THE MICRO-TRAP - AN ALTERNATIVE TO CRYOFOCUSING IN CAPILLARY GAS-CHROMATOGRAPHY

For routine analyses involving numerous samples or for field operation of on-site instruments, cryogenic traps are inconvenient: their operation is timeconsuming and automation is technically demanding. complete trapping and efficient band-focussing may be achieved at ambient temperature with micro-traps packed with suitable sorbents. Two approaches have been evaluated: if the boiling points of the analytes are within a range of about 100°C, a single-sorbent trap and direct coupling to the column are recommended; for samples containing components wih widely different volatilities, a trap composed of two or more segments with complementary affinties and coupling to the chromatographic column under carrier-gas flow-reversion is preferable. The procedure has been evaluated for airborne C1 and C2-halocarbons; it is also applicable to trace analysis of other volatile organic air pollutants. © 1990 Friedr. Vieweg & Sohn Verlagsgesellschaft mbH.