Analysis of Nitropolycyclic Aromatic Hydrocarbons in Fine Particulate Matter by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Using Fe3O4/ZIF-8 Magnetic Nanocomposites as Matrix

Core-shell magnetic metal organic nanocrystals were synthesized and used as matrix for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Four nitropolycyclic aromatic hydrocarbons (nitro-PAHs) were successfully detected by using negative-ion MALDI-TOF MS without background interference. Furthermore, the magnetic nanocomposites (MNCs) coated with zeolitic imidazolate framework-8 (ZIF-8) showed excellent adsorption and enrichment capacity, and can be isolated with a magnet and directly spotted on the stainless steel plate for MALDI measurement. It was also analyzed nitro-PAHs in PM2.5 samples using the ZIF-8-coated magnetic nanocomposite as adsorbent and matrix.