LCMS column pressure

Hi

What mobile phase you are using.

When you are purging the system by opening purge valve of pump that time pressure stable or not.If pressure stable then close this purge valve.

After that autosampler valve to put in bypass mode from masshunter chemstation then see pressure stable or not.

And last remove column and connect capillary tubing with union to see pressure stable or not to identify column is clogged or not.

thank you for your reply.

I am using mobile phase A 20mM NH4OAc/Milli Q water and 100% Methanol mobile phase B.

when I upload the method with which I am supposed to run my samples. In the start, the pressure goes up and then stabilizes, when all the parameters become ready.

Would it be possible to regenerate the column if the problem persist?

Without column, it's stable or not.

If without column, it's stable then column has some problem.

And pressure fluctuates then chances that pump has issue.

May be frit of purge valve. Or pump head.

You can condition the column after passing small amount of mobile phase for 4 to 10 hour..

https://community.agilent.com/technical/lc/w/wiki/7775/general-column-regeneration-procedure

You can follow above procedure to regenerate the column if problem persist with column.

of course when there is no column then pressure is normal. 

when I upload the method, I give some time for the mobile phases to flow through the column and the rest of the parameters such as column temperature, pressure, flow rate to reach up to the suggested value, then I start the run. the problem starts after the run. I am still working on it whether the problem is with y samples or something else is going on. I am working on PFAS and only using standards at the moment.

of course when there is no column then pressure is normal. 

when I upload the method, I give some time for the mobile phases to flow through the column and the rest of the parameters such as column temperature, pressure, flow rate to reach up to the suggested value, then I start the run. the problem starts after the run. I am still working on it whether the problem is with y samples or something else is going on. I am working on PFAS and only using standards at the moment.

Then you can regenrate the column by following procedure i shared previously in reply.

Looks like instrument okay..

I have one question:

Does problem starts when needle take sample and then after sit on kneedle seat to inject it in autosampler?

well, thank you so much for guiding me. I will keep you updated.

yes, It does. when the run starts and it says injecting, right after that pressure goes up, and the run stops.

Yes.

It means problem is with autosampler.

High chances, kneedle seat is blocked..

Needle may be blocked.

Becoz, when sample going to inject through kneedle seat then problem startes..

https://community.agilent.com/technical/lc/w/wiki/7693/backflushing-the-needle-seat-of-the-agilent-vialsampler

You can check above steps.

Hope, problem will solve..