HT2800T_en_c.doc Page 228 of 275
8.19.1.6 Faulty temperature read-out
Possible causes
Solutions
Probe or sensor of the syringe
holder temperature are broken
Contact your service representative.
Probe or sensor of the oven
temperature is broken
Contact your service representative.
8.19.2 Analytical troubleshooting (Liquid Mode)
8.19.2.1 Reproducibility issue
Peak area or peak retention times are not reproducible.
Possible causes
Solutions
Injection Depth
Ensure the needle is set to the correct depth for the GC. This is
particularly important if the unit has just been installed or moved.
Leak in the inlet septum If there is a leak in the septum, change it. If the septum had experienced
less than 100 injections, check the following elements to avoid premature
septum problems: the syringe needle is not straight; the septum retainer
nut is too tight; the syringe has not been installed correctly.
Syringe is dirty or worn If there is dirt in the syringe or the plunger is sticking, clean the syringe
according to the manufacturer's cleaning instructions.
Sample volume in the vial is not
correct.
If the sample vial are not filled correctly, evaporation or contamination
can alter the results. The vial should only be filled up too half way (see
paragraph 3.7.1).
The vials are not closed
properly
Check the caps of the vials. Loose caps may cause volatile solvents to
evaporate and change the sample concentration over time (see
paragraph 3.7.2).
Sample instability
Check the stability of the samples,and ensure they are not sensitive to
light or heat.
Sample size variation Change the syringe (syringe is probably imprecise or worn) . For
example syringe with removable needles can cause dead volume
formation or needle to needle variation
Air bubbles inside the needle
Try to modify the following parameters: fill speed, injection speed,
viscosity delay etc... (see paragraph 5.2.2). If the samples is viscous you
can dilute it in a proper low-viscosity solvent.
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