Ail.  JotJB.  Pharm.  ) 
June  1, 1871.  J 
Detection  of  Turmeric,  etc. 
259 
DETECTION  OF  TURMERIC  IN  POWDKRED  RHUBARB  AND 
YELLOW  MUSTARD. 
By  J.  M.  Maisch. 
Rhubarb  root  which  has  been  attacked  by  insects,  or  deteriorated  in 
<)onsequence  of  dampness  and  heat,  is  by  some  dealers  sent  to  the  mills 
4ind  ground  together  with  some  sound  rhubarb,  or,  if  the  color  is  not 
sufficiently  bright,  turmeric  is  added,  and  the  powdered  rhubarb  finds 
ats  way  afterwards  into  the  hands  of  the  unsuspicious  as  a  prime 
article.  The  fraud  may  be  detected  in  a  few  minutes  in  the  follow- 
ing manner  : 
A  small  quantity  of  the  suspected  rhubarb  is  agitated  for  a  minute 
•or  two  with  strong  alcohol,  and  then  filtered.  Chrysophanic  acid 
being  sparingly  soluble  in  this  menstruum,  the  brown  yellow  color  of 
the  filtrate  is  due  to  the  resinous  principles  of  rhubarb  mainly  ;  if 
-adulterated  with  turmeric,  the  tincture  will  be  of  a  brighter  yellow 
^hade.  A  strong  solution  of  borax  produces  in  both  tinctures  a  deep 
Ted  brown  color.  If  now  pure  muriatic  acid  be  added  in  large  excess, 
the  tincture  of  pure  rhubarb  will  instantly  assume  a  light  yellow 
43oior,  while  the  tincture  of  the  adulterated  powder  will  change  merely 
to  a  lighter  shade  of  brown  red.  The  test  is  a  very  delicate  one,  and 
is  based  on  the  liberation  of  boracic  acid,  which  impai-ts  to  curcumin 
color  similar  to  that  produced  by  alkalies,  while  all  the  soluble 
^principles  of  rhubarb  yield  pale  yellow  solutions  in  acid  liquids. 
The  same  test,  applied  in  the  same  manner,  is  also  applicable  to 
ground  mustard  seed.  The  seeds  of  Sinapis  alba  yield  a  powder  of  a 
yellow  grey  color,  entirely  distinct  from  the  color  of  yellow  mustard 
met  with  in  the  market.  Agitated  with  alcohol  and  filtered,  a  turbid 
solution  is  obtained,  which  assumes  a  bright  yellow  on  the  addition  of 
the  borax  solution,  and  becomes  colorless  or  whitish  again  on  being 
supersaturated  with  muriatic  acid.  If  the  mustard  be  colored  with 
turmeric,  the  filtrate  has  a  yellow  tint,  becomes  brown  red  by  borax, 
and  retains  the  color  on  the  addition  of  muriatic  acid.  All  the  so- 
called  yellow  mustard  of  our  commerce  which  I  have  had  occasion  to 
-examine,  whether  ground  in  England  or  in  the  United  States,  contains 
turmeric.  This  practice  ought  to  be  discountenanced ;  for,  under  the 
yellow  color  imparted  by  curcuma,  adulteration  of  mustard  may  be 
<3arried  on  to  an  almost  indefinite  extent,  if  strength  be  supplied  by 
the  addition  of  a  little  capsicum. 
