Glycyrrhizin  in  Licorice  Root. 
5  Am.  Jour.  Pharni. 
X      June,  1921. 
The  insoluble  residue  on  the  filter,  I  dissolved  in  ammonia  and 
evaporated  in  a  weighed  crucible.  The  weight  varied  between  0.09 
to  0.1 1  g.  There  is  therefore  0.9  to  1.1  per  cent,  weighed!  as  ammo- 
niated  glycyrrhizin,  which  only  consist  of  impurity  in  the  acid.  The 
ammoniated  glycyrrhizin,  obtained  by  Diehl's  method  is  of  a  much 
lighter  color  than  that  from  other  methods.  The  difference  is  very 
noticeable.  It  is  remarkable  in  this  determination,  that  Diehl  does 
not  simply  weigh  the  alcoholic  solution  of  glycyrrhizic  acid  which  he 
evaporates  to  dryness.  Instead  of  that,  he  dissolves  the  dry  residue 
again  in  ammonia,  transfers  to  a  tared  dish,  and  weighs  after  drying 
again.  This  unnecessary,  roundabout  way  results  in  much  loss  of 
time,  and  only  renders  errors  possible.  I  obtained  from  10  g.  licorice 
8.24-8.44  per  cent.  As  losses,  I  obtained  1.91-2.11  per  cent.  The 
insoluble  matter  was  39-40  per  cent,  of  the  licorice  taken. 
The  method  of  Diehl,  in  the  form  given,  cannot  be  used  on  ac- 
count of  such  vagueness.  If,  however,  the  missing  instructions  are 
intelligently  completed,  and  one  omits  the  useless  conversion  of  the 
dried  acid  to  the  ammonium  salt,  one  obtains  good  results,  and  a 
precipitated  acid  of  a  high  degree  of  purity. 
6.  Kremel  (1899). 
"For  the  estimation  of  glycyrrhizin,  5  g.  of  roughly-broken  lico- 
rice extract  are  dissolved  in  50  cc.  water,  and  allowed  to  stand  sev- 
eral hours  with  frequent  stirring.  After  disintegration,  50  cc.  of  90 
per  cent,  alcohol  are  added,  stirred,  the  mixture  allowed  to  settle, 
and  filtered  through  a  small  fluted  filter.  The  contents  of  the  filter 
are  thoroughly  washed  with  40  per  cent,  alcohol.  The  alcohol  is 
evaporated  from  the  filtrate  on  the  water  bath.  After  cooling,  sul- 
phuric acid  is  added  to  precipitate  the  glycyrrhizin.  This  is  collected 
on  a  small  filter,  well  washed  with  distilled  water,  and  finally  brought 
into  solution  by  dropping  ammonia  on  the  filter.  The  ammoniated 
glycyrrhizin  is  collected  in  a  dish,  evaporated  to  dryness  on  a  water 
bath,  dried  at  ioo°  and  weighed." 
Kremel's  method  is  inexact  in  some  details,  so  that  compara- 
tive values  cannot  be  directly  obtained  from  it.  It  is  not  stated  how 
much  alcohol  is  used  to  wash  the  insoluble  matter.  I  found  50  cc. 
yielded  a  nearly  colorless  filtrate. 
[Translator's  Note. — Other  sources  of  error  due  to  vagueness 
are  mentioned,  including  failure  to  specify  quantity  of  sulphuric 
acid  and  of  water  used  for  washing  the  precipitate.  (P.  A.  H.)] 
