Begtrup (4) pointed out in 1937 that ej.tr-'.ction of derrls or cute 
root '.<;ith a low boiling solvent, such as ether in a So:chl9t apTDaratus, 
is incomplete. On the oth^r hand, he stated that if a r.olvent of higher 
"boiling point is used tie prolonged neating generally destroys the extrac- 
tive substances arid t>>us renders crjfitalli nation of th-^ rotenone difficult 
or impossible. To overccne tcese difficulties h^ reconir-snded extraction 
with toluene at room temperatiare . The procedure suggested "by Pegtrup was 
as follov/s: 
Thirty grsjts of lOO-mesh material is packed in an ordinary 
funnel, thoroughly rcipter.ed with toluene, and v/ashed si::: times 
with 20 cc. of toluene (eac.i extract is per-nitted to drain off 
ccmpl3tely). Tne co-rbined e;:tract is diluted to 150 cc, and a 
50-cc. aliquot iste-ken. Tie tolu^ine is distilled off on an 
oil bath maintained at about 130° C The residue is dissolved in 
7-8 cc. of carbon teti-achlcrice saturated with rotenone at 10° C. 
and transferrsd to a weigrhin^ bottle. Washings bring the total 
volume to 12-15 cc. Cry p.t alii '/--it ion is ailov/'^d to proceed over- 
night at 10° C. Tne cryEvbals are filtered, wc-shed, and dried, 
as in otner methods. 
Chevalier and Chevalier (39) in 1S?7 described a method involving 
extraction wit'a cnlorofcrm and crvstallization from carlcn tetrachloride, 
similar in all essential detai?.s to "Dreviov'-S methods. The rotenone v/as 
purified by recrystalliz.--tion from warm alccnol. 
Ripert (99_) used dichlorcethylene for the -extraction of rotenone. 
The determination of rotenone in samples of I^ erris and Ilundulea 
was described by Guillaure ??jid Froeschel (5;=) in 1937. They used a 
modification of tie method of iCoclhaas (TE^) . Extraction of the 5-gra . 
sample with ether in a continuous percolator was cai-ried out as described 
in the section on Total Sxtrsct. The evaporated extract was then treated 
as follows: 
Add 15 cc. of cold ether to the extract in a tared crystal- 
lizing dish (A), covej, and let stand in the refrigerator for 
about 24 hours. The extract dissolveo and the crystals of 
rotenone deposit. Decant the solvent into a second tared 
crystallizing dish (B) . Hapidly wash the crystals v/ith a 
little cold ether. Lecant the wash liquid into the crystal- 
lizing dish (B) . Keep this dish in refrigerator for 24 hours. 
Dry crystallizing dish (A) in oven at 50° C. for 1 hour and 
weigh. If crystals form in dish (3), decant the liquid, wash 
as before, dry dish and contents at 50° C, weigh and add to 
weight of rotenone in dish (a). 
These investigators attempted to check the sensitivity of the crystal- 
lization method. They added to the powdered root of a species of 
Lebec^tia that contained no roterone 'oy qualitative testr, progressively 
increasin^^• amo^onts of rotenone in the form of carbon tetrachloride sol- 
vate and analyzed the mixtures by the methods indicated. As shown in the 
following tabulation, very good recovery of the rotenone was obtained: 
