MicroSPE-nanoLC-ESI-MS/MS using 10-microm-i.d. silica-based monolithic columns for proteomics

Area of Science:

• Analytical Chemistry
• Biochemistry
• Mass Spectrometry

Background:

• Micro-Solid Phase Extraction (microSPE) coupled with nano-Liquid Chromatography (nanoLC) and Electrospray Ionization Mass Spectrometry (ESI-MS) is crucial for analyzing complex biological samples.
• Traditional methods often suffer from dead volume, clogging, and reproducibility issues, limiting sensitivity and throughput.

Purpose of the Study:

• To develop and evaluate novel silica-based monolithic capillary columns with integrated nanoESI emitters for enhanced microSPE-nanoLC-ESI-MS analyses.
• To assess the performance, robustness, and reproducibility of the integrated column system.

Main Methods:

• Fabrication of silica-based monolithic capillary columns (25 cm x 10 microm i.d.) with integrated nanoESI emitters.
• Coupling of microSPE and nanoLC separation directly to a linear ion trap mass spectrometer.
• Analysis of a tryptic digest of Shewanella oneidensis proteins (300 ng sample).

Main Results:

• The integrated nanoESI emitter eliminated dead volume, enabling stable electrospray at ~10 nL/min flow rates.
• A single 4-h LC-MS/MS analysis identified 5510 unique peptides, covering 1443 distinct proteins.
• The monolithic ESI emitter demonstrated enhanced resistance to clogging and good run-to-run reproducibility.

Conclusions:

• Silica-based monolithic capillary columns with integrated nanoESI emitters offer a high-quality and robust solution for microSPE-nanoLC-ESI-MS.
• This integrated system significantly improves protein identification efficiency and reproducibility in complex proteomic analyses.
• The technology holds promise for advancing sensitive and reliable biological sample analysis.