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Offset problem of retention time
Posted:
Thu 23 Jun 2016 12:12by James Bondd
Hello,
I have installing a new GC column, and my retention time of analytes have really change a lot and I don't understand why? Could you help me?
Bondd, James Bondd
Re: Offset problem of retention time
Posted:
Thu 23 Jun 2016 15:20by Christy
Hello James,
Most likely a retention time shift like is due to dimensional differences in the old and new columns. Your previous column was likely trimmed during inlet maintenance and so your new column is likely longer than the old one. The length can be up to 1 meter longer than the nominal length.
Here are some suggestions to minimize this effect :
1. If the GC has electronic pressure control (EPC), the best way is to enter the actual column diameter into the software. This actual measured value for the diameter is reported on the Performance Summary Sheet that came with the column. By inputting these values, the ECP will make adjustments to the flow to compensate for any differences in diameter.
2. If you ever trim the column you will want to report the new length to the software as well so that the EPC can compensate.
Hoping to have helped you
Christy
Re: Offset problem of retention time
Posted:
Fri 24 Jun 2016 09:24by James Bondd
Hm... Thank you Christy
Bondd, James Bondd