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Updated: Aug 31, 2026

Analyzing Large Protein Complexes by Structural Mass Spectrometry
Published on: June 20, 2010
Dual-micro-ESI source for precise mass determination on a quadrupole time-of-flight mass spectrometer for genomic and
Jason W Flora1, Allison P Null, David C Muddiman
1Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, VA 23284, USA.
Abstract:
A universal dual-electrospray (ESI) source is demonstrated on a quadrupole orthogonal-accelerated time-of-flight mass spectrometer (Q-ToF-MS) for both genomic and proteomic applications. This facile source modification enables internal calibration for consistent mass measurements by a mainstream MS platform and requires no mixing of analyte and calibrant prior to ion formation. In this report, the dual-sprayer is demonstrated in the negative-ion mode for internal calibration of polymerase chain reaction (PCR) amplicons generated from synthetic and genomic templates as well as a proteolytic digest of a naturally phosphorylated protein. For all PCR amplicons, experimentally determined average mass measurements are well within the instrument specifications of better than 0.01%. For the proteolytic fragments of the phosphoprotein, average mass errors of the isotopically resolved peptides are better than 10 ppm.
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