Small-molecule analysis with silicon-nanoparticle-assisted laser desorption/ionization mass spectrometry

Area of Science:

• Analytical Chemistry
• Materials Science
• Spectrometry

Background:

• Conventional matrix-assisted laser desorption/ionization (MALDI) suffers from matrix background interference, particularly in the low mass range.
• Optimizing matrix properties is crucial for improving sensitivity and reducing noise in mass spectrometry.
• Developing new matrices can enhance the analysis of small molecules in complex biological and environmental samples.

Purpose of the Study:

• To investigate silicon nanopowder as a novel matrix for laser desorption/ionization mass spectrometry (LD-MS).
• To evaluate the performance of silicon nanopowder compared to conventional MALDI matrices.
• To establish an optimized protocol for silicon nanoparticle-assisted LD-MS and assess its applicability for analyzing various analytes.

Main Methods:

• Application of silicon nanopowder (5-50 nm) as a matrix in laser desorption/ionization mass spectrometry.
• Investigation of particle size and sample preparation effects on background spectra and analyte signals.
• Analysis of diverse analytes (drugs, peptides, pesticides, acids) using positive and negative ion modes.
• Surface characterization of the silicon nanopowder matrix.

Main Results:

• Significantly reduced matrix background interference in the low mass range compared to conventional MALDI.
• Achieved low femtomole per microliter detection limits for drugs like propafenone and verapamil.
• Demonstrated tolerance to salt contamination, enabling direct analysis of analytes in untreated urine and soil extracts.
• Observed high selectivity, potentially due to analyte-dependent precharging in solution.

Conclusions:

• Silicon nanopowder is a highly effective and selective matrix for LD-MS, offering significant advantages over traditional MALDI matrices.
• The method provides enhanced sensitivity, reduced background noise, and improved tolerance to sample contaminants.
• Silicon nanoparticle-assisted LD-MS presents a practical, potentially low-cost tool for the sensitive analysis of small molecules in complex matrices.