i4o 
Lithium  Citrate. 
f Am.  Jour.  Pharm. 
\      March,  1899. 
to  find  that  the  results  were  considerably  below  what  they  should 
have  been  theoretically.  Several  samples  were  then  dried  at  1400  C. 
and  in  every  case  an  additional  amount  of  moisture  was  lost  corre- 
sponding to  differences  indicated  by  the  analytical  results.  Then 
the  moistures  of  all  the  samples  were  carefully  taken,  and  the  results 
obtained  are  recorded  above.  They  were  all  dried  in  the  air-bath 
at  the  same  time. 
The  above  results  were  obtained  from  the  same  material  dried  at 
the  above  temperatures,  from  six  to  eight  hours.  The  amount  of 
water  lost  at  1000  C.  corresponded,  approximately,  to  three  molecules 
of  water  of  crystallization,  when  four  molecules  were  present. 
Not  all  of  the  water  seems  to  have  been  lost  by  drying  at  from 
1 1 5 0  C.  to  1200  C.  for  eight  hours.  This  would  indicate  that  a 
higher  temperature  than  the  above,  is  required  to  completely  dissi- 
pate the  water.  It  may  be  that  a  lower  temperature  than  1400  C. 
will  suffice  to  produce  an  anhydrous  article,  but  the  above  tempera- 
ture is  safe,  and  the  chemical  does  not  seem  to  be  injured. 
A  5  per  cent,  solution,  acidulated  with  acetic  acid,  should  not  be 
affected  by  hydrogen  sulphide,  ammonium  oxalate,  or  sodium  cobal- 
tic  nitrite;  neither  should  ammonium  sulphide  produce  more 
than  a  faint  coloration,  or  silver  nitrate  or  barium  chloride  more 
than  a  faint  opalescence,  when  added  to  the  above  solution. 
The  U.S. P.  method  for  eliminating  an  excess  of  other  alkalies  is 
the  best  obtainable  for  the  present  for  this  salt. 
The  directions  given  for  estimating  the  amount  of  pure  lithium 
citrate  in  this  chemical,  have  not  given  the  writer  satisfactory  re- 
sults. For  comments  on  this  operation  see  this  Journal,  Vol. 
71,  page  61.  Unfortunately,  the  ammonium  sulphate  process 
is  not  applicable.  There  is  such  an  abundance  of  intumescence  that 
the  ammonium  sulphate  does  not  act  well,  and  the  incineration 
becomes  very  tedious. 
The  following  method  gives  good  results:  Weigh  about  0-5 
gramme  of  the  anhydrous,  powdered  salt  into  a  platinum  capsule; 
porcelain  will  answer;  to  this  add,  in  drops  from  a  pipette,  so  as  to 
get  as  complete  a  mixture  as  possible,  about  1  c.c.  of  concentrated 
sulphuric  acid.  Place  the  mixture  on  a  water  bath  a  few  minutes,  so 
that  the  sulphuric  acid  will  thoroughly  permeate  all  of  the  lithium 
citrate.  Now  incinerate.  Apply  the  flame  gradually  at  first,  to 
avoid  spirting.  If  the  work  has  been  well  done,  the  lithium  citrate 
has  been  completely  converted  into  the  sulphate. 
