- 42 - 
These author.^ attempted .to determine "by two schemes the amount of 
rotenone left in the resin after crystallization. The first involved 
extraction of the nonrotenone resins with petroleum ether and cyclohexane 
and crystallization from carbon tetrachloride o: the rotenone in the 
residue, while the second method was "based on adsorption on activated 
fuller's earth and washing cut with benzene, the evapo:'ated residue 
being crystallized from carbon tetrachloride. From a mLnber of samples 
of resin a ran^e of from 4.5 to 17.0 percent (with two exceptions), with 
an average of about 10 percent, of the amount of the original rotenone was 
recovered. 
Results of the anal;' ses of 40 samples of derris root by the authors' 
method and by that of Jones and G-rah?m (72^ were compared. T"ne results 
for piiTe rotenone by the authors' method were in close agreement with those 
for cruJe rotenone oy the latter method. It was found that finer zrinding 
in gen?ja.l resulted in higher values for both rotenone end total ether 
extract. Moi.ier and Koolhaas belie/ed that samples with a ratio of rotenone 
to total extract higher than 40 percent, which v;ere said to be common in 
the Dutch alast Indies, cculd be handled satisfactorily either by finer 
grindin^^ (75 percent through a 200-nesh sieve) or by extraction several 
times with chloroform. They stated that a satisfactory uniform method for 
rotenone might be based on the Jones and Graham method, provided the values 
for crude rotenon? were used and this method was adapted to samples with a 
high ratio of rotenone to total extract. The authors compared results for 
purity of the carbon tetrachloride solvate by polarizat?, on, alcohol recovery, 
and the titration method of Jones (S7). The results were generally in good 
agreement; alcohol recovery in general gave the lowest values, polarization 
highest, and titration between these two. The degree of purity when deter- 
mined by the melting point was said to be generally higher than when deter- 
mined either by polarization or alcohol recovery. As they experienced 
difficulty with the titration method when 20 percent or more impiirity was 
present and as the polarization method was even less time-consuming, the 
authors preferred the latter method. The figures previously given by i'eijer 
(87) to show fne effect on the rotenone content of drying the sample were 
repeated. Keating the sample above 50° C. before analysis was strongly 
discouraged. 
In further work on the evaluation of rotenone-containing plants, 
I'artin (83) in 1940 described the procedure for determining rotenone in 
derris, which involved some modification of previous methods. Sufficient 
root to give about 5 gm. of resin was extracted by hot percolation with 
ethyl acetate for 3 hours in the apparatus already described under methods 
for Total Extract. The resin, freed of solvent, was dissolved in 100 ml. 
of a mixture of benzene and ether (25 percent by volume of benzene) and 
extracted rapidly with 50 ml. of 2-percent potassium hydroxide and then 
with two lots of 5-percent potassium 'tiydroxide. Water was then immediately 
added to the benzene-ether solution to dilute any residual alkali. The 
combined alkaline extract was washed with benzene-ether and the wash added 
to the main solution. The combined benzene-ether solution was then washed 
three times witn water and dried with anhydrous sodium sulfate, and the 
solvent was removed. The resin was dissolved in carbon tetrachloride and 
the rotenone solvate crystallized in the usual way. Determination of tne 
