Purge-and-membrane with ECD. A new screening method for chlorinated aliphatic hydrocarbons

A new analytical technique; purge-and-membrane-electron capture detection (ECD), is described and applied to the screening of halogenated aliphatic hydrocarbons. A water sample is first purged by helium and the purged compounds are collected from the gas phase through a silicone membrane to the analytical system. Purge-and-membrane-ECD provides very fast, selective and sensitive screening method for halogenated aliphatic hydrocarbons. The method was compared with conventional direct membrane extraction. Results obtained show that the limits of detection (0.01–2 µg L−1) were comparable with both methods. However, significant shorter response times were measured with purge-and-trap than with direct membrane extraction.