DETECTION AND CONFIRMATION OF BETA-AGONISTS IN BOVINE RETINA USING LCAPCI-MS/

beta-Adrenergic receptor agonists are growth-promoting drugs with the potential far illegal use in livestock, and human toxicity has resulte d from consumption of contaminated meat, On-line liquid chromatography with atmospheric pressure chemical ionization mass spectrometry (LC/A PCI-MS) was used for sensitive detection of several beta-agonists in r etina, a tissue reported to concentrate and retain such residues for e xtended periods, Multiresidue extraction, separation, detection, and c onfirmation procedures were developed for retinal tissue and applied t o eyes from cattle treated with clenbuterol (69-201 ppb) and to contro l eyes spiked with salbutamol (100 ppb) and terbutaline (25-100 ppb). Rapid switching of the potential difference between sampling tone and skimmer in the transport region of the API source was used to optimize acquisition of the protonated molecules and characteristic fragment i ons obtained by collision-induced dissociation reactions. The respecti ve selected ions were simultaneously acquired using a single quadrupol e mass spectrometer. The accurate and precise agreement observed for d iagnostic ion intensity ratios between beta-agonists in retinal sample s and authentic standards suggests that LC/APCI-MS can he used for con firmation of analyte structure at trace levels and does not require th e use of a triple-stage quadrupole mass analyzer.