504 
Commercial  Iodide  of  Potassium. 
i  Am.  Jour.  Pharm. 
t       Oct.,  1883. 
well  as  the  average  of  the  European  samples,  and  a  little  better  than 
one  of  them.  I  do  not  present  the  results  of  tests  of  these  few  samples 
alone,  as  giving  conclusive  answer  to  the  latter  clause  of  the  query,  or 
full  answer  to  the  first  clause  of  it.  But  I  have  no  information  to 
oppose  to  the  bearing  of  these  few  examinations,  and  have  had  a  little 
experience,  before  mentioned,  going  to  support  the  results  here  found. 
Therefore  I  believe  it  will  be  found  that  a  buyer  must  exercise  some 
selection  in  lots  in  order  to  obtain  the  medicinal  salt  of  this  country  in 
as  good  a  degree  of  purity  as  the  average  imported  pharmacopceial 
article. 
(1)  For  lodate: 
U.  S.  Ph.  test,  solution 
1  to  20,  with  starch... 
Solution  i  to  4,  with 
S  tH>l'Cll  
Solution  i  to  20,  acid, 
without  starcli  
No.  1.  No.  2. 
No  color        Purple- blue 
Purplish  'pale  blue  
Slight  yel'w  Pale  yellow. 
Result. 
Comparison  as  to  io- 
date  (1  best)  
{'I)  For  Alkali: 
U.  S.  Ph.  test,  wet  lit- 
mus paper  
Solution  of  1  to 2,  with 
lime  water  
Volumetric  estimation 
of  K2CO3  
Result  
(3)  For  Chloride  and 
Bromide : 
U.  S.  Ph.  test  
Standard. 
3 
.  Hardly  up  to 
I  standard... 
Test  for  bromine. 
Resxdt  
Comparison  
Deep  blue....  Deep  blue.... 
Precipitate..  Precipitate.. 
0-74  per  cent.  1-84  per  cent 
Below  stand. !  Below  stand 
Precipitate  |Prec. atonce 
at  once. 
Present  \  Presen  t.. .. 
Not  standard  \Not  standard 
3  4 
(4)  For  Sulphate  : 
U.  S.  Ph.  test  (adding 
hydrochloric  acid)  
Result  
Comparison 
(5)  For  Cyanide . 
Ph.  Germ.  test- 
Cloudy  in  5  Prec. atonce 
min.  I 
Not  quite      \Not  standard 
standard . 
No.  3. 
No  color.. 
Purplish.. 
No  color  . 
Standard. 
1 
Violet-blue. 
No  precip.... 
0*05  per  cent 
Standard  
Srt  cloudi- 
n's  at  once 
Present  
Not  stand'' rd 
1 
No.  4. 
No  color  . 
Purplish.... 
Pale  straw 
color  
Standard  
2 
Faint  blue- 
No  precip. . - 
1 0*24  per  cent. 
Hardly  up  to 
i    standard ... 
srt  cloudi- 
n's  at  once 
Present  
Not  standard 
2 
No.  5. 
No  color. 
Purplish. 
No  color. 
Standards 
1 
Violet-blue. 
No  precip. 
0-04  percent. 
Standard. 
Cloudiness 
at  once. 
Absent. 
Not  standard 
1 
(6)  For  Sodium  Salt  : 
Ph.  Germ,  test,  flame 
color  
U.  S.  Ph.  identification 
of  potassium  
(7)  For  Moisture  : 
Loss  at  2120F.  (100°C.)  ... 
(8)  For  Free  Iodine  : 
The  solution  with  car- 
No  cyanide. 
No  cyanide- 
Yellow   Yellow  
Potassium. .  Potassium. 
bon  disulphide. 
(9)  For  Nitrate:  In  fil- 
trate from  silver  pre- 
cipitate  
(10)  Sensible  Proper- 
ties :  Color  
Odor  
1-4  per  cent. 
None. 
None. 
White  
Dist'ctodor. 
1-3  per  cent. 
Prec.  at  once 
Not  standard 
5  1 
Cloudy  in  5  Clear, 
min.. 
Nearly  stan- 
dard. 
No  cyanide.  No  cyanide. 
Yellow  
Potassium... 
0-6  per  cent.. 
None. 
None. 
White.... 
No  odor. 
None. 
None. 
White  
Faint  odor. 
Violet  
Potassium... 
0*8  per  cent., 
Standard. 
1 
None. 
None.. 
White  
Faint  odor... 
No  cyanide. 
Yellow. 
Potassium. 
0*4  per  cent. 
None. 
None. 
White. 
No  odor. 
