The Dry Electrolytic
Conductivity Detector is useful for low-level detection of chlorinated
and brominated solvents in environmental samples and other trace analyses.
In the picture above, a DELCD is mounted next to FID
and PID detectors on an SRI GC. The three chromatograms
shown below are from a similar SRI GC.
The DELCD is much
like the ECD in sensitivity, but it is much more
selective to halogens and blind to oxygen. The SRI DELCD differs from
the traditional wet ELCD in that it uses neither a solvent electrolyte
nor a nickel reaction tube, and the reaction products are detected in
the gaseous phase. In the high sensitivity mode (no hydrogen, using dry
cylinder air) the DELCD can detect down to the low picogram range. In
this mode, the DELCD is about 100 times more sensitive than the FID/DELCD.
However, the high sensitivity DELCD is susceptible to contamination from
high concentrations of chlorinated hydrocarbons and hydrocarbon solvents.