-1
I
_o—
I
|
|
|
S02 BY GAS CHROMATOGRAPHY
TOTAL SULFUR
0
1
1
1200
1
1
1600
1
2000
1
1
2400
1
1
0400
direct readout
printous
12/30/68
12/29/68 TIME, hour·
Comparison of responses of gas chromatographic system and the flame photometric detector to ambient air containing S02
Figure 8.
ment of
a commercial version of this chromatograph would be an important
contribution to agencies concerned with limiting the emissions of this gas. Gas Chromatographic Approach for
Measuring Atmospheric Carbon Monoxide and Methane
commercially available nondispersive infrared carbon monoxide (CO) analyzers can measure concentrations of 1 or 2 ppm, their responses are generally nonlinear and are affected by carbon dioxide, water vapor, and hydrocarbons. For this reason NAPCA is interested in developing a more sensitive and reliable CO monitor. One method of achieving this desired sensitivity and specificity is by applying gas chromatographic techniques. Gas chromatography has been used for years to measure low concentrations of gaseous materials; however, it has not been accepted as a routine monitor for certain air pollutants. Development has been slow because materials to polluted air tend to intercommon fere with most gas chromatographic measurements. Recently, several investigators (6, 7) have coupled gas chromatographic techniques with the catalytic conversion of carbon monoxide to methane to measure ppm levels of CO in air samples. These investigators, however, did not mention the quantitative aspects of the CO to CH4 conversion and restricted their techniques to manual introduction of samNAPCA scientists (
