117
5.1 Trouble shooting
5
Presence of ghost
peaks
Septum purge is not being
supplied.
Supply septum purge.
Peaks of previous analysis
appear.
Increase column oven
temperature to the analysis
maximum temperature to
eliminate the sample remaining
inside of column.
Sample is contaminated. Prepare new sample.
Microsyringe is dirty. Cleanse the microsyringe, or
replace it with a new one.
Carrier gas purity is low. Replace carrier gas with one of
higher purity. Provide molecular
sieve filter in carrier gas flow
line.
Substances of high boiling point
accumulated at column inlet
end are flowing out.
Condition columns.
Injection port is dirty. Clean or replace the glass
insert.
Refer to "4.6 Glass
insert" P. 91.
Tubing and pressure governors
are contaminated with oil, etc.
Replace tubing, pressure
regulator, etc. with clean ones.
Septum fragments are present
inside of glass inserts or
columns.
Remove the fragments.
Cleanse or replace the glass
inserts. Break off the tip of
capillary column.
Abnormal peak shape
(e.g. asymmetrical
shape)
[Leading]
The peak arises slowly.
The peak front is
larger.
[Tailing]
It takes very long time
for a peak to dissolve
to the baseline level.
The peak tail is
dragged out.
(In case of Leading) the column
is overloaded.
Dilute sample.
Decrease injection volume, or
increase split ratio.
Change the film to thicker one.
(Divided peak top, leading, or
tailing) Multiple peaks are not
completely separated and
merged into one peak.
Decrease column oven
temperature.
Replace columns to obtain
better separation.
(Leading, or tailing)
Injection port temperature is
low.
Increase injection port
temperature.
(Tailing)
Columns are contaminated.
Condition columns. Refer to "4.8 Packed
column" P. 96 and
"4.9 Capillary
column" P. 97.
(Tailing)
Glass insert is damaged.
Replace the glass insert. Refer to"4.6 Glass
insert" P. 91.
(Tailing)
Septum purge is not supplied,
or is too low.
Supply septum purge.
Increase septum purge flow
rate.
Refer to "3.3
Analysis using
capillary column" P.
49.
(Tailing)
Septum fragments are present
inside glass insert or column.
Remove the fragments.
Cleanse or replace the glass
inserts.
Break off the tip of capillary
column.
Problem Possible cause Solution Reference
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