Page 7 - Shimadzu GC-8A

Electron Capture Detector (GC-8AIE)

Linear ECD with high sensitivity and wide dynamic range
Electrode
The constant-current ECD maintains a constant current flow in
the detector. It offers excellent performance of a linear dynamic 63 Ni source
range of 10,000 and 0.2 pg (Υ-BHC) minimum limit of detection,
and greatly restricts peak abnormalities such as negative peaks. Purge gas
Exhaust
Column
Switchable detector current
Carrier gas
The standing current flowing in the detector can be switched in Fig. 10 ECD Cell
three stages for convenient analysis of samples across a wide
concentration range.

Comprehensive contamination countermeasures Chloroform 7.5ppb
Tetrachloromethane
The system features a programmed heating system to prevent Dichlorobromomethane
6.4ppb
detector contamination (column oven heating starts only after
the detector reaches the set temperature) and a purge system
Trichloroethylene
to maintain carrier gas purging and keep the detector in 1,1,2-trichloroethane
1,1,1- Tetrachloroethylene
standby status even when the detector is not being used for trichloroethane 1,1,1,2-
Chlorodibromomethane tetrachloroethane
analysis. 2ppb Chloroform
1,1,2,2-
tetrachloroethane
Purge flow line reduces stabilization time
The purge flow line allows purging of the interior of the Fig. 11 Chromatogram of Trihalomethane
detector by carrier gas when the detector remains mounted in
the gas chromatograph but is not used.
This prevents oxidation by oxygen in the air and ensures stable
Electrode for FID monitor (option)
operation the next time the detector is used. Cooling fan
Photomultiplier
Quartz cylinder
Flame Photometric Detector (GC-8APFp)
Nozzle
Interference filter
Flame Quartz tube Quartz window
Air
The FPD cell is designed so that the flame will not be H2
Column
extinguished by a solvent overload.
FID monitor electrode Carrier gas
Fig. 12 FPD Cell
The FID monitor electrode in the detector permits extraction of
the FID signal.
*Requires the FID monitor kit (Special Accessory: P/N 221-23950-91)
Methyl parathion (20ng)
Forced cooling system
Ethyl parathion (20ng)
To ensure a low noise level and long service life, the
photomultiplier tube is kept cool by a blower when the
Thiophene
detector is maintained at a high temperature. (2ng)
EPN (20ng)
Complete safety FID monitor
FPD
The photomultiplier tube is protected against damage from
exposure to high light levels by a sensing circuit which cuts
Fig. 13 Analysis of Trace Thiophene Fig. 14 Analysis of Organophosphorus
power to the tube if anomalous conditions are detected. in Benzene (S mode) Pesticides (P-mode)

GC-8A Series
Gas Chromatograph 7