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Color test for rotenone
Feb., I933.]
CURRENT TOPICS.
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gram in the entire body sufficed to produce in the rat a definite polycythemia or excess of red corpuscles in the blood. Cobalt was not found in the tissues of pigs fed the basal ration, but definite quantities of cobalt were present in the tissues of pigs fed a similar ration plus cobalt salt. J. S. H.
Decomposition of Mineral Otis by Sunlight.--L. W. GREEN AND R. E. SCHOETZOW (]our. Am. Pharm. Asso., i932, xxi, I286---I287) report that mineral oil (heavy liquid petrolatum, U. S. P.), bottled in flint glass, and exposed to the sunlight, may develop a disagreeable odor and taste. The rate of spoilage depends on the geographical source of the crude oil. The stability of such oil may be ascertained by bottling in flint glass, and then exposing to ultraviolet light for comparatively short periods of time (3 to 49 hours). J. S. H. Color Test for R0tenone.--HOWARD A. JONES AND CHARLESM. SMITH (Ind. & Eng. Chem., Analytical Edition, 1933, v, 75-76) described the following color reaction of the insecticide rotenone. The test will reveal the presence of as little as o.I milligram of rotenone. Mix I cc. of the acetone solution of rotenone with I cc. of dilute (I to I) nitric acid, and let stand 30 seconds. Then dilute with 8 or 9 cc. of water, and add I cc. of concentrated ammonia water. A blue color is obtained, almost identical with that yielded by bromothymol blue at pH 7.2. The insecticide deguelin, which, like rotenone, is of vegetable origin, also gives this reaction. J. S. H.
New Reagent for Zinc.--ARMAND J. QUICK(Ind. &Eng. Chem., Analytical Edition, 1933, v, 26) recommends borneolglycuronic acid as a reagent for zinc. A 5 per cent. aqueous solution of this acid forms a characteristic crystalline precipitate, (C16H,5OT),Zn.2H,O, when added to a solution containing as little as 0.03 per cent. of zinc in solution. The crystals are white and glistening. The precipitate may be weighed; or it may be hydrolyzed by boiling with normal hydrochloric acid for 15 minutes, and the liberated glycuronic acid then be determined by any of the common sugar methods. Of the common metals, only cadmium behaves in a similar manner. J. S. H. Sodium-Lead All0y.--CHARLES W. STILLWELLAND WALTER K. ROBINSON (Jour. Am. Chem. Sot., 1933, lv, I27-I29) have applied
CURRENT TOPICS.
235
gram in the entire body sufficed to produce in the rat a definite polycythemia or excess of red corpuscles in the blood. Cobalt was not found in the tissues of pigs fed the basal ration, but definite quantities of cobalt were present in the tissues of pigs fed a similar ration plus cobalt salt. J. S. H.
Decomposition of Mineral Otis by Sunlight.--L. W. GREEN AND R. E. SCHOETZOW (]our. Am. Pharm. Asso., i932, xxi, I286---I287) report that mineral oil (heavy liquid petrolatum, U. S. P.), bottled in flint glass, and exposed to the sunlight, may develop a disagreeable odor and taste. The rate of spoilage depends on the geographical source of the crude oil. The stability of such oil may be ascertained by bottling in flint glass, and then exposing to ultraviolet light for comparatively short periods of time (3 to 49 hours). J. S. H. Color Test for R0tenone.--HOWARD A. JONES AND CHARLESM. SMITH (Ind. & Eng. Chem., Analytical Edition, 1933, v, 75-76) described the following color reaction of the insecticide rotenone. The test will reveal the presence of as little as o.I milligram of rotenone. Mix I cc. of the acetone solution of rotenone with I cc. of dilute (I to I) nitric acid, and let stand 30 seconds. Then dilute with 8 or 9 cc. of water, and add I cc. of concentrated ammonia water. A blue color is obtained, almost identical with that yielded by bromothymol blue at pH 7.2. The insecticide deguelin, which, like rotenone, is of vegetable origin, also gives this reaction. J. S. H.
New Reagent for Zinc.--ARMAND J. QUICK(Ind. &Eng. Chem., Analytical Edition, 1933, v, 26) recommends borneolglycuronic acid as a reagent for zinc. A 5 per cent. aqueous solution of this acid forms a characteristic crystalline precipitate, (C16H,5OT),Zn.2H,O, when added to a solution containing as little as 0.03 per cent. of zinc in solution. The crystals are white and glistening. The precipitate may be weighed; or it may be hydrolyzed by boiling with normal hydrochloric acid for 15 minutes, and the liberated glycuronic acid then be determined by any of the common sugar methods. Of the common metals, only cadmium behaves in a similar manner. J. S. H. Sodium-Lead All0y.--CHARLES W. STILLWELLAND WALTER K. ROBINSON (Jour. Am. Chem. Sot., 1933, lv, I27-I29) have applied