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On‐chip solid‐phase extraction pre‐concentration/focusing substrates coupled to atmospheric pressure matrix‐assisted laser desorption/ionization ion trap mass spectrometry for high sensitivity biomolecule analysis
Author(s) -
Navare Arti,
Nouzova Marcela,
Noriega Fernando G.,
HernándezMartínez Salvador,
Menzel Christoph,
Fernández Facundo M.
Publication year - 2009
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.3890
Subject(s) - chemistry , mass spectrometry , analytical chemistry (journal) , biomolecule , chromatography , ion trap , ionization , desorption , ion suppression in liquid chromatography–mass spectrometry , maldi imaging , detection limit , matrix (chemical analysis) , atmospheric pressure , sample preparation in mass spectrometry , electrospray ionization , matrix assisted laser desorption/ionization , tandem mass spectrometry , ion , adsorption , geology , biochemistry , oceanography , organic chemistry
Atmospheric pressure matrix‐assisted laser desorption/ionization (AP‐MALDI) has proven a convenient and rapid method for ion production in the mass spectrometric (MS) analysis of biomolecules. AP‐MALDI and electrospray ionization (ESI) sources are easily interchangeable in most mass spectrometers. However, AP‐MALDI suffers from less‐than‐optimal sensitivity due to ion losses during transport from the atmosphere into the vacuum of the mass spectrometer. Here, we study the signal‐to‐noise ratio (S/N) gains observed when an on‐chip dynamic pre‐concentration/focusing approach is coupled to AP‐MALDI for the MS analysis of neuropeptides and protein digests. It was found that, in comparison with conventional AP‐MALDI targets, focusing targets showed (1) a sensitivity enhancement of approximately two orders of magnitude with S/N gains of 200–900 for hydrophobic substrates, and 150–400 for weak cation‐exchange (WCX) substrates; (2) improved detection limits as low as 5 fmol/µL for standard peptides; (3) significantly reduced matrix background; and (4) higher inter‐day reproducibility. The improved sensitivity allowed successful tandem mass spectrometric (MS/MS) sequencing of dilute solutions of a derivatized tryptic digest of a protein standard, and enabled the first reported AP‐MALDI MS detection of neuropeptides from Aedes aegypti mosquito heads. Copyright © 2009 John Wiley & Sons, Ltd.