Determination of ractopamine in pig hair using liquid chromatography with tandem mass spectrometric detection

A quantitative analytical procedure for the determination of ractopamine in pig hair has been developed and validated. The hair samples were washed and incubated at 75 degrees C with isoxuprine and hair extraction buffer. The drug present was quantified using mixed solid-phase extraction and liquid chromatography with tandem mass spectrometric detection. The limit of quantization (LOQ) was 10 pg/mg and the intra-day precision at 25 pg/mg and 750 pg/mg was 0.49% and 2.8% respectively. Inter-day precision was 0.88% and 3.52% at the same concentrations. The hair extraction percentage recovery at 25 pg/mg and 50 ng/mL was 99.47% and 103.83% respectively. The extraction percentage recovery at 25 pg/mg and 50 ng/mg was 93.52% and 100.26% respectively. Our results showed that ractopamine residues persist in hair in 24 days of withdrawal and also showed the possibility to test ractopamine from pig hair samples. (C) 2014 Elsevier Inc. All rights reserved.