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Analytes Using Mass Spectrometry (CRIMS)

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Steven M. Colby,1 Jiuwei Teng,2 Yohannes Teffera,2 John J. Manura,1 and Fred Abramson2, 1Scientific Instrument Services, 1027 Old York Road, Ringoes NJ 08551. 2Dept. of Pharmacology, The George Washington University, 2300 Eye Street, NW, Washington, DC 20037.

The Chemical Reaction Interface Mass Spectrometer (CRIMS) is intended to facilitate the use of nonradioisotopic labeling1,2. Not only are radioisotopes expensive and difficult to use, but they cannot be employed in some applications, such as the analysis of drug metabolism in children. CRIMS involves the atomization of sample in a microwave-induced plasma followed by recombination with a reactant gas. Isotopic abundance of the analyte can be measured by monitoring the masses of simple products. For example, the masses of CO2, NO, and HCl provide reliable indications of the carbon-13, nitrogen-15, and chlorine content in the original molecule.

We report the development of a new CRIMS interface capable of accepting either gas chromatographic effluent or the desolvated output of a liquid chromatograph. The microwave cavity is designed to be inexpensive and compatible with a variety of commercially available mass spectrometers. The new cavity incorporates improved design and surface conduction that results in a more stable discharge. We will characterize the results of all design improvements and report experimental examples intended to demonstrate the versatility of the new interface. The compatibility of the interface with several liquid chromatographic desolvation techniques will also be explored.

References:

  1. Abramson, F.; CRIMS: Chemical Reaction Interface Mass Spectrometry, Mass Spectrom. Rev. 1994, 13, 341-356.
  2. Song, H., and Abramson, F. P.; Nitrogen trifluoride: A new reactant gas in CRIMS (Chemical Reaction Interface Mass Spectrometry) for detection of phosphorus, deuterium, chlorine, and sulfur. J. Am. Soc. Mass Spectrom. 1995, 6, 421-427.