramel  has  been  engaging  the  attention  of  pharmaceutical  workers. 
Dr.  George  A.  Menge  recently  suggested  the  preparation  of  a 
standard  solution  of  Caramel  by  boiling  on  a  water  bath  for  five 
minutes  one-half  gram  of  Sugar  with  5  c.c.  of  a  mixture  of  Sul- 
phuric Acid  2  c.c.  and  water  10  c.c.  The  resulting  mixture, 
partially  cooled  by  the  addition  of  25  c.c.  cold  water,  neutralized 
with  Potassium  Hydroxide  Solution  and  finally  diluted  to  100  c.c. 
forms  the  standard  color  with  which  to  compare  commercial  samples 
of  Caramel. 
The  standard  that  I  have  used  for  several  years  seems  to  me 
to  be  one  that  is  more  readily  applicable,  as  the  materials  are  always 
on  hand  and  the  method  is  a  simple  and  quick  one.  The  method 
consists  in  matching  a  given  sample  of  Caramel  against  a  standard 
color  consisting  of  a  Nesslerized  solution  of  Ammonia.  For  carry- 
ing out  the  test,  make  a  stack  solution  of  Ammonium  Oxalate  by 
dissolving  .0417  gm.  of  Monohydrated  Ammonium  Oxalate,  in 
crystals,  in  i  litre  of  distilled  water.  Prepare  the  standard  color 
by  taking  10  c.c.  of  this  stock  solution,  adding  38  c.c.  of  water  and 
2  c.c.  of  Nessler's  Solution. 
Match  the  standard  color  with  the  Caramel  prepared  as  follows : 
Dissolve  I  gm.  of  the  Caramel  in  water  and  make  up  to  i  litre. 
Run  the  solution  from  a  burette  into  a  Nessler  glass  until,  on  dilution 
with  distilled  water  to  50  c.c,  it  exactly  matches  the  standard  color. 
.  *  Read  before  the  annual  Convention  of  the  Minnesota  State  Pharma- 
ceutical Association,  Duluth,  Minn.,  July  12,  1911. 
