GC doubts

[sankie]

Hi friends,
I am doing some validation works in my GC.
My problem is, I cant complete my linearity studies as there is a major changes in RT and also in RSD.
what may be the problem and how to solve it?

[Hornet]

Hi friends,
I am doing some validation works in my GC.
My problem is, I cant complete my linearity studies as there is a major changes in RT and also in RSD.
what may be the problem and how to solve it?

Hello, you need to tell us what are you trying to analyze and the instrumental conditions (temp.prog, detector, injection technique, column, flows, etc) before anyone can help you.

[chromatographer1]

Davide is correct.

So many posters think they can get good answers merely stating they have a problem with their results and then expect a reasonable useful answer from almost no information about what they are doing.

It is like going to a doctor and telling him you have a pain and want it to be healed without giving any other information.

change in retention time ? by 0.02 min or by 0.2 min or by 1 min?

RSD of levels in a linearity plot ? at high levels or at low levels ? How much analyte are you putting on the column at each level, and how much is injected in what solvent or gas mixure?

And this is only the tip of the information that may be needed to solve the problem.

Sankie, please be more helpful if you really want help.

Rod

[sankie]

Sorry for that guys,
I am doing the development for Xylene and methanol
using nitrogen as mobile phase and 1:10 split ratio
RT changes from 3.7 to 3.9 or 4.1
RSD comes 0.98 sometimes and using the same conditions, it changes to 0.8
What to do?

[Johnny Rod]

What concentrations? How are you injecting? Autosampler? What injection volume?