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Some  Alkaloidal  Assays. 
[  A.m.  Jour.  Pharm. 
I     October,  1906. 
SOME  ALKALOIDAL  ASSAYS.1 
By  H.  M.  Gordin. 
While  most  of  the  methods  adopted  in  the  U.S.P.  of  1900  for  the 
alkaloidal  assay  of  drugs  and  galenicals  are  very  good,  there  are  a 
few  among  them  that  either  do  not  work  at  all  or  are  so  compli- 
cated that  they  will  hardly  ever  give  concordant  results  in  the  hands 
of  different  chemists.  To  the  first  class  belong  the  assays  of  aconite 
root,  its  fluid  extract  and  the  fluid  extract  of  ipecac.  In  these 
assays  we  are  directed  to  filter  the  first  acid  liquids  obtained  in  the 
method,  but  as  these  liquids  are  very  thick  and  slimy  they  soon 
clog  up  the  filter  and  the  assays  cannot  be  finished. 
To  the  second  class  belong  several  assays  which  by  introducing 
certain  modifications  into  the  pharmacopoeial  methods,  or  replacing 
the  latter  by  others,  could  be  made  simple  and  capable  of  giving 
concordant  results. 
Such,  for  example,  are  the  assays  of  extracts  of  physostigma  and 
conium  and  a  few  others.  I  therefore  propose  the  following  methods 
which  can  also  be  applied  to  many  other  cases  and  which,  particularly 
when  used  in  combination  with  the  shaking-tube  percolator  described 
in  a  previous  paper  (American  Journal  of  Pharmacy,  1905,  p.  463) 
and  the  two  special  separating  funnels  described  below,  will  be  found 
to  be  simple,  short  and  exact.  While  the  principles  in  some  of 
these  methods  are  not  strictly  new,  I  do  not  know  of  their  ever 
having  been  used  in  the  way  here  described. 
These  principles  consist  in  avoiding  the  distillation  of  ethereal 
solutions  to  dryness  and  the  substitution  of  fixed  alkali  or  alkali 
carbonate  for  ammonia  for  the  liberation  of  alkaloids  from  the  aque- 
ous solutions  of  their  salts.  While  in  pure  condition  most  alkaloids 
can  be  dried  without  decomposition,  in  presence  of  impurities  which 
always  accompany  the  alkaloids  obtained  in  drug  assays,  the  alka- 
loids frequently  become  partially  resinified  when  their  ethereal  or 
chloroformic  solutions  are  distilled  to  dryness  and  are  then  difficultly 
soluble  in  dilute  acids  without  the  use  of  heat.  The  heat  in  presence 
of  free  acid  is  liable  to  injure  many  alkaloids.  In  order  to  avoid  the 
distillation  of  ethereal  solutions  of  alkaloids,  to  dryness,  the  latter 
can  be  directly  shaken  out  with  excess  of  standard  acid  provided 
1  Read  at  the  meeting  of  the  American  Pharmaceutical  Association,  Septem- 
ber, 1906,  and  contributed  by  the  author. 
