A novel magnetic multi-walled carbon nanotube-based magnetic solid-phase extraction combined with dispersive liquid–liquid microextraction method for the determination of four phenoxy carboxylic acid herbicides in food crops by using ultra-high performance liquid chromatography-tandem mass spectrometry

A method involving MSPE-DLLME coupled with UHPLC-MS/MS was developed for the determination of four phenoxy carboxylic acid herbicides in food crops.