Evaluation of two modified quick, easy, cheap, effective, rugged and safe (QuEChERS) sample preparation methods for the analysis of baclofen and gabapentin in feeds by liquid chromatography tandem mass spectrometry.

This paper presents a new analytical method for the simultaneous determination of baclofen and gabapentin in feeds based on two modified quick, easy, cheap, effective, rugged and safe (QuEChERS) sample preparation methods and liquid chromatography tandem mass spectrometry (LC-MS/MS). For the two modified QuEChERS methods, samples were first extracted with acidified acetonitrile (5.0% acetic acid, v/v) without using acetonitrile salting-out extraction. Then, the first modified QuEChERS method was established according to the original QuEChERS cleanup procedure. For the second modified QuEChERS method, the extract was evaporated to dryness and reconstituted in acetonitrile. Subsequently, the analytes in the reconstituted solution were retained by primary secondary amine (PSA) and released from PSA with 1.0% formic acid in methanol. Finally, the eluate was evaporated and dissolved in 0.1% formic acid solution/methanol (v/v, 80:20). All of the samples were analyzed by LC-MS/MS on a Waters Acquity BEH C18 column with 0.1% formic acid in water/methanol as the mobile phase with gradient elution. The matrix effect, recovery, and repeatability, within laboratory reproducibility, and the LODs and LOQs of the two modified QuEChERS sample preparation methods were investigated and compared. Comparative results showed that the second method was obviously superior to the first method.