Basic HTML Version
DELCD - SRI Instruments
DELCD - Dry Electrolytic Conductivity Detector
48
|
|
|
|
●
Non-radioactive alternative to ECD
●
High sensitivity
detects down to 1 ppb
●
Selective to chlorinated and brominated molecules
●
Best used with headspace or purge & trap injectors
●
Can be combined with FID, NPD or TID detectors
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
and
detectors on an SRI GC. The three chromatograms shown below are from a similar SRI GC.
The DELCD is much like the
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.
A 50 ppb Japanese VOC standard was
placed into a VOA vial with water, and
allowed to equlibrate at room
temperature for 45 minutes before 1mL
of headspace was injected into the
on the SRI GC. The
chromatogram (center) shows all the
components and the solvent. The
DELCD (top) does not respond to the
solvent, and the
(bottom) does not
detect the 1,1,1-TCA.