THE  AMERICAN 
JOURNAL  OF  PHARMACY. 
OCTOBER,  1884. 
ESTIMATION  OF  NICOTINE. 
By  Emil  Scheffer. 
Several  methods  have  been  published  to  estimate  the  amount  of 
nicotine  in  tobacco,  but  for  its  estimation  in  different  preparations  of 
tobacco  we  have  only  the  volumetric  test  with  Mayer's  solution,  which, 
although  not  quite  perfect,  yet  gives  approximately  correct  results. 
The  writer  had  lately  to  make  a  large  number  of  estimations  of  nico- 
tine from  tobacco  extracts,  which  he  executed  according  to  Dragen- 
dorff's  method.1 
One  of  the  greatest  obstacles  for  correct  work  is  the  circumstance 
that  a  more  dilute  solution  of  nicotine  requires  a  larger  proportion  of 
Mayer's  solution  than  a  stronger  solution.  To  get  if  possibly  a  clue  to 
this  anomaly,  I  decided  to  prepare  pure  nicotine,  and  make  experi- 
ments with  it. 
Pure  nicotine  was  prepared  by  distilling  extract  of  tobacco  with 
caustic  soda ;  the  distillate  was  slightly  supersaturated  with  sulphuric 
acid  then  evaporated  and  treated  with  absolute  alcohol  to  separate  the 
sulphate  of  ammonium.  The  alcoholic  solution  of  sulphate  of  nico- 
tine was  evaporated  on  a  water-bath  to  drive  off  the  alcohol;  the 
watery  solution  of  residue  was  mixed  with  ether,  and  concentrated 
solution  of  caustic  soda  added.  After  repeated  strong  agitation  the 
mixture  was  allowed  to  separate ;  the  ethereal  solution  was  drawn  off 
with  a  pipette  into  a  tared  beaker,  and  the  ether  allowed  to  evaporate 
spontaneously.  When  the  odor  of  ether  had  disappeared,  the  remain- 
ing liquid,  which  had  a  slight  yellowish  tint,  was  weighed,  dissolved 
in  water,  and  the  amount  of  nicotine  in  it  ascertained  with  normal 
volumetric  solutions  of  hydrochloric  and  sulphuric  acids. 
The  neutralized  solutions  were  then,  with  the  addition  of  distilled 
water,  brought  to  a  certain  volume. 
'Die  chemisette  Werthbestimmung  einiger  stark  wirkenden  Droguen. 
Von  Dr.  G.  Dragendorff.    St.  Petersburg,  1874. 
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