Miniaturized EI/Q/oa TOF mass spectrometer

A miniaturized orthogonal time-of-flight mass spectrometer with an electron impact ionization ion source and a rf quadrupole ion guide has been developed. A mass resolving power of m/Deltam = 5500 has been obtained in a 0.4 m instrument. The addition of helium at pressures of about 4.0 mtorr into the ion source showed collisional focusing taking place in the rf quadrupole, An automated gas chromatograph designed for air monitoring applications has been coupled to the time-of-flight mass analyzer and tested for the detection of simulants of chemical-warfare agents. (C) 2001 American Society for Mass Spectrometry.