Flame ionization detectors, lead analysis

Dual Detectors. Most dual detectors are run in parallel, the column effluent being split and run through both of them simultaneously. In GC the technique is known as dual channel GC usually, one of the detectors chosen is universal and the other is highly selective. Figure 6.6 shows the analysis of a commerical gasoline sample with dual detection by flame ionization (FID) and electron capture (ECD). The FID detects all the hydrocarbons, but the ECD is selective for the alkyl lead additives in gasoline and permits their detection without interference from the hydrocarbons. 

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