HPLC baseline is not stable

[khalidniazkhan]

Dear Friends,

We have Sykam germany HPLC with uv-vis detector and calrity software. The mobile phase are D.I water and ethanol. We have problem with our HPLC. The baseline is not stable. At detector display the detector signal is 00 (means OK) but in software the baseline is not stable. We have changed the mobile phases with fresh one, checked the column and have found it OK. Please be so kind to suggest us some best solution to make stable the baseline. What factors involve in an unstable baseline? we are new user of HPLC and does not know much about HPLC.

An earliest response in this regard is awaited.

Many thanks & best regards
Khalid

[DR]

What kind of column are you using, has it been used a lot?
How old is your lamp, how many hours has it been on?
What wavelength are you monitoring?

[Consumer Products Guy]

Turn off the pump, wait a few minutes. Measure the baseline. If more stable then, it's pump-related.

[danko]

Most important action in this case is viewing and interpreting the baseline.
Show us the problem.
Unstable baseline is many things

Best Regards

[khalidniazkhan]

Hi,

Thanking you for the kind support.
We are using column C18. and it is almost new. The detector is used since last 3 years. no lamp of the detector has been changed yet. The wavelength is 254nm.

Please let us know if you need more information about our HPLC.

Many thanks

Khalid

[danko]

Post the plot - baseline so that that we can see it.

The column is absolutely irrelevant in this case.

Best Regards

[DR]

The detector is used since last 3 years. no lamp of the detector has been changed yet.

So, the lamp is a minimum of 3 years old? See if you can find another lamp to try.

[KVVENKATARAO]

Dear Friends,

We have Sykam germany HPLC with uv-vis detector and calrity software. The mobile phase are D.I water and ethanol. We have problem with our HPLC. The baseline is not stable. At detector display the detector signal is 00 (means OK) but in software the baseline is not stable. We have changed the mobile phases with fresh one, checked the column and have found it OK. Please be so kind to suggest us some best solution to make stable the baseline. What factors involve in an unstable baseline? we are new user of HPLC and does not know much about HPLC.

An earliest response in this regard is awaited.

Many thanks & best regards
Khalid

Dear friend,

In the mobile preparation you take precaution of sonicate to degas are not, in the mobile phase preparation, i think your not mix water and ethanol properly & this mobile is take half-an hour for system stabilization purpose.

Thanks and regards,
K.V.Venkata Rao

[daniel_aut]

Change the lamp(s), clean the flowcell(per user manual) and when the system is "spotless" run methanol(with a flow restrictor, low flow) and measure the baseline.You will not have OQ limits but pretty damn close.
Good luck.