- ?5 - 
Seaber (ll_2_) in' 1938 putlifhe.^ results' of analyses of derris, timbo, 
barbasco, and cubs 'roots by the room tempdratiire-chloroform-aliquot extrac- 
tion method of Beach (3) and the short-time (6 hours) carbon tetrachloride 
Soxhlet extraction of S3il (see p. 25). The first method almost invariably 
gave higher results for (""erris and generally lower results for timbo and 
barbasco, while results for cube v;6re only a little hi^^her by the first 
method. It was suggostec' tliat derris roots be a-jsayed by the room tempera- 
ture-chloroform method, v;hile other roots be analyzed by both methods and 
the higher result taken. As in previous work, Seaber determined the piiri ty 
of th'3 solvate by polarisation. 
The following method for the isolation of small quantities of 
rotenone from oleaf^lnous seeds v;as described oy G-ui chard (52) in 1938: 
TTie saraole is extracted in the cold wif": ether or petrolerjn 
ether. After evaporation of the solvent the oily liquid is 
extracted with 50-percent aceti'3 acid in a separatory funnel 
until the last lot £:ives no color reaction for rotenone. This 
acid solution is extracted with ether and t-is 3th?r evaporated. 
The residue is dissolved in aboj.t 10 oc. of 50-percent acetic 
acid, and the solution is filt'3:.'6d end dried under vacuum until 
all the acetic acid is removed.. Tnis :"esidu;? is dissolved in 
several cubic centimeters of ether and placed in a partly covered 
weighing bottle in the refrigerator for 2 v.-eeks to cryptallire. 
If crystalli7ation does not occur in this tine, tho solution is 
evaporated and the residue, dissolved in 4 to 5 cc of 50-percent 
acetic acid, is filtered and dried as before. This residue is 
now dissolved in 2 to 3 cc . of anhydrous ether and left in the 
refrigera^tor as' before for 2 weeks, wlien crystallisation has 
occurred the ether solution is decanted, the crystals are 
dissolved in cold anhydrous ether, and this solution is replaced 
for crystalli-^ation as before. By such successive crystallisa- 
tions as this pure rotenone is obtained. 
The determination of rotenone was discussed by Koolhaas and I.'eijer 
(79) in 1938. Not only was some rotenone left uncrystallized but varying 
amounts remained in the mother liquor. As an extreme case, that of a root 
with a total-extract content of 25 percent a,nd an a>.ctual rotenone content 
of 3 percent, rotenone amountini-r to 2.2 percent might be left in the 
mother liquor. In a root of this type by the usual method only about 60 
percent of the true rotenone content would be obtained. 
AJethods for determining rotenone were discussed at length by 
Bertaud-E-ossi (6) in 1938. The method of Jones (o^) was said to give 
satisfactory results, but several changes designed to give more rapid 
results were introduced. To obtain ready crystallization of the rotenone 
from carbon tetracnloride , the extract should be dry. Iiather than dry 
the sample itself end thus ca.use decomposition of the rotenone, this in- 
vestigator dried the carbon tetrachloride extract over anhydrous sodium 
sulfate. The time of crystallization varied with the proportion of rotenone 
to resin; crystallization took place rapidly in extracts rich in- resin. A 
device for enclosing the filtering crucible in an ice bath to maintain the 
