Fast gas chromatog. sepns. can be achieved by vacuum-outlet operation and by applying narrow-bore columns. The combination of 50 mm internal diam. columns with ion trap mass spectrometric detection is evaluated. Detection limits in the electron ionization mode, and in the chem. ionization mode using CH4 as the reaction gas, are 1 pg and 5 pg, resp. Owing to the high sensitivity of the ion trap mass spectrometer, a significant improvement in the working range in comparison with other detection systems is obtained. The small column flows cause no loss of mass spectral resoln. and sensitivity. The performance of the system is demonstrated by the anal. of some real-world sample