Page 264 - Tandem Techniques
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The elements used for testing the equipment were tin (tetraethyl tin), iron (ferrocene), lead (tetraethyl
lead) and chromium (chromium trifluoroacetylacetonate) and the results obtained are shown in the four
chromatograms depicted in Figure 6.16.
It is seen that the tandem system clearly, and unambiguously, identifies the different organometalic
compounds as they are eluted. It is also seen that the system is generally very sensitive, the minimum
detectable amounts being about 10-100 pg. The lowest sensitivity was shown for the organchromium
compound. However, this lower sensitivity is partly due to chromium only representing a relatively
small proportion of the total organochromium complex. Some coal was spiked with selenium sulfide
and burned in the laboratory coal gasification apparatus and the coal oxidized in a wet oxygen stream.
Figure 6.16
Chromatograms Showing the Response of the GC/ICPAE Tandem
Instrument to Tin, Iron, Lead and Chromium from a Test Run
The coal bed was burned in two directions, one a forward burn where the burn proceeded in the
direction of the gas flow, and thus the gaseous products were swept away from the burning zone as
soon as they were formed. The second was a reverse burn, that allowed the oxidation
