About gas chromatograms
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I use an Agilent 6820 gas chromatograph to measure the methanol content in wastewater, and use a 1ul manual syringe to inject the sample. Why does the resulting spectrum have negative peaks?
Generally, there are two situations when there are negative peaks in chromatography: whether the carrier gas or baseline is suitable. I don’t know if your situation is that things like analysis suddenly appear negative or something else.
Reply 2# bingo999 is that in the spectrum of the sample, a negative peak occasionally appears, and sometimes it is present in each sample, and sometimes it is not. I don't know if it's a sampling problem.
You are directly injecting the amount of methanol. If you use a capillary column, negative peaks will appear due to the high water content (overload).