Evaluation of various clean-up sorbents in kale followed by LC-MS/MS analysis of pesticides.

Unlabelled: Chlorophyll-rich samples, such as kale, interfere with the analysis of residual pesticides and adversely affect the integrity of tandem mass spectrometers. Dispersed solid-phase (d-SPE) extraction using graphitized carbon black effectively removes pigments from kale extracts; however, it also reduces the recoveries of 30 pesticides. To overcome this, alternative sorbents, including ENVI-Carb, ChloroFiltr, and Z-Sep+, were evaluated in this study. A sorbent combination based on 50 mg of Z-Sep+ was most advantageous (21/30), good precision (< 15%), excellent pigment removal capacity, and low matrix effect. The limit of quantification (0.0001-0.0040 mg/kg) was lower than the Korean maximum residue limits levels. The proposed method was validated according to international guidelines and applied to real kale samples. The results demonstrated that d-SPE using Z-Sep+ provides an effective strategy for ensuring mass spectrometry system integrity and improving the analytical accuracy in chlorophyll-rich samples.

Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01101-3.