In a lab in Bull Run Hall, George Mason University's most sophisticated mass spectrometer system is being used to conduct cutting edge research in protein identification. The Thermo Finnegan mass spectrometer is operated under the care of Dr. Weidong Zhou.

The system is really a combination of two instruments: a high performance liquid chromatography (HPLC) system connected to the linear ion trap mass spectrometer. The interface is a nanspray source operating at atmospheric pressure with electrospray ionization.

CAPMM uses a Thermo Finnegan LTQ linear ion trap
mass spectrometer for protein identification.

The HPLC system pumps a steady stream of solvents at a flow rate of around 100 nanoliters per minute. A sample such as the tryptic digest of human serum is injected into the flow. With the help of a capillary containing a sorptive material, the sample mixture is then separated into individual components. As each component elutes from the HPLC system, it is ionized by a 3-5 kilovolt charge and sprayed towards an aperature in the mass spectrometer sources. The charged ions are then recorded, fragmented and recorded again until enough spectral data is obtained to positively identify the proteins. This method will allow the research scientists at CAPMM to sift through the proteins present in sera to find the biomarkers needed to aid in the diagnosis and treatment of cancers.

For more detailed information about the Thermo Finnegan LTQ system as well as some incredible multimedia graphics demonstrating the instrument's principals of operations,, see the Thermo web site.