Multi-residue analysis of anabolics in calf urine using high-performance liquid chromatography with diode-array detection

We describe the development of an HPLC method with diode-array detection (D AD) for the analysis and identification of 20 substances with anabolic prop erties, that are considered as potential growth promoters, to be used for t he analysis of extracts of calf urine samples. The substances are separated on an RP-Select B column using a mobile phase consisting of a mixture of a cetonitrile and water. Gradient elution from 43-76% acetonitrile in water w ith a concave curve was used to achieve a good separation of the compounds with an acceptable analysis lime. For the identification, a retention param eter and the UV spectrum were used. The retention parameter was the retenti on time corrected with a reference mixture. The latter reduced the standard deviations to about 25% of their original values. The limits of detection of the HPLC system ranged from 0.5-5 ng injected amount for the androgens, progestagens, stilbenes and resorcylic acid lactones and to 5-10 ng injecte d amount for the oestrogens. After extraction from urine the limits of dete ction were increased by the presence of matrix components, but they were be tween 5 and 10 ng injected amount for most of the substances. (C) 1999 Else vier Science B.V. All rights reserved.