How to decrease ion suppression in a multiresidue determination of β-agonists in animal liver and urine by liquid chromatography-mass spectrometry with ion-trap detector

A new liquid chromatography-mass spectrometry with ion-trap detection method for the determination of clenbuterol, ractopamine, clenpenterol, brombuterol, hydroxyclenbuterol, mapenterol and mabuterol in animal liver and urine is described to decrease ion suppression in both matrices. The developed method consists of an aqueous extraction and a two-step clean-up. Final extract was injected in a liquid chromatograph with ion trap mass spectrometer optimized to obtain MS(3) ions which provided more specificity and better signal to noise ratio in the investigated analytes. Those steps have been essential to reach decision limits (CC alpha) values below the proposed MRPL values for each substance. The CC alpha were determined and their values were 0.05 mu g kg(-1) for clenbuterol, 0.2 mu g kg(-1) for ractopamine and 0.1 mu g kg(-1) for the other analytes in liver and the same values in mu g L(-1) for urine samples. (C) 2008 Elsevier B.V. All rights reserved.