Comparison of Sampling Methods for Determination of Pesticide Residue on Leaf Surfaces

摘要

The California Department of Food and Agriculture, Environmental Hazards Assessment Program conducted a study using three methods of obtaining samples for determining surface residue of a pesticide on strawberry foliage. The stability in results relative to the three methods was evaluated between operators collecting samples and between samples collected from separate trials. Trifoliate leaves from strawberry plants, that were sprayed with Captan (50WP), were sampled by collecting one standard leaf punch per sampled leaf (leaf-punch), whole-leaves (whole-leaf), or by wiping both the upper and lower leaf surfaces with gauze moistened with de-ionized water (surface-wipe). Samples were taken by three operators to compare variability in results between individuals and the experiment was repeated in three separate trials conducted 7 days apart to compare the variability in results over time.