An immunoaffinity solid-phase-extraction sorbent has been developed by raising polyclonal antibodies against propanil and covalently bonding them to activated silica. This immunosorbent (IS) had high affinity for propanil and for structurally related phenylurea herbicides whereas structurally related chloroanilines were retained only poorly. Studies of breakthrough volumes, capacity, and calibration ranges of selected pesticides showed that the antibodies have different affinities for each compound. Propanil and phenylureas could be quantitatively recovered by elution with methanol–water; average recoveries were close to 100%. The IS was also packed in a precolumn and coupled on-line to HPLC–UV. The high selectivity provided by the IS was demonstrated by comparing results with those obtained by use of a non-selective polymeric sorbent when both were used for direct extraction of propanil and phenylureas from a 50-mL sample of river-Seine water spiked at 0.1 µg L–1 or from lemon juice spiked at 50 µg L–1.
