Abstract: Anti-terbutryne mAb were immobilized to polystyrene and glass beads, and the different immobilization techniques were compared for their applicability in FIA. The immobilization methods used were (i) covalent immobilization to glass beads using acetic acid/periodate with subsequent coupling of biotinylated antibodies; (ii) adsorption of avidin to polystyrene beads and coupling of biotinylated antibodies and (iii) covalent immobilization of antibodies to glass beads with glutaraldehyde. Methods (ii) and (iii) were the most effective, and (iii) was found most effective for FIA. The antibodies could be regenerated at least 60 times. The calibration graph was linear from 0.01 µgl (detection limit) to 5 µg/l. The method could be used for monitoring drinking water sources.