A nano LC-MALDI mass spectrometry droplet interface for the analysis of complex protein samples

PLoS One. 2013 May 9;8(5):e63087. doi: 10.1371/journal.pone.0063087. Print 2013.

Abstract

The integration of matrix-assisted laser desorption ionization (MALDI) mass spectrometry with an upstream analytical separations (such as liquid chromatography and electrophoresis) has opened up new opportunities for the automated investigation of complex protein and peptide mixtures. The ability to efficiently analyze complex proteomic mixtures in this manner is primarily determined by the ability to preserve spatial discrimination of sample components as they leave the separation column. Current interfacing methods are problematic in this respect since minimum fraction volumes are limited to several microliters. Herein we show for the first time an LC-MALDI interface based on the formation, processing and destruction of a segmented flow. The interface consists of a droplet-generator to fractionate LC effluent into nL-volume droplets and a deposition probe that transfers the sample (and MALDI matrix) onto a conventional MALDI-MS target. The efficacy of the method is demonstrated through the analysis of Trypsin digests of both BSA and Cytochrome C, with a 50% enhancement in analytical performance when compared to conventional interface technology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle
  • Chromatography, Liquid / methods*
  • Cytochromes c / analysis
  • Cytochromes c / chemistry
  • Fluorescein-5-isothiocyanate / chemistry
  • Fluorescent Dyes / chemistry
  • Nanotechnology / methods*
  • Proteins / analysis*
  • Proteins / chemistry
  • Reproducibility of Results
  • Serum Albumin, Bovine / analysis
  • Serum Albumin, Bovine / chemistry
  • Serum Albumin, Bovine / metabolism
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods*
  • Trypsin / metabolism

Substances

  • Fluorescent Dyes
  • Proteins
  • Serum Albumin, Bovine
  • Cytochromes c
  • Trypsin
  • Fluorescein-5-isothiocyanate

Grants and funding

XN acknowledges an Annual Adventure in Research Grant from the University of Southampton. AdM and FP gratefully acknowledge financial support from the Swiss Federal Institute of Technology, ETH Zürich. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.