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- Posts: 1
- Joined: Fri Mar 20, 2020 1:27 pm
Hi all,
I'm not adept at solving GC problems, so I would like to ask for advice.
I installed a used column Zebron ZB-WAX (4 weeks stored in the dark, the ends were stuck in a rubber), with new fittings, new cut (approx. 4 cm). After N2 washing, I analyzed five blanks – hexane and the baseline and peaks of standards was good. Unfortunately, I had a problem with the software, so I reinstall the Clarity soft. It took one week to solve the problem with the software. Subsequently, I wash the column by N2 (60 min) and analyze hexane five times and the baseline start to be wavy and increase during temperature gradient. I'm sending the picture of the old chromatogram (was good) and the new one. The temperature of the gradient was subsequent: int 70 °C- hold 4 min, 15°C/min to 160 °C and 3°C/min to 240 °C. The baseline mainly increases in the gradient 3°C/min to 240 °C. Moreover, there is a small second peak next to the solvent peak.
I tried to fix it and clean the inlet. In the gold inlet seals, I found some impurities. Maybe it could be a graphite ferrule? Anyway, I cleaned inlet, cut column on the inlet and installed new graphite ferrules. Unfortunately, the baseline problem is still the same.
Now, the question is.. it is column bleeding? Or any other impurities? Should I trim the column approx. 20 cm? Unfortunately, I don't have a leak detector or column solvent washing equipment.
Thank you for your help
Sylvie
https://ibb.co/rmj8RWD
https://ibb.co/nmkHr2J
I'm not adept at solving GC problems, so I would like to ask for advice.
I installed a used column Zebron ZB-WAX (4 weeks stored in the dark, the ends were stuck in a rubber), with new fittings, new cut (approx. 4 cm). After N2 washing, I analyzed five blanks – hexane and the baseline and peaks of standards was good. Unfortunately, I had a problem with the software, so I reinstall the Clarity soft. It took one week to solve the problem with the software. Subsequently, I wash the column by N2 (60 min) and analyze hexane five times and the baseline start to be wavy and increase during temperature gradient. I'm sending the picture of the old chromatogram (was good) and the new one. The temperature of the gradient was subsequent: int 70 °C- hold 4 min, 15°C/min to 160 °C and 3°C/min to 240 °C. The baseline mainly increases in the gradient 3°C/min to 240 °C. Moreover, there is a small second peak next to the solvent peak.
I tried to fix it and clean the inlet. In the gold inlet seals, I found some impurities. Maybe it could be a graphite ferrule? Anyway, I cleaned inlet, cut column on the inlet and installed new graphite ferrules. Unfortunately, the baseline problem is still the same.
Now, the question is.. it is column bleeding? Or any other impurities? Should I trim the column approx. 20 cm? Unfortunately, I don't have a leak detector or column solvent washing equipment.
Thank you for your help
Sylvie
https://ibb.co/rmj8RWD
https://ibb.co/nmkHr2J
