Dual-micro-ESI source for precise mass determination on a quadrupole time-of-flight mass spectrometer for genomic and proteomic applications

摘要

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 pep-tides are better than 10 ppm.