The assay of‘pyrethrin’ and allethrin concentrates with 2 : 4‐Dinitrophenylhydrazine

摘要

AbstractA new technique for the assay of‘pyrethrins’ and allethrin, based upon the reaction with 2 : 4‐dinitrophenylhydrazine, is described. Comparative assays on a series of standards and concentrates indicate that the new method is consistent and accurate, but that the A.O.A.C. (Association of Official Agricultural Chemists) method gives seriously high re