HIGH-SPEED GC AIR MONITOR USING CRYOINTEGRATION FOR SAMPLE COLLECTION

A high-speed gas chromatograph for the direct analysis of atmospheric pressure vapor samples is described. The instrument uses a gas cooled and electrically heated capillary metal trap tube for cryofocusing and preconcentrating (cryointegration) air samples. After sample collection, gas flow direction through the trap tube is reversed, and the tube is heated by a capacitive discharge power supply. The 10 ms wide sample plug is introduced into an 8 m long capillary column equipped with a midpoint make-up gas supply. Relatively simple mixtures are separated in about 30 s. The effects of sample collection time on calibration plot linearity and detection limits are presented. The use of a make-up gas to prevent ice formation in the trap tube during sample collection is described. © 1994 Oxford University Press.