ITHACA, N.Y. -- Cornell University scientists report the accurate characterization of a sample representing 1 percent of the protein in a single red blood cell using electrospray mass spectrometry -- a feat that opens the door to a wide area of basic medical exploration.

The technique allows researchers to take samples as small as a single cell and identify many of its components with unusually high confidence, something that is almost impossible with current analytical technologies, the researchers say. The technique could be used for molecular investigations about human medical disorders at the cellular level.

"We have three orders of magnitude better sensitivity than what was possible before. The biggest thing about this is that you can get a complete identification of a totally unknown molecule. Just knowing the molecular weight at our accuracy level is a big help," said Fred W. McLafferty, Cornell professor emeritus of chemistry who led the work. Their accuracy provides less than 0.01 percent error. "With this, you can also measure masses of individual pieces of a molecule for further characterization."

The researchers -- McLafferty; Gary A. Valaskovic, a postdoctoral associate in McLafferty's lab; and Neil L. Kelleher, a doctoral student -- reported their studies in the journal Science (Aug. 29, 1996). Their work was funded by the National Institutes of Health.

Previous methods of analysis at this level, such as laser detectors, are useful only if the researcher knows what to look for. "But if you start without knowing anything about what's in a single cell, you need mass spectrometry," McLafferty said. "We don't even need to know that it's a protein."

Electrospray is a method for ionizing relatively big molecules and getting them into the gas phase. The solution containing the sample is sprayed at high voltage, forming charged droplets. These droplets evaporate, leaving the sample's ionized molecules in the gas phase. These ions c
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Contact: Larry Bernard
lb12@cornell.edu
607-255-3651
Cornell University News Service
30-Aug-1996