Gas chromatography in water analysis—I organic profiles of water sources

A method has been developed and used extensively for the routine chromatographic scanning of water sources for trace organic compounds. The method involves solvent extraction of the water with dichloromethane, followed by analysis of the concentrated extract by gas chromatography on a glass SCOT capillary column with flame ionisation detection to yield a water profile. Over 600 extracts from rivers, canals, reservoirs and various stages of water treatment, collected between January 1979 and October 1980 as part of a potability study, were examined. The profiles were quantified using n-paraffin standards and a computerised data system. Components were detected at levels as low as 0.01 μg 1^?1 in the water samples.

A Kratos MS-30 double-beam mass spectrometer equipped with a DS-50 data system was used in conjunction with gas chromatography to identify chemical types in over 60 of the organic extracts. Components were generally identified at levels as low as 0.1 μg 1^?1 in the water samples. Many components did not give molecular ions and reference spectra were generally unavailable. In such cases, accurate mass measurement using the double-beam technique, which allowed the calculation of atomic compositions for fragment and molecular ions, was particularly valuable.