Circumstances of HPLC Laboratory

[syx]

I have an example from USP monograph for ubidecarenone. Ethanol anhydrous and methanol are used as mobile phase. So, we should to keep the system still anhydrous when it is running.

The RH of our HPLC room has been checked and the value was between 70%-76%.
Is it safe for the analytical instrument?
Should we make the room drier?

Note: The next door beside the HPLC room is wet lab (any instruments using water-bath: dissolution tester, disintegration tester, rotavapor, etc, are located inside).

Would there be slight change in volatile component (acetic acid, formic acid, etc) of the mobile phase in the reservoir during analysis run in a day due to the circumstance?

[DR]

There would be a slight change, but not a significant change (unless you're running at much higher concentrations of these additives than we are). You should see no discernable change in your chromatography as a result of loss of TFA, acetic acid etc. used at anything approaching normal levels. If there is a change directly attributable to the loss of a couple of ppm of a mobile phase additive, you have some serious robustness problems with your method.

[syx]

Next question, what is the effect of circumstance to the hardware? May the air flow have influence to the performance of the instrument? May corrosion or stain be built up due to high humidity?

Let see this case:
My colleague ever told me about her experience with autosampler in the faculty. They located 2 autosamplers exactly under the air conditioner, and another far away from the air flow, in the same room. The problem was occurred to the last autosampler. It was new. The motor did not move correctly. It stopped after few injections. Then the official technician was called and they told that the problem was caused by heat. The hardware should be located under air flow. Because there is no enough space under the air conditioner, my colleague put a fan beside the autosampler and it works properly until this time.
This case and its troubleshooting are very contrast with what our supplier had told us about the location of HPLC unit. We have different brand with our colleague’s. The sole agent of ours told us that it should be avoided to locate a HPLC unit under the air conditioner or under direct air flow.

Could anyone told us rationale explanation about this?

[Mark Tracy]

The advice to locate the instrument away from the air conditioner was based on experience in temperate climates. People who write such specifications usually don't anticipate that the instrument might be installed in a shack in a cornfield. (No I didn't make up that example.) I have the opposite problem of yours: one of my pumps is right under the A/C vent and I get false alarms from the leak detector.

High humidity can be a problem. Check the site requirements and electrical specifications in your operator's manual.