THE  AMERICAN 
JOURNAL  OF  PHARMACY. 
FEBRUARY,  1889. 
GOLD  CHLORIDE  AND  SILVEE  NITRATE  AS  TESTS 
FOR  FIXED  OILS. 
By  Frank  X.  Mcerk,  Ph.  G. 
A  Contribution  from  the  Chemical  Laboratory  of  the  Philadelphia  College  of 
Pharmacy. 
Read  at  the  Pharmaceutical  Meeting,  January  15th. 
In  the  Pharm.  Ztschr.  f.  Russl,  1888,  721  (Am.  Journ.  Pharm., 
1889,  23),  E.  Hirschsohn  gives  as  a  reliable  and  easily  applied  test 
for  the  detection  of  cotton-seed  oil  the  behavior  of  this  oil  towards  a 
chloroformic  solution  of  gold  chloride  (1  gm.  to  200  cc),  and  asserts 
that  it  will  indicate  one  per  cent  in  admixture  with  olive  oil.  The 
procedure  is  to  take  5  cc.  of  the  oil  with  10  drops  of  the  gold  chloride 
solution  and  heat  for  twenty  minutes  by  placing  the  test  tube  in  a 
vessel  containing  boiling  water,  a  red  color  indicating  the  presence  of 
cotton-seed  oil.  With  a  view  of  confirming  this  apparently  valuable 
test  numerous  samples  of  commercial  oils  were  obtained,  on  which, 
however,  little  reliance  for  purity  could  be  placed ;  from  Mr.  Geo.  M. 
Behringer  were  received  samples  which  he  believed  to  be  pure,  based 
upon  confidence  placed  in  the  producer  as  well  as  upon  tests  made 
with  the  samples ;  other  samples  were  gotten  in  the  chemical  laboratory 
by  means  of  solvents. 
Before  giving  the  results  in  detail  it  may  be  well  to  state  that  the 
test  which  Hirschsohn  claims  as  so  characteristic  for  cotton-seed  oil 
was  also  obtained  with  the  oils  of  arachis,  ben,  poppy  (an  imported 
oil),  sesame  and  walnut  kernel.  To  ascertain  if  these  oils  were  con- 
taminated with  cotton-seed  oil,  or  probably  contained  a  common  prin- 
ciple, their  effect  upon  silver  nitrate  solution  was  tried,  using  the 
method  of  O.  Hehner  (Analyst,  September,  1888,  and  Am.  Jotjrn. 
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