The article on "Longitutional Cryogenic Modulation in GC . . . ." in LC GC Europe, 13 (#6), 428 (2000), cought my attention, because some time ago we needed a considerable effort to satisfactorily cool a short section of column with liquid CO2 (Journal of Chromatography, Biomedical Applications, 228, 75 (1982)). Later we solved the problem by removing the metal sheath (guide for the CO2, or "cool trap") on the column and allowed the cold CO2 gas to blow out of a fine capillary directly onto the column. It worked, also reheating very quickly after stopping the flow of CO2. Unfortunately, timewise, there was no chance to bring the underlying project to majurity for puplication. Therefore my question: Has anybody been successful in effecting "cryogenic modulation " by focusing the cooling gas on the capillary column without a bulky guide (trap)?