Noisy baseline even without flow cell

[cougar]

Agilent 1200 with DAD. I got noisy baseline on it. First I tried stopped the pump, the noise kept the same level. Then, I pulled the flow cell out and found the same noisy baseline. Please help me and give some opinion or suggestions about it! Thank you in advance!

[danko]

It's all about defining noise, or in other words, degree of zoom. If you zoom in enough you will see noise - no matter what. On the other hand, if you zoom out enough you will find the noisiest baseline completely plain

To be more concrete: You might like to describe the issue/noise using numbers - absorbance units or Volts or whatever.

Best Regards

[cougar]

Thanks for your reminding. The noise level is between 0.1 - 0.2 mAU (with setting 1 AU = 1 V). It's a little bit high when doing impurity profiling.

[danko]

OK, not huge noise but not noise-free either.
The question now is whether it has been like this since the birth of the equipment you have or it’s something that happened over time – maybe last couple of weeks or something.
If it always has been like this you could try playing with the detector/software settings – i.e. Reduce the sampling rate and/or use the smoothing function.
If you’re used to see much less noise and it became worst recently (without you changing anything of importance), it could be the lamp – needs replacement.

Best Regards

[cougar]

Thank you very much, danko!