LONG-TERM STUDIES OF FUNGICIDE CONCENTRATIONS IN GREENHOUSES .1. TECHNIQUE FOR DETERMINING SURFICIAL FOLIAR RESIDUES OF FUNGICIDES WITH VINCLOZOLIN AND TRIADIMEFON AS MODEL COMPOUNDS

A new analysis procedure for fungicides has been developed gearing toward estimation of worker exposure in greenhouses. The procedure includes sampling on leaves, glass, and polymers using vinclozolin and triadimefon as model substances and starts with solvation of the fungicides with ethanol from the surface. It proceeds by collection of the solution on disks of cloth, disk extraction with excess of ethanol, evaporation of the solution to dryness, and addition of 1-chlorobutane and ends finally with HPLC determination. Validations of the evaporation step, the desorption of analyte from the disks, and the whole procedure were performed separately. The whole procedure gave recoveries of vinclozolin and triadimefon on leaves of 74% (RSD 4.2%) and 79% (RSD 5.0%), respectively, and on hard surfaces around 90% (RSD ca. 6 %) for both substances. The losses in the evaporation and in the desorption step were small, the major losses occurring when the fungicide was collected from the surface. Also, some degradation products of vinclozolin and triadimefon, i.e., 3,5-dichloroaniline, triadimenol, and p-chlorophenol, were briefly studied.