Simplified Method to Measure Suspensibility of Water-Dispersible Powder: Use of Microanalytical Techniques to Reduce Wastewater

Abstract

Abstract A method was developed for suspensibility of pesticides in the form of water-dispersible powders (WPs) as an alternative to CIPAC method MT 15.1. After the suspensibility study, the methods, along with several variations, were compared on the basis of reduction of waste, simplicity of the procedures used, and time required to measure suspensibility. WPs in this study were prepared by using fenitrothion and procymidone as representatives of liquid and solid active ingredients. The best method was obtained by modifying CIPAC MT 15.1 as follows: (a) A100 mL measuring cylinder was used instead of a 250 mL cylinder, (b) the process for preparing a suspension in a beaker was deleted, (c) the content of the active ingredient in the top 90% was analyzed instead of the bottom 10%, and (d) the process for evaporating water from a suspension removed by pipet from the top 90% was deleted. Suspensibility determined by this method showed good consistency with that determined by the original CIPAC method, and results were reproducible. Time required for determination of suspensibility and the amount of waste produced by this method was about 40% of that for the original CIPAC method. Furthermore, this method is suitable for WPs made with both liquid and solid active ingredients.