Superheated water extraction and phase transfer methylation of phenoxy acid herbicides from solid matrices

Phase transfer catalytic methylation was applied to directly derivatise chlorophenoxy acid herbicides in superheated water extracts from sand and soil samples. The extractions were carried out at 120 ◦C statically for 5 min and then dynamically for 10 min at 1.0mLmin−1 using water at pH 11.0 for a sand matrix and a flow rate of 0.5mLmin−1 at pH 7.0 for soil samples.