Novel polymer composite to eliminate background matrix ions in matrix assisted laser desorption/ionization-mass spectrometry

Lin Hua, Low Teck Yew, Wei Meng, Mary B. Chan-Park, Siu Kwan Sze

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) is rarely used for the analysis of small molecules (<700 Da) because the low m/z signal is overwhelmed by a high background of matrix ions. We have developed a solution to this problem that employs a novel polymer composite which is formed by covalently cross-linking α-cyano-4-hydroxycinnamic acid (HCCA) to SU-8 photoresist via cationic photo-polymerization. Since the HCCA molecules are immobilized, background noise resulting from the matrix ions is significantly reduced or eliminated. Moreover, owing to the hydrophobic surface of the polymer film, the sample spots shrink during solvent evaporation and thus the analytes can be concentrated. As a result, this polymer composite improves detection sensitivity and extends the analyzable species to the low-mass region. The covalent incorporation of HCCA with SU-8 was validated with reflectance FT-IR spectroscopy, and the polymer surface was characterized with scanning electron microscopy (SEM). Using MRFA, a small peptide as a standard, 8 mg of HCCA per mL of SU-8 photoresist was found to yield the highest sensitivity and the lowest background noise. Analytes such as peptides or small organic molecules were further examined on this composite surface and no analyte degradation was observed. In a trial of peptide mass fingerprinting of cytochrome c on the composite substrate, the inclusion of low m/z tryptic peptides in the database search dramatically improved the protein identification probability score.

Original languageEnglish
Pages (from-to)1223-1230
Number of pages8
JournalAnalyst
Volume132
Issue number12
DOIs
Publication statusPublished - 27 Nov 2007
Externally publishedYes

Fingerprint

Matrix-Assisted Laser Desorption-Ionization Mass Spectrometry
peptide
Peptides
Ionization
Mass spectrometry
Desorption
desorption
Polymers
ionization
polymer
mass spectrometry
laser
Ions
matrix
Acids
ion
Lasers
acid
Composite materials
Photoresists

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy
  • Electrochemistry

Cite this

Novel polymer composite to eliminate background matrix ions in matrix assisted laser desorption/ionization-mass spectrometry. / Hua, Lin; Teck Yew, Low; Meng, Wei; Chan-Park, Mary B.; Sze, Siu Kwan.

In: Analyst, Vol. 132, No. 12, 27.11.2007, p. 1223-1230.

Research output: Contribution to journalArticle

Hua, Lin ; Teck Yew, Low ; Meng, Wei ; Chan-Park, Mary B. ; Sze, Siu Kwan. / Novel polymer composite to eliminate background matrix ions in matrix assisted laser desorption/ionization-mass spectrometry. In: Analyst. 2007 ; Vol. 132, No. 12. pp. 1223-1230.
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