Determination of macrolides in animal tissues and egg by multi-walled carbon nanotube-based dispersive solid-phase extraction and ultra-high performance liquid chromatography-tandem mass spectrometry.

A simple and reliable analytical method was developed for the simultaneous determination of 11 macrolides in swine, chicken, bovine, and sheep tissues (muscle, liver, kidney, and fat), as well as eggs. Samples were extracted using a mixture of acetonitrile, ethyl acetate, and methanol; dispersive solid-phase extraction purification was then performed using multi-walled carbon nanotubes as the sorbent. The analytes were separated through ultra-high performance liquid chromatography and detected by electrospray ionization on a triple quadrupole mass spectrometer. The average recoveries ranged from 83.5% to 111.4%; the corresponding intra-day and inter-day relative standard deviations were less than 13.6% and 16.4%, respectively. The limit of detection and quantification of the eggs were 0.1-0.6 and 2.0 μg/kg, respectively. For other tissues, the limits of detection and quantification were 0.1-2.0 μg/kg and 5.0 μg/kg, respectively. The proposed method was successfully employed for the analysis of real samples to demonstrate its applicability.