Review of interactive carrier gases including ammonia in gas liquid chromatography

The use of interactive carrier gases can create new possibilities for gas c hromatography. In this review the possibility of utilising the ammonia and other active compounds is discussed. The influence of ammonia as carrier ga s on separation and detection performance in capillary gas chromatography i s discussed. Ammonia as the mobile phase resulted in improved peak symmetry , reduced retention factors and improved detection limits for aliphatic ami nes compared to nitrogen. Drastic selectivity changes towards some chloroph enol pairs were observed when ammonia was used as the mobile phase instead of nitrogen or helium. The selectivity of the chiral stationary phase XE-60 -L-Val-(S)-a-PEA (polysiloxane-L-valine-(S)-a-phenylethylamide) was drastic ally changed after it was exposed to ammonia for one week. The effect of am monia on the chromatographic performance was more pronounced at lower colum n temperature. The presence of 50% ammonia in the carrier gas was usually e nough for maximum effect on the peak symmetry and a good effect on the colu mn selectivity. Ammonia either as a carrier gas or as a mixture in the make -up gas improved the responses of the FID, NPD and ECD. (C) 1999 John Wiley & Sons, Inc.