Why are the peaks of methanol, ethanol, and isopropanol that I obtained using gas phase separation separated from each other?
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Why are the peaks of methanol, ethanol, and isopropanol that I obtained using gas phase separation separated from each other? The three peaks of theirs are connected; before even returning to the baseline, the next peak begins to form. The injection port temperature was set at 170, and the detection port temperature at 180. Various temperatures were tried for the column temperature: initial temperatures of 40, 50, 60, 70, 80, 90, and 100, as well as various heating programs, but none of these yielded satisfactory results. Another issue is that even for the samples I analyze, the peaks resulting from them are quite wide, and there’s often tailing as well! Please help answer this! Thanks!
You can try using programmatic temperature elevation; this is due to poor separation efficiency. If your peaks are tailing, it may be caused by two reasons: 1. The column temperature is too low； 2. Incorrect column selection
You can also try instant non-diverted injection
Firstly, the peaks of methanol and ethanol are somewhat difficult to distinguish from each other. Additionally, the tailing phenomenon might be due to the reason mentioned by Haiyou on the second floor; let’s discuss this together
That’s right; dilute the solution further so that there’s less of it
If the peaks do not separate, it indicates that the separation effect is poor. You can try using programmatic temperature control, and it is also crucial to find an appropriate chromatography column
Try reducing the flow rate or increasing the column temperature; also reduce the injection volume. In the case of capillary columns, the installation of the column can sometimes play a role as well. We can only use the process of elimination.
What kind of columns are used? Swap the columns
I think the column you’re using is generally not the right one; I’ve tried using methanol and ethanol, and with non-polar columns separation isn’t possible – polar columns such as PEG-20M are needed to achieve separation. Give it a try; if you use a non-polar column, no matter how you change the conditions, they won’t be separated.
There is a book in the reference section: Atlas of Applications in Gas Chromatography. Go and check it out; it contains detailed answers. First, download it and then use the search function – just enter \"ethanol\". It can be found on page 95