VICI D-4-I-TQ-R - Manual (Page 19)

15
Troubleshooting
High Background Current
Low Sensitivity
Purple/
blue
Pink
Disconnect the column
and cap the column inlet
Baseline current is still high
(> 2.0 nA)
Leaks in the fittings of the
PDD plumbing
No detectable leaks.
Do a hydrogen leak test
(described on next page)
Check
discharge
color
Leaks inside the detector
cell itself Consult
Valco
Tighten leaking fittings
The detector isn’t leaking.
Check for column bleed
and/or leaks in the GC setup. Baseline current falls to
normal range (< 2.0 nA)
Possible bad carrier gas or
empty He bottle. Install a new
bottle.
Consult
Valco
Consult
Valco
Consult
Valco
Baseline current is still high
(> 2.0 nA)
Baseline current falls to
normal range (< 2.0 nA)
Baseline current is still high
(> 2.0 nA)
Baseline current falls to
normal range (< 2.0 nA)
Baseline current is still high
(> 2.0 nA)
Baseline current falls to
normal range (< 2.0 nA)
Sensitivity is in
acceptable range
Sensitivity is still
too low
Sensitivity is in
acceptable range
Sensitivity is still
too low
Sensitivity is in
acceptable range
Sensitivity is still
too low
Sensitivity is in
acceptable range
Remove column and
condition it, then run
a sample
Background current
remains high
Background current
drops to normal range Check column inlet for
leaks. Tighten fittings. Background current
increases
Check column position
according to drawing on
p. 11, and run a sample.
Background current
remains in normal range
Remove column and
bake detector at
300°C for four hours.
Install column and run
a sample.
Run
a sample
Refer to “Troubleshooting:
High Background Current” Reinstall column and check
background current
Normal background current
(
£ 2 nA)
High background current
(
> 2 nA)
Consult
Valco
Sensitivity is still
too low
Check background current
with column removed and
column inlet plugged
No Peaks
If the background current is stable but there are no peaks:
1. Check column flow.
2. Check the column insertion position (14.5 cm for capillary columns,
13.0 cm for packed columns).
3. If there are still no peaks, check to make sure that the GC is actually making
an injection.
4. If there are still no peaks, consult Valco.