Comparison of immunoaffinity chromatography combined with gas chromatography-negative ion chemical ionisation mass spectrometry and radioimmunoassay for screening dexamethasone in equine urine.

A comparison of the sensitive analytical methods of radioimmunoassay (RIA) and immunoaffinity chromatography (IAC) combined with gas chromatography-negative ion chemical ionisation mass spectrometry for the specific and reliable screening of dexamethasone in equine post-race urine is presented. Results from analyses of samples collected from a mare during 144 hours post administration of 26 mg of dexamethasone sodium phosphate are described.