THE TINY-TOF MASS-SPECTROMETER FOR CHEMICAL AND BIOLOGICAL SENSING

Mass spectrometry is the most sensitive and specific detection methodo logy ever developed for a broad range of chemical substances. It is wi dely used in environmental, medical, military, and industrial applicat ions, and would see even broader use if the equipment could be made po rtable enough for field measurements. To date, however, the equipment used for high-performance mass spectrometry has been large, heavy, and power-hungry, precluding its use in remote field measurements, The Ap plied Physics Laboratory has developed a small, powerful, time-of-flig ht mass spectrometer in a collaborative program with the Johns Hopkins Medical Institutions and the University of Maryland. Miniaturization of the equipment required the development of new techniques for ion fo rmation in the ion source region and the use of kinetic-energy spread correction schemes based on ion reflectrons. Sampling and ionization s chemes for solids, liquids, and vapors have led to promising conceptua l designs for microorganism identification, environmental monitoring, and law enforcement analytical tools.