Tuning Of The Ecd Channel - Scion Instruments 456-GC Reference Manual

Scion Instruments

TUNING OF THE ECD CHANNEL

Set the temperature of the column oven at 50ºC.
•
Turn off the make-up gas to the ECD.
•
• Switch V2 to the inject position and set the rear EFC-24 to give a flow of 20
ml/min, measured at the outlet of the ECD.
Switch V2 back to the fill+backflush position and set the aux rear EFC-24 to
•
give a flow of 20 ml/min, again measured at the outlet of the ECD.
• Measure the flow at vent 2 and adjust the needle valve to give a flow of 20
ml/min.
Set the rear DEFC-13 to 10 ml/min Ar/CH
•
Program the system as described in the Operation section of this manual.
•
Tuning the backflush
Determine the backflush time with a sample containing low ppm N
Initially run the sample with a backflush time of 5.0 minutes.
Reduce this backflush time until the N
the backflush to allow full recovery of the N
The signal disturbance due to the valve switching should not influence the
N O peak.
2
A representative chromatogram for an injection of lab air containing ± 320
ppb N O is given in figure 1.
2
Figure 1: Example chromatogram for the ECD channel of the Greenhouse Analyzer
Scion Instruments
N O
2
Greenhouse Gases Analyzer Reference Manual
.
4
O recovery starts decreasing. Set
2
O.
2
O.
2
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