Technology Notes #1

Technology Notes - Q TOF Mass Spectrometry

By Robert B. Harris, Ph.D.
President and CEO

CBI has made an important addition to its mass spec inventory, a new Q TOF mass spectrometer. This instrument, which can operate either with or without a front-end HPLC in either electrospray or nanospray modes, expands CBI's proteomics capabilities, its small molecule analysis capabilities, and its sequence analysis capabilities by mass spec methods. The Q TOF has found immediate use in CBI's government contracts, and has facilitated proteomic comparisons of different select agent pathogens.

In just one example of its utility, the Q TOF is being used to analyze unqualified samples, provided by CBI's government sector customers, for the presence of particular bio agent toxins. Reverse-phase chromatography coupled with the time-of-flight mass spectrometer allows both the purification of these toxins and concurrent analyses for the correct mass.

The suspect samples and standards are injected onto a reverse phase column and then the column is developed under a particular set of elution conditions. The HPLC effluent enters the mass spectrometer, which dries the solvent away from the bio agent, and then the bio agent is analyzed on the basis of molecular weight.

Upon completion of the LC/ES/MS run, the Total Ion Count (TIC) (representative of all ions regardless of molecular weight in the sample over the duration of the HPLC run) is plotted as a function of elution volume (time). The abundance of the particular bio agent (of known mass) is extracted from the TIC plot (Extracted Selected Ion Monitor, or ESIM for short) and the mass ion peak area is integrated and assigned a value for the bio agent.

The higher the concentration of bio agent in the unqualified test sample, the proportionately larger the area of the extracted ion peak.

Commonwealth Biotechnologies, Inc. 601 Biotech Drive, Richmond, VA 23235 800-735-9224 (800-RELY-CBI) FAX: 804-648-2641 email: info@cbi-biotech.com