[emily5151]

Hi all,
I have a question that needs your help with.

What changes would you expect to observe in the relative location of the butene peaks if you were to
a. Increase the flow rate of the helium carrier gas?
b. raise the temperature of the column to 40 C above room temperature?

I've done some research. I think for a,the condition will reduce band broadening because of quicker molecular diffusion. Therefore, sharp beaks will be observed.
For b, the peaks will be very close to each other because the solutes will be eluted faster.

Can anyone correct me?
Thank you. Any help is appreciated.

[marcal]

I believe you´re correct. With such small molecules, peaks will appear sooner. As a consequence, if you have, for instance, different isomers of butene, they will appear closer to each other.

My personal rule when working with GC is to calibrate, no only for any new conditions and products, but also in regular intervals. For example, if I have to spend one week measuring, I will calibrate for my particular case before I start. If it has been relative long since I measure last, even in known conditions, I calibrate before I start. It doesn´t take long and it keeps you problems-free, most of all if you´re working on a shared device.

Take what I tell you with caution. I´m not an analytical chemist!

Hope it helps.