In the combo mode, the DELCO is operated after the FlO. The FlO signal is usually con–
nected to Channel 1 on the PeakSimple data system. The DELCO signal may be onChan–
nel 2 or 3. Each detector amplifier is labeled at the factory with the data channel to which it
has been connected. Detector signals may of course be connected to any available data
channel by simply attaching the white and black signal wires to the screw terminals on the
AiD
board inside the GC.
1) Set the FlOhydrogen and air flows for normal FlO operation. This is typically 25 ml/min
hydrogen ( corresponds to 25 psi ) and 250mVmin air ( typically 6 psi ). The exact pres–
sure required for each flow is labeled on the GC's right hand side.
2) Set the DELCO temperature setpoint to 260 using the front panel adjustments. This
number actually represents 1000°C. The DELCOwill heat up to about 254 and stabi–
lize. The quartz collector electrode
will
appear a bright red color due to the 1
aooc
tem–
perature.
,3)
In the FIDIDELCD combo mode, the FlO is normally operated on high gain or on hi–
filtered gain if the peaks aremore than 10 secondwide at the base. The hi-filtered gain
position is identical to the high gain except that extra noise filtering results in aquieter
baseline. The DELCO amplifier is normally operated on lowgain. In this configuration
the FlO and DELCOproduce approximately the same response to chlorinated peaks
such as TCE ( same peak area counts). The FlOwill generate approximately
4
area
counts per nanogram injected on columnwhile the DELCOwill generate 24 area counts
per nanogram of chlorinated hydrocarbon. ( see example chromatogrambelow).
I
- -
·
•
·
I
•
f--
•
.
I
.
,
FlO shows 500 area counts for 100 nanograms of Perchlorethylene
DELCO shows 250 area counts for 100 nanograms of
Perchlorethylene
.~
..
Man204.pub
