Confirmation analysis of clenbuterol in beef liver and minced beef by a combination of immunoaffinity chromatography and liquid chromatography electrospray mass spectrometry or liquid chromatography electrospray tandem mass spectrometry

Confirmation methods based on the combination of immunoaffinity chromatography for sample clean-up and on-line liquid chromatography/mass spectrometry with electrospray ionization in both selected ion monitoring (SIM) and multiple reaction monitoring (MRM) modes were developed for the determination of clenbuterol in beef liver and meat samples, The absolute minimum detection limits are 25 pg per injection (equivalent to 0.18 ng g(-1) of sample) in the SIM mode (using a single mass analyzer) and as low as 3-5 pg per injection (equivalent to 0.02-0.04 ng g(-1) of sample) in the MRM mode (tandem mass spectrometry), Both mass spectrometric methods are compared and the results demonstrate that tandem mass spectrometry offers a much lower detection limit and higher specificity, A beef liver sample and a minced beef sample, both spiked at 1 and 5 ppb levels, were used as examples to demonstrate the excellent sensitivity and specificity of the proposed methods for the unequivocal quantitative determination of clenbuterol in meat products.