8
Troubleshooting
Investigating Peak Issues
112
ISQ User Guide
Thermo Scientific
Ghost Peaks
General
Incomplete elution of
previous sample
Increase the final oven program
temperature or total run time.
Increase the column flow rate.
Carrier gas is contaminated Replace the gas cylinder or filter.
Laboratory glassware has
caused contamination
Ensure the glassware is clean and
contaminant-free.
Injected sample has
decomposed
Decrease the injection port temperature.
Use the on-column injection technique.
Injection solution has
matrix present
Adequately clean up your sample prior
to injection.
Inlet or pneumatics are
contaminated
Remove the column and bake out the
inlet.
Use a high-quality septum.
Replace the split vent filter.
Install an in-line filter between the
pneumatics and the inlet.
Missing Peaks
Baseline or background
present
Column is broken
Replace the column.
Column flow is incorrect
Make sure the septa are sealing. Make
sure vacuum compensation is turned on.
Backflush settings are
incorrect
Set backflush to
off
until after injection.
Column position in
S/SL injector is incorrect
(too high)
Check the position of the column.
No baseline or
background present
Poor or missing electrical
connection
Check the cable connections.
ISQ instrument is not
collecting data
Make sure the tune file is correct.
Verify that the Busy light is on during
acquisition.
Close Xcalibur, open Instrument
Configuration, press the
Reset
button
on the ISQ instrument, wait ten
seconds, close Instrument
Configuration.
Table 3.
Troubleshooting Peak Issues in Your Data, continued (Sheet 3 of 3)
Behavior
Characteristic
Cause
Remedy
Summary of Contents for ISQ
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