COMPARISON OF EXTRACTION HYDROLYSIS PROCEDURES FOR THE DETERMINATION OF ACIDIC HERBICIDES IN PLANTS - RESIDUES OF MECOPROP IN BARLEY FOLLOWING POSTEMERGENCE APPLICATION

Two extraction/hydrolysis procedures for the determination of acidic herbicides in plant tissue were compared for the analysis of mecoprop residues in barley tissue. It was found that organic solvent extraction followed by alkaline hydrolysis was less tedious and time-consuming and provided better recoveries than an extended alkaline extraction/hydrolysis. Following a postemergence application of mecoprop at 1.1 kg ha-1 to barley at the 5-leaf stage, initial residues were on the order of 100 mg kg-1. Six weeks after application, whole plant (above ground) residues had decreased to 0.1-0.2 mg kg-1. At maturity, residues in the straw were < 0.1 mg kg-1, and residues, at the limit of quantification of 0.05 mg kg-1, were not detected in the seed.