A TEST FOR SACCHARIN, AND A SIMPLE METHOD OF DISTINGUISHING 
BETWEEN CUMARIN AND VANILLIN. 
For the recognition of saccharin chemists are dependent upon its 
sweet taste and on the conversion of the compound into salicylic acid 
bv heating with caustic soda- 
Some time ago. while engaged in studying the color of certain of the 
sulphonphthaleins in acid solution, it occurred to me that possibly 
these compounds could be synthesized directly from saccharin with- 
out the previous conversion of this compound into o-sulphobenzoic 
anhydride. 
In order to test the correctness of this idea, small amounts of sac- 
charin were heated with phenol and concentrated sulphuric acid. 
When heated with phenol alone to the boiling point of the latter, no 
change is observable. On the other hand, if a small amount of sul- 
phuric acid is present, the mass takes on a dark purplish-red color 
altogether similar to that obtained when phthalic anhydride, phenol, 
and sulphuric acid are heated in the preparation of phenolphthalein. 
On dissolving the melt in cold water a yellow solution was obtained, 
and on adding caustic soda the solution became deep purplish-red 
in color. Similarly, when small amounts of saccharin, resorcin, and 
sulphuric acid are heated together to 170° C.. the mass becomes deep 
orange yellow in color, and on solution in water and addition of alkali, 
the solution exhibits a strong greenish fluorescence, and bv trans- 
mitted light exhibits the salmon pink color characteristic of sulphon- 
fluorescein. While the opportunity has not yet presented itself for 
the preparation of these compounds on a large scale by this method nor 
for their more careful examination, there is no doubt in my own mind 
that these substances are sulphonphthaleins; and in this connection it 
occurred to me that possibly this reaction could be turned to account 
in the detection of minute quantities of saccharin. 
The reagent employed in carrying out the tests for saccharin given 
in the following consists of a mixture containing 5 cc. of phenol and 
3 cc. of pure concentrated sulphuric acid. When small quantities of 
saccharin are heated with small amounts of this reagent to 160 3 -170~ C. 
for five minutes, and the mass dissolved in a small amount of water 
and rendered alkaline with 2N sodium hydroxide, the solution becomes 
dark purplish red or pink, depending on the amount of saccharin 
originally taken. Any great excess of the reagent is to be avoided, 
( 31 ) 
