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- Posts: 1
- Joined: Tue Oct 11, 2011 9:51 am
Hi all!
I work at a medium sized hospital lab. We are performing analysis of alcohol in blood plasma samples – dilute and shoot. Agilent GC 7820 (FID). I have not been involved with setting up this method and it seems to have been in use for many years but the GC-instrument is new. I’m just a techie/chemist who try to fix out of order stuff in the lab (ex. change column) and I have basic knowledge about GC methods. We are continuously having trouble with this analysis. The lab manager says it has been getting more frequent. We are experiencing drifts that makes the RT’s eventually “go out the window”.
Laborating staff do not have the authorization to edit the calibration table. We have had cases where everything is working fine and then suddenly after one sample run (sequence) the ret times shift outside their window and stays there at their new RT’s. This usually happens during weekends when people tend to drink and do stupid stuff and end up in the hospital and no one is here to update the calibration table until office hours on Monday.
Columns (Agilent PoraPlotQ CP7550, 10.00um, 12.5x0.32x0.45) last about 1 month before we have to change it to be able to maintain detection and quantification demands for Ethylene glycol.
Retention times are set manually in the calibration table after running the calibrator a few times. Ex after maintenance (septum/liner/column).
The calibrator is run every sequence + one control sample alternating between high and low control.
Is it possible to make the calibration procedure more adaptive to drifting RT’s without compromising patient safety (misinterpreatation of patient samples)? I could use some input from someone more experienced.
See exported method textfile and example chromatograms here: https://www.dropbox.com/sh/hr57cte2khfs8x6/AACIbGAkpbTdgVgTbkbR1_yda?dl=0
Edit: If it's possible to increase the detection window for the first two peaks (MeOH and EtOH) and keep the default 5% for the rest of the peaks it would really help.
I work at a medium sized hospital lab. We are performing analysis of alcohol in blood plasma samples – dilute and shoot. Agilent GC 7820 (FID). I have not been involved with setting up this method and it seems to have been in use for many years but the GC-instrument is new. I’m just a techie/chemist who try to fix out of order stuff in the lab (ex. change column) and I have basic knowledge about GC methods. We are continuously having trouble with this analysis. The lab manager says it has been getting more frequent. We are experiencing drifts that makes the RT’s eventually “go out the window”.
Laborating staff do not have the authorization to edit the calibration table. We have had cases where everything is working fine and then suddenly after one sample run (sequence) the ret times shift outside their window and stays there at their new RT’s. This usually happens during weekends when people tend to drink and do stupid stuff and end up in the hospital and no one is here to update the calibration table until office hours on Monday.
Columns (Agilent PoraPlotQ CP7550, 10.00um, 12.5x0.32x0.45) last about 1 month before we have to change it to be able to maintain detection and quantification demands for Ethylene glycol.
Retention times are set manually in the calibration table after running the calibrator a few times. Ex after maintenance (septum/liner/column).
The calibrator is run every sequence + one control sample alternating between high and low control.
Is it possible to make the calibration procedure more adaptive to drifting RT’s without compromising patient safety (misinterpreatation of patient samples)? I could use some input from someone more experienced.
See exported method textfile and example chromatograms here: https://www.dropbox.com/sh/hr57cte2khfs8x6/AACIbGAkpbTdgVgTbkbR1_yda?dl=0
Edit: If it's possible to increase the detection window for the first two peaks (MeOH and EtOH) and keep the default 5% for the rest of the peaks it would really help.
