Analysis of Small Molecule Compounds by Matrix-assisted Laser Desorption Ionization Mass Spectrometry with Fe3O4 Nanoparticles as Matrix

Abstract

The effect of matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) in analysis of small-molecule compounds, including amino acid, oligosaccharide and triglyceride, was investigated using a nano-triiron tetraoxide (Fe 3 O 4 ) matrix. After comparing with other nanoparticle matrices and organic-inorganic binary matrices, Fe 3 O 4 nanoparticles were selected as the matrix in MALDI-MS analysis of D , L -pyroglutamic acid, D , L -aspartic acid, L -proline, L -phenylalanine, sucrose, raffinose, tripalmitin and triolein. The effects of MALDI-MS experimental conditions on MS peak noise and signal intensity were investigated. The results showed that Fe 3 O 4 increased the MS peak strength and reduced the background noise. Nano-matrix was used to cover the sample, and the MS acquisition parameters were set to positive polarity and 70% laser power. The results showed that nano-Fe 3 O 4 was an ideal matrix for the detection of amino acids, oligosaccharides and triglycerides, and had better reproducibility and sensitivity than other matrices. The MALDI-MS analyses of D , L -pyroglutamic acid, sucrose, and triolein were performed using the nano-Fe 3 O 4 matrix. The relative standard deviations (RSDs) in in-spot and spot-to-spot repeatability were less than 3.2% and 6.0%, respectively. The linear correlation coefficients ( R 2 ) between MS peak intensity and concentrations were no less than 0.997 in the concentration range of 0.05–1.0 mg/mL. The results showed the potential quantitative power of the MALDI-MS analysis. Using Fe 3 O 4 nanoparticles as matrix, the amino acids, oligosaccharides and triglycerides were detected by MALDI-MS with better signal-to-noise ratio, reproducibility and sensitivity.