HTA HT2000H - Peak Distortion or Tailing; Carry over Issue; Unexplained Chromatographic Peaks; Retention Times Not Repeatable

HT2000H_en_n.doc Page 136 of 167
8.18.2 Peak distortion or tailing
Possible causes Solutions
Method parameters Check all the method parameters, in particular the sample speed, the pull
up strokes (see paragraph 5.2.2.4), the injection speed and the post in-
jection dwell (see paragraph 5.2.2.5).
Needle penetration speed in GC
injector
Check the injection parameters (see paragraph 5.2.2.5).
GC injector liner not suitable Check the liner geometry according to the recommendations of the GC
manufacturer.
GC related parameters Any parameter like injector, oven or detector temperature can contribute
to bad peak shape. Check the column type and connections (square cut
connections). Check the troubleshooting guide of the GC manufacturer.
8.18.3 Carry over issue
Possible causes Solutions
Syringe is dirty Increase the syringe purge time in the method (see paragraph 5.2.2.5).
Set the syringe temperature 10°C above the oven temperature (see
paragraph 5.2.2.3).
None or too low Syringe flush
gas pressure
Check pressure at External pressure regulator during the syringe purge.
Check gas flow at syringe needle tip.
8.18.4 Unexplained chromatographic peaks
Possible causes Solutions
Purge gas is dirty Check purge gas for impurities.
8.18.5 Retention times not repeatable
Possible causes Solutions
Problem in the GC system Check the GC for leaks in the inlet, including septum.
Check the liner type used.