Optimal Conditions of Purge Trap/On-Column Cryofocusing Method with Capillary Gas Chromatography for Determination of Volatile Halogenated Hydrocarbons in Aqueous Samples

Abstract

The dynamic purge trap and simple on-column cryofocusing method with capillary gas chromatography was used to study the basic optimal conditions for determination of the trace levels of volatile halogenated hydrocarbons (VHHs) in an aqueous sample. The pre-concentration method consists of the following 4 main analytical steps ; 1. purging the aqueous sample, 2. trapping at adsorbent, 3. thermal desorption, and 4. retrapping on a trap column (cryofocusing). Using the optimal conditions of the step allowed us sufficient quantitative transfer of VHHs to a capillary column with narrow band width and such good chromatographic resolution with high reproducibility that we were able to successfully apply it to rainwater containing sub ppb levels of mixed VHHs which had very similar boiling points.