Injection and/or detection problem????

soraiasa · November 5

I am having a problem with injection and/or detection, I guess.....When I inject the same solution with a known concentration 6 times in a row (after a solvent), the first one does not show any peak signal and, while the other 5 have reproductable signals. After this batch I inject another solvent and I have the same signal as the previous 5 injections of the known standard, as you can see in the table below. Considering this behaviour, I think it is some kind of delay in injection or detection?? Can you help to understand which can be the problem??? Does anyone already had the same problem??

Thank you

Image: https://us.v-cdn.net/6030142/uploads/editor/4k/1mbxa97ebavf.png

Dan_Ramlose · November 6

First thing to check is whether your peak is really eluting at ~2min.
Set your run time to about 6 min and confirm this. If my suspicion is correct, your real RT is between 4 and 5 min.

Injection and/or detection problem????

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