Multiplexed MS/MS on a Quadrupole Ion Trap Mass Spectrometer
Richard W. Vachet, Ph.D. and Jonathan Wilson Ph.D.
The Quadrupole Ion Mass Spectrometer (QITMS) is used extensively in proteomics research. It provides primary sequence information for proteins and peptides and can be used to rapidly and sensitively identify proteins in complex mixtures when coupled with high-performance liquid chromatography (HPLC). For very complex mixtures like those increasingly found in proteomic and quantitative proteomics analyses, a major limitation of the QITMS is its difficulty with rapidly analyzing multiple compounds simultaneously. The novel aspect of this invention is a new encoding scheme that will allow the existing QITMS to be extended to permit multiple compounds to be analyzed concurrently, which will dramatically improve sample throughput and facilitate proteomics research. The encoding scheme allows the parent/product ion relationships to be easily determined after isolation and dissociation of multiple ions, providing a link between parent ions and their product ions by encoding parent ion abundances in a known way from the first product ion spectrum to the second.
- Improvement of mass spectrometry method
- Identification of proteins revealing the molecular basis of diseases and other biological processes, thus can speed development of new drugs
This invention has several key advantages over existing means of performing tandem mass spectrometry (MS/MS).
- It enables the sequence analysis of n peptide ions in as little as 2 mass spectra
- It can extend existing QITMS systems with minor hardware and software modifications, thus further enhancing the sequencing and protein identification capabilities of QITMS.
- If combined with HPLC, it rapidly performs structural analyses of multiple compounds that simultaneously elute during a chromatographic run, thus allowing structural analysis of a more complete set of compounds from complex mixtures.
- It may improve the identification of proteins in low abundances
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