932 
Adulteration  of  Turpentine. 
(  Am.  Jour.  Pharm. 
(     December,  1920. 
When  turpentine  is  adulterated  to  the  extent  of  lo  per  cent,  or 
more,  a  careful  observer  familiar  with  turpentine  can  usually  deter- 
mine the  fact  by  one  or  more  of  the  following  simple  tests: 
Odor. — The  presence  of  kerosene,  gasoline,  benzol,  or  solvent 
naphtha  is  usually  revealed  by  its  odor.  Wood  turpentine  is  best 
distinguished  from  gum  spirits  by  its  odor.  The  odors  of  these 
materials  cannot  be  described;  they  can  be  learned  only  by  actual 
trial  and  experience.  Lack  of  the  characteristic  turpentine  odor  is 
good  ground  for  a  careful  test  to  determine  the  purity  of  the  sample. 
Grease  Spot. — Pour  a  little  of  the  suspected  turpentine  on  a  piece 
of  white  writing  paper.  If  the  bulk  of  the  sample  evaporates  rapidly 
from  the  paper,  leaving  a  greasy  spot  which  evaporates  very  slowly 
or  not  at  all,  the  turpentine  is  probably  adulterated  with  kerosene 
or  heavy  solvent  naphtha,  or  contains  a  large  percentage  of  heavy 
turpentine  which  will  not  distil  below  170°  C.  The  odor  of  the  grease 
spot  often  determines  the  nature  of  the  adulterant.  Greasy  spots 
around  bung  or  spigot  holes  of  turpentine  barrels  are  also  indicative 
of  these  adulterants. 
Bead. — When  a  perfectly  clean  dry  bottle  is  partly  filled  with 
turpentine  and  violently  shaken  for  a  moment  the  head  or  foam  that 
forms  will  immediately  pass  away  if  the  turpentine  is  pure  and  fresh. 
If  the  foam  persists  for  5  seconds  or  more,  the  turpentine  probably 
is  adulterated  or  old. 
Evaporation  Test. — Set  a  5 -inch  watch  glass  near  an  open  window 
where  a  gentle  air  current  can  blow  across  it.  Carefully  place  in  it 
5  cc.  of  the  turpentine,  so  that  the  glass  does  not  become  wet  with 
the  turpentine  beyond  the  edge  of  the  surface  of  the  liquid.  Then 
carefully  pipette  or  dip  out  2  Cc,  or  about  half  of  it.  Observe  the 
rim  of  the  turpentine  film  after  3  hours.  If  the  rim  is  continuous 
or  more  or  less  regular  in  outline,  the  turpentine  is  probably  pure. 
If,  however,  the  rim  is  made  up  of  a  chain  of  distinct  drops  or  beads, 
or  if  the  liquid  appears  to  flow  back  to  the  center  of  the  glass  in 
distinct  streams,  it  probably  is  adulterated  with  mineral  oil  or  is  an 
old  turpentine  of  high  specific  gravity.  The  unevaporated  residue 
will  also  smell  of  mineral  oil  if  kerosene  or  any  other  oil  which  is  less 
volatile  than  turpentine  has  been  used  as  an  adulterant. 
Needless  to  state,  if  all  these  simple  tests  are  definite,  there  can 
be  little  doubt  that  the  turpentine  is  adulterated.  When  these 
tests  are  negative,  however,  it  cannot  be  safely  assumed  that  it  is 
not  adulterated  to  a  small  extent  or  very  carefully  to  a  large  extent 
with  a  specially  prepared  turpentine  adulterant  or  substitute. 
