detector

[HW Mueller]

miumiu,
Karen gave you the most likely cause: precipitation. Do a systematic check.

unmgvar, what is HgH and how did you get it to precipitate in the cell? You said proteins (plural) above, others did this? Are you doing HIC? The concentrations are extremely high?

[unmgvar]

simple Human Growth Hormon HW

[HW Mueller]

I worked with growth hormone (mol. wt ~22000) many years ago, don´t recall any problems, didn´t even see any association which many people claimed at the time. It seems a matter of how one handles it.

[unmgvar]

it was the diagnosis and solution decision of Waters.
they came to the conclusion that the things we do with the UHPLCs H-class required the change
especially since the detectors went blind and the flow cells needed replacing anyway.
and remember what I said, no problem with the Alliances there, and no it is not a problem of how we handle the UHPLCs themselves.

anyway it simply comes to show you that you need to know many aspects of your hardware down to those details.

[HW Mueller]

I was referring to handling HGH, not equipment.
Also, if miumiu has a precipitation problem it is most likely not due to wrong or faulty equipment, but rather wrong mobile phase or sample mishandling.

[unmgvar]

no the problem is not with the HGH itself since it was injected in parallel with on a alliance system and the H-class to show make sure this was not an issue
and yes we know that in certain cases when not handle right the stuff can and does precipitate at the bottom of the vial, but it was again seen that this was not the problem

my point in this is not to say the equipment might be faulty
i do not claim that it is.
it is more precise to see this as a case of unsuitable.it has a very different meaning for me then wrong or faulty.
sometimes we do things that are unappropriated to the equipment, while not aware of it.