EXTRACTION AND CLEANUP OF THE BETA-AGONIST SALBUTAMOL FROM LIVER AND ITS DETERMINATION BY ENZYME-IMMUNOASSAY

A method has been developed for the extraction and immunoassay of salbutamol in liver. The procedure involves digestion of liver with Subtilisin protease at pH 10.5, clarification by acid precipitation and centrifugation. The salbutamol in the supernatant was concentrated onto a 2-g C18 ''Bond Elut'' cartridge at pH 9.1 +/- 0.3, eluted with 99.5% methanol and the eluate concentrated and quantitated by enzyme immunoassay. The method was validated using tissues in which salbutamol had been incurred and tissues spiked with salbutamol. The mean recovery from liver spiked at 1 mug kg-1 was 57 +/- 8% (S.D.). Statistical analysis of the results for 18 batches of samples enabled the calculation of the probability of false negatives (sensitivity) and of false positives (specificity) of the method. The probability of false negatives among samples containing 1 mug kg-1 was 1% and that of false positives was 2.5%. The method was used successfully on incurred tissues, and is used routinely in this laboratory for screening samples taken in compliance with the requirements of the EC Residues Directive (86/469).