Application of Modified Mesoporous Silica Materials for Analysis of Small Molecules by MALDI-TOF-MS / 分析化学

ABSTRACT

Mesoporous silica SBA-15 with a small organic molecular (1,8-Naphthalimide) was synthesized and used as matrix for MALDI-TOF-MS ( Matrix-assisted laser desorption/ionization time of flight mass spectrometry) analysis. A modified SBA-15 matrix, SBA-15-NA (1,8-Naphthalimide) was synthesized by covalently attaching SBA-15 to an 1 , 8-naphthalimide formed by 1 , 8-naphthalic anhydride and 3-( trimethoxysilyl) propylamine. The mass spectra obtained with SBA-15-NA exhibited less background interference ions, higher desorption/ionization efficiency, and higher peak intensity. The matrix was initially prepared in methanol and mixed with analyte at a 1∶1 volume ratio in vial. The solution of mixture was at a 10∶1 concentration ratio of matrix/analyte on a stainless steel target and allowed to air dry. The method was used to analyze various types of low molecular weight ( less than 500 ) chemical compounds such as monosaccharides, amino acids, phytohormones, drugs. Under the optimal conditions, it gave low detection limit of 1×10-9 g/L (Leucine, S/N=5) and good reproducibility (≤30%). The modified mesoporous silica materials have been employed in the urinary study for direct detection of metabolites.