Determination of Purgeable Halocarbons and Aromatics by Photoionization and Hall Electrolytic Conductivity Detectors Connected in Series

Abstract

The applicability of the purge-and-trap technique, combined with a photo ionization detector (PID) and a Hall electrolytic conductivity detector (EICD) connected in series to the determination of 46 volatile organic compounds, is investigated. Both packed and open tubular capillary columns are evaluated. Twenty compounds arranged in nine groups coelute on the 1% SP-1000 on Carbopack B column, and 15 compounds arranged in five groups coelute on the n-octane/Porosil column. Preliminary experiments with wide-bore capillary columns indicate that either the VOCOL or the DB-624 open tubular capillary column can be used for the primary analysis of Methods 8010 and 8020 compounds. However, neither column is able to completely resolve all compounds. Twenty compounds arranged in eight groups coelute on the VOCOL (diphenyl dimethyl polysiloxane with crosslinking moieties, Supelco, Inc.) open tubular capillary column and 11 compounds arranged in five groups coelute on the DB-624 (cyanopropyl phenyl dimethyl polysiloxane, J&W Scientific) open tubular capillary column. Method precision of the purge-and-trap technique with a PID and a Hall EICD connected in series, as assessed from the instrument response at a known concentration per compound, is better than ± 30% (except for dichloromethane) and has a mean value of ± 12%. Method accuracy ranges from 82 to 104% for groundwater samples. Method detection limits vary with each compound and range from 0.1 to 0.9 ppb for water samples and 1 to 5 ppm for soil samples.