Second Calibration not appearing

[cchan_21]

Hello,

I was wondering if anyone has had this happen before?
I have noticed some differences with my injections. Despite the first calibration peaks all showing up, I found that after I ran all my samples, the second calibration peaks did not show up at all. Also, I noticed that despite I do a urea wash after the samples I inject, there is still a huge amount eluted out (which was never the case, usually its very small peaks), almost looking like the sample injection elution. Please help!

[vijayak]

Hi,
Quick suggestion
Cause 1: Check your injector and try to prime it 4-5 times
Cause 2: If you using agilent system, Check your Rotor seal if possible change it
Cause 3:If it is an auto sampler, remove your neeedl seat and sonicate with IPA

[cchan_21]

Is it possible that an overload of samples may cause the calibration peaks to not appear? Since all the sites on the column have been taken up?