INFLUENCE OF SOLVENT AND STORAGE-CONDITIONS ON THE STABILITY OF ACARICIDE STANDARD STOCK SOLUTIONS

The stability of bromopropylate, coumaphos, amitraz and chlordimeform stock solutions in methanol and in n-hexane and the incidence of stora ge conditions have been studied using GC-MS. It has been found that th e initial concentrations have a progressive depletion from the startin g time, this fact is more important when methanolic solutions are stor ed at room temperature. Several degradation products have been detecte d and identified, their concentration has been rising during storage t ime. A lifetime for the stock solutions should be established on the b asis of their diminishing concentration percentages in order to avoid further errors in quantitative analysis, below the limit the solutions should be changed for new ones.