Am.  Jour.  Pharm. 
September,  1898. 
f-}     Black  and  White  Mustard  Seed. 
435 
detection  in  mustard,  among  which  those  yielding  the  most  satis- 
factory results  are  herein  presented. 
This  method  was  suggested  in  our  report4  of  1895.  It  is  easy  of 
execution  and  rather  sharp  in  reaction.  We  would  suggest  for  it 
the  following  slightly  modified  directions : 
Put  into  a  large  test  tube  1  gramme  of  the  ground  black  mustard 
seed  and  ioc.c.  of  water  and  I  c.c.  of  iodine  test  solution,  U.S.P.  Boil 
until  the  brown  color  has  disappeared.  Cool  the  liquid  and  add  (by 
means  of  a  pipette)  /  drop  of  iodine  test  solution,  U.S.P.,  allowing  it  to 
flow  down  the  side  of  the  test  tube  and  mix  gradually  with  the  upper 
part  of  the  liquid.  If  as  little  as  o-i  per  cent,  of  starch  is  present, 
a  distinct  and  quite  permanent  blue  or  greenish-blue  layer  appears 
in  the  upper  part  of  the  fluid,  which,  by  contrast,  is  very  percep- 
A.  Copper  Sulphate  and  Iodine. 
Solutions. — (1)  Copper  Sulphate  Solution  (0-2  per  cent.).  Dissolve 
/  gramme  of  pure  crystallized  copper  sulphate  in  water  to  make 
500  c.c.  of  solution. 
(2)  Solution  of  Iodine  (2  per  cent.),  iodine  test  solution,  U.S.P. 
Directions. — Put  1  gramme  of  the  powdered  black  mustard  into  a 
perfectly  dry  test  tube,  add  10  c.c.  of  the  (0-2  per  cent.)  copper 
solution  and  boil.  No  odor  of  mustard  oil  will  be  developed.  Cool, 
and  add  from  1  to  3  or  four  drops  of  iodine  test  solution,  allowing 
it  to  flow  down  the  side  of  the  test  tube,  taking  care  to  leave  a  layer 
of  uniodized  liquid  below,  in  order  that  the  contrast  in  color  may  be 
observed.  The  upper  layer  will  turn  blue  if  as  little  as  0  3  per  cent, 
of  starch  is  present. 
Remarks. — The  copper  solution  commended  is  sufficiently  dilute 
to  offer  no  interference  with  the  color  reaction  on  account  of  its 
own  blue  color.  It  was  found  that  at  no  practical  concentration 
(beginning  at  2  per  cent.)  does  the  color  of  the  copper  solution  in- 
terfere with  the  sensitiveness  of  the  test.  This  strength  (02 
per  cent.)  is  sufficient  to  prevent  the  formation  of  oil  of  mustard 
even  upon  boiling,  and  we  prefer  it  to  more  concentrated  solutions. 
By  careful  manipulation  the  presence  of  02  per  cent,  of  starch 
can  be  distinctly  demonstrated  by  this  test.    Yet,  from  0-3  per  cent. 
I.  IODINE  METHOD. 
tible. 
11. 
COPPER  METHODS. 
