Atmospheric pressure ionization tandem mass spectrometric system for real-time detection of low-level pollutants in air

An atmospheric pressure ionization tandem mass spectrometric (API) (MS/MS) system is described that is capable of detecting, in real time, very low levels of contaminant ( 90/degrees/C), high humidity (>90% RH), and the presence of 3% CO/sub 2/ and >400 ppm NO/sub x/. This source is versatile enough to easily replace conventional electron impact or chemical ionization sources in existing mass spectrometers.