Ionic liquid matrix-based dispersive liquid–liquid microextraction for enhanced MALDI–MS analysis of phospholipids in soybean

• ILM-based DLLME for enhanced MALDI-MS analysis of phospholipids in soybean.
• 8–125 fold improvement in the signal intensity and limit of detection for phospholipids.
• The reason for improvement is effective extraction and ionization of phospholipids.

Ionic liquid matrix (ILM) is found to be a very versatile substance for analysis of broad range of organic molecules in matrix-assisted laser desorption/ionization mass spectrometry (MALDI–MS) due to good solubility for a variety of analytes, formation of homogenous crystals and high vacuum stability of the matrix. In the present work, an ILM, cyno-4-hydroxycinnamic acid-butylamine (CHCAB) was employed in dispersive liquid–liquid microextraction (DLLME) as sample probe and matrix for extraction and ionization of phospholipids from food samples (soybean) prior to MALDI–MS analysis. With the employed technique, 8–125 fold improvement in signal intensity and limit of detection were achieved for the analysis of phospholipids. The best extraction efficiency of phospholipids in ILM–DLLME was obtained with 5 min extraction time in presence 30 mg/mL CHCAB and 1.2% NaCl using chloroform as an extracting solvent and methanol as a dispersing solvent. Further, the developed ILM–DLLME procedure has been successfully applied for the analysis of phospholipids in soybean samples in MALDI–MS.