66 
Schmitt ( l09 ) in 1930 stpted that rotenone may be detected in ground 
root "by treatment vrith nitric acid, v;hereapon the affected portions turned 
red. 
Pozzi-~scot (95) in 1936 stated that rotenone dissolved in concentrated 
sulfuric acid with the formation of a red-cerise or rose- cerise coIoj:. When 
the acid contained mercuric oxide in solution, as in Denige's reagent, the 
color reaction vrith rotenone was from 100 to 1,000 times more sensitive and 
was not subject to interft;rence from as many other substances as vrhen acid 
alone was used. On being warmed with this reagent, the rotenone disBolved 
giving an intense orange-yellow color. The intensity of color t\'as observed 
to be proportional to the amount of rotenone. 
In later work Pozzi-iscot (98 ) discussed the color reactions given by 
sulfuric acid, sulfuric and nitric acids, and Denige's reagent ^^dth sub- 
stances that might interfere with the rotenone reaction, and described methods 
for differentiating between the reaction of rotenone and reactions of other 
substances. 
In 1937 Tapia Treses ( ll9 ) reported that rotenone gave a red-violet 
color with a solution containing 0.1 gm. of van?»dium pentoxide in 10 cc 
of sulfuric acid. 
OTHSH T)ETIHMINATIO!TS 
Polarimetric Methods 
Danckwortt and Budde (?4) in 1933 stated that polarim?tric determinat- 
ions might ultimately be used for the evaluation of derris root. 
In the same year Jones (62) briefly studied the possibility of using 
the high optical rotation of rotenone (74) (in benzene [alpha]r^= ^24° for 
a 5-percent solution) as a means for its determination. The optical 
rotatory powers of derris and cube extracts were det'^rmined in several 
solvents, and a hypothetical rotenone content was calculated from the values 
for pure rotenone. In most cases the results v;^.^re very much higher than 
those obtained by crystallization. Since one derris extract was dextrorotat- 
ory, it was concluded that optical rotation cannot be used as a measure of 
the amount of rotenone present in the root. 
A polarimetric method proposed by Danckwortt, Eudde, and Baumgarten 
(25) in 1934 was claimed to be superior to the crystallization methods, at 
least as a measure of the toxicity of derris. Directions were as follows: 
3 gm. of finely pulverized sample is digested with 30 cc. 
of benzene at room temperature for ?4 hours. The optical 
rotation of the filtered benzene solution is determined in a 
100-mm. tube. Tae rotenone content is obtained by the follow- 
ing formula: 
Percent rotenone - alp^ui X 1.000 
233 
In 10 out of 11 samples of derris root the method gave values higher 
than those by cr^'stallization. The method was also adapted to the deter- 
