April, 1944
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ANALYTICAL EDITION
Some Color Tests for Rotenone Not Specific H. L. HALLER
U. S. Department of Agriculture,
Bureau of Entomology and Plant Quarantine, Belbville, Md.
0
F THE several colorimetric tests proposed for the detection of rotenone (9), the blue color, or Durham, test (4) and the red color, or Grossdmith-Goodhue, test (6, 6) have been found especially useful. The Durham test is based on the observation that when rotenone is treat& with nitric acid and then with ammonia an evanescent blue calor is produced; i t has been modified by Jones and Smith ( 2 2 ) to make it more delicate and suitable for general use. I n the Grass-Smith-Goodhue test B red color is obtained when an alooholic potassium hydroxide solution containing sodium nitrite is added to rotenone and the mixture subsequently is acidified with SUlfUriC acid. Either test o m be relied upon to show the presence of rotenone or some of the rotenoids (IS) in spcimens of Derris, Lonchocarpus, and Tephrosia. The blue color test has h e n used by Jones et 01. (10) and by Sievers and associates (14) to select specimens of devil's-shoestring (TephTosia uirginiana) highest in rotenone content. Jones et al. ( I O ) found that the effectiveness against houseflies of acetone extracts of various species of Tephmsia is well correlated with the degrx of blue or blue-green color given by the Durham test. By this simple test the effectiveness of a sample of Tephroaia can be roughly predicted. Likewise, the red color test has been widely used in the quantitative evaluation of material containing rotenone and some of the rotenoids. Cahn et al. (8)found the method useful in an extensive study of the composition of derris root. These c a l x tests, however, are not always specific for rotenone in other genera of Leguminosae. For example, in 1937 Moore ( I Z ) ) , searching for a domestic source of rotenone. reported its presenoe in Amrpha fmticosa because i t gave a positive Durham test. Subsequently Fatherly (21, of Oklahoma Agricultural and Mechanical College, confirmed the observations of Moore and proposed that seed of the plant he used as a source of rotenone during the war emergency. More recently, however, Aeree, Jacobson, and Haller ( I )have shown that rotenone is not present in the seeds of A. frulicosa and that the blue color is produoed by a glycoside whose value as an insecticide remains to be determined. The yam bean (Pachyrhizus eiosus) also was reported to contain rotenone solely on the hasis of the Durham test (8). Both this plant and Amrpha jmticosa give a positive red color test. Certain synthetic organic compounds have also been shown to produce an evanescent blue color when the Durham test is rtpplied (7). From the foregoing results i t appears that considerable oautiou should be taken in interpreting the color obtained in both these tests when they are applied to plant materid other than Derris, h b c n r p u s , and Tephrosia. Rotenone should be reported as present in plants only when i t has been definitely isolated and characterized. LITERATURE CITED
(1) Acree, F.. Jr., Jaoobson, M., and Hitller. H. L., J . Am. C h a .
Soc., in press; Science, in press. (2) Agrioultural Insectioide and Fungicide Assoc., Bull. D23 (Oct. 7,1942). (3) Cahn; R. S.. Phipers, R. F., and Born, J. J., J. Soc. Chem. Ind. 57, 200 (1938). (4) Gimlette, J. D.,"Malay Poisons and Charm Cures", 2nd ed., p. 221,London, J. and A. Churehill, 1923. (5) Goodhue, L. D., J . Assoo. Oficial Agr. C h a . , 19, 118 (1936). (6) Gross, C. R.,and Smith, C. M., Ibid., 17: 336 (1934). (7) Harper. S.H.. J. C h a . Soc., 1942,595. (8) Hwang, S.-L., Kwangsi Agr.. 2 (4).269 (1941). (9) Jones, H. A,, U. S.Bur:Entomol. Plant Quer..Bull. ES63 (1942).
(10) Jones. H.A., Campbell.F. L.. and Sullivan, W.N., Soap. 11 (9) 99 (1935). (11) Jones. A. A.. and Smith, C.M., Im. ENQ.CHSX..ANAL. ED.,5, 75 (1933). (12) Moore. R. H..PuertoRiooEapt. Sta. Rept.. 1937. (13) Roark, R. C..J . E m . E n t m l . , 33,416(1940). (14) Sievers, A. F., Russell, G. A,, L o m a n , M. S.. Fowler, E. D.. Erlanaon. C . O., and Little, V. A,. U. S. Dept. Agr.. Tech.Bull. 595 (1938).
Washing Selas Filtering Crucibles by Reverse Flow ERWIN
J. BENNE
Michigan Agricultural Experiment Station, bst Lansing, Mich.
S
INCE it has become impossible to obtain asbestos forandytical filtrations as desirable as that formerly available, the author and his associates have sought equally effective and convenient means of quantitative filtration without the use of asbestos. Selas filtering crucibles meet these requirements for certain determinations, including potassium by the chloraplatinate method, sugar by use of Fehling's solution, and others. These crucibles are similar to the Gooch type in shape but have a k e d , porous bottom for the filtering element, thereby eliminating the use of asbestos. Directions for cleaning recommend washing with hot water or hot acids by reverse flow in order to remove fine, insoluble particles lodged in the pores of the upper surface of the filter, hut do not suggest a convenient, mechanical means of accomplishing this; hence, the author devised the ar-
