Current clean-up procedures for the determination of beta-agonists in bovine urine by enzyme immuno assay (EIA)

beta-Agonists are suspected to be illegaly used as growth promotors. EIA is an important tool to screen such substances in urine samples of cattle in life stock. Here the sample clean-up is of importance. This work reports the results of several clean-up procedures: immunoaffinity chromatography (IAC) on a commercial reusable IAC column, two different solid phase extraction (SPE) methods and a fast method with simple dilution of the urine samples. The IAC, first designed for confirmation analysis like GC-MS, delivers very clean extracts but, compared with SPE, is expensive, time consuming and not universally usable. SPE shows sufficient clean extracts and can be simply automated. Finally is shown, that the simple dilution of urine samples is enough sensitive to screen samples with high concentrations of beta-agonists.