uECD signal increase

[frank.lupico]

Hi.
Thats my problem.
During the sequence suddenly the signal in uECD increase.
Sometimes one injection is on 300 Hz and next incjection running in 500 Hz.
Sometimes the signal suddenly increase from 300 to 500 Hz during the one incection/analysis.
Its shows in attached chromatograms.

Code: Select all

http://s000.tinyupload.com/?file_id=03294320583173885096

Code: Select all

http://s000.tinyupload.com/?file_id=09155856303246386258

I replace: ferrule from the detector side, ferrule from the injector side, column, liner, septa, traps on hel and nitrogen.

Where is the problem? Does anyone have an idea what is going on?

My GC: Agilent 6890N

Thank you for any help, tips.

Frank

[James_Ball]

Hi.
Thats my problem.
During the sequence suddenly the signal in uECD increase.
Sometimes one injection is on 300 Hz and next incjection running in 500 Hz.
Sometimes the signal suddenly increase from 300 to 500 Hz during the one incection/analysis.
Its shows in attached chromatograms.

Code: Select all

http://s000.tinyupload.com/?file_id=03294320583173885096

Code: Select all

http://s000.tinyupload.com/?file_id=09155856303246386258

I replace: ferrule from the detector side, ferrule from the injector side, column, liner, septa, traps on hel and nitrogen.

Where is the problem? Does anyone have an idea what is going on?

My GC: Agilent 6890N

Thank you for any help, tips.

Frank

Did you replace the large ferrule on the makeup gas fitting to detector? We have had those crack before and leak as the oven temperature ramps up, or just give erratic readings.

Also the liner inside the makeup gas fitting can break or become contaminated and cause problems.