QuEChERS sample pre-processing with UPLC–MS/MS: A method for detecting 19 quinolone-based veterinary drugs in goat’s milk

Abstract We develop and validate a method for the rapid determination and identification of 19 quinolones in goat’s milk by combining the QuEChERS technique with ultra-performance liquid chromatography–tandem mass spectrometry. Plackett–Burman and Central Composite Design methods were used to select the parameters that best promote the extraction efficiency, which led to extraction with acetonitrile/5% formic acid, followed by phase separation with sodium citrate, disodium hydrogen citrate, Na2SO4, and NaCl as optimal. The supernatant was then extracted and cleaned by dispersive solid-phase extraction using C18 and Na2SO4 aided by low-temperature clean-up. The method was validated, with limits of quantification (LOQs) of 5 ppb, specificities of 1/5 LOQ, linearities (R2) > 0.9853, recoveries of 73.4–114.2%, repeatabilities