Development of a readily applied method to quantify ractopamine residue in meat and bone meal by QuEChERS-LC-MS/MS.

A QuEChERS method of ractopamine (RCT) residue detection in swine meat and bone meal (MBM) samples was demonstrated. Samples were hydrolyzed with protease and β-glucuronidase prior to QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction and clean-up. Samples were analyzed in a Liquid Chromatography (equipped with ACE 5 C18 column under gradient elution) coupled with a triple quadrupole mass spectrometer operating in positive electrospray ionization mode (using multiple reaction monitoring, MRM). The method was validated for its specificity, decision limit (CCα), detection capability (CCβ), recovery, repeatability, reproducibility, linearity, limits of detection (LODs), quantification (LOQs), and stability according to international guidelines (European Commission Decision 2002/657/EC). Recoveries ranged from 96.3 to 107.0%. Repeatability and reproducibility showed both RSD<5.7% and 3.1%, respectively. LODs and LOQs were 1.91 and 6.36 ppb, respectively. CCα and CCβ values were 1.91 and 2.37 ppb, respectively. RCT showed good stability for spiked samples and real samples when the concentration was higher, otherwise at lower concentration stability was lower. The proposed method can be successfully applied on a regular basis for the determination of RCT in MBM, demonstrating the usefulness of the method as a tool for compliance monitoring in regulatory laboratories.