EXTRACTION AND ASSAY OF AGROCHEMICALS IN ACRYLIC ANTIFUNGAL FORMULATIONS BY TLG-DENSITOMETRY

A method combining extraction and assay has been developed for two fun gicidal agents, thiram (tetramethyl dithiocarbamoyl disulfide) [137-30 -4] and thiophanate-methyl [23564-05-8], and a growth hormone: 3-indol ebutyric acid (IBA) [133-32-4], contained in acrylic matrices (liquid or solid). Formulations of this type are employed for topical applicat ion to tree wounds. Dichloromethane was employed for liquid - liquid e xtraction and a mixture of dichloromethane and carbon tetrachloride (1 :1, vlv) for solid - liquid extraction. One-dimensional TLC was perfor med on silica gel plates eluted with n-hexane - ethyl acetate - aceton e (4 + 4 + 1). The compounds were quantified by densitometry (254 nm), using either p-hydroxyacetanilide or propiophenone as internal standa rd. This method has application for the quality control of active prin ciples after formulation, for checking long-term stability, and for ev aluation of the persistence of antifungal action after application. Th is method may also find application for assay of fungicides and other protective agents in acrylic-and vinyl-based paints.