MEASUREMENT OF GASES BY A SUPPRESSED CONDUCTOMETRIC CAPILLARY ELECTROPHORESIS SEPARATION SYSTEM

This paper describes the direct measurement of soluble ionogenic atmos pheric gases by a suppressed conductometric capillary electrophoresis separation system (SuCCESS). A small circular wire loop is incorporate d at the sampling end of a fused silica capillary located immediately at the tip in the same plane as the capillary. When the loop is dipped into a solution and withdrawn, a liquid film is formed on it, The fil m is in fluid communication with the capillary and acts as a microrese rvoir. When the film end is lifted relative to the destination side, a ll or part of the film contents can be injected into the capillary. To perform gas sampling, a series of automated operations are conducted with a commercial CE instrument modified in a minor fashion: the film- bearing loop is lowered into a sample chamber, and air is sampled for a preset period of time at a preselected flow rate (typically 1 min at 100 cm(3)/min), The capillary is then lifted to introduce an aliquot from the film for analysis and then dipped into the running electrolyt e source vial, and electrophoresis is commenced. Under the above sampl ing conditions, 1 ppb SO2 can be detected. The system should be applic able for use with other detection modes and nonaqueous electrolytes.