Unorthodox flow cell cleaning

[nilecroc]

Hi. I have an unusual question for you: is it possible to use a heated cleaning solution(25% phosphoric acid, 70-80 C) to clean a dirty flow cell, provided that all the wetted components resist to this temperature?
We have a Varian HPLC, with a Prostar 335 DAD detector and some service guy suggested me this aproach. Thank you.

[danko]

Did the service guy elucidate the use of 25% phosphoric acid and even more importantly the 70 – 80° temperature? Is it some sort of universal cleaning procedure?
Generally, it’s wise to assess the nature of the pollution one expects to find and wishes to remove. A good angle is to start by tracking the applied/analyzed compounds over time and try to figure out whether or not some fractions of them have built up on the optical parts of flow cell.
My first impression is that the suggested cleaning procedure is a bit harsh.

Best Regards

[nilecroc]

Well, the 25% phosphoric acid at room temperature is the SOP from the detector's manual. I suspect he suggested heating the solution as a tradeoff as oposed to increasing the concentration. A bit harsh, I know. Thank you

[danko]

[/quote]I suspect he suggested heating the solution as a tradeoff as oposed to increasing the concentration.

If increasing the phosphoric acid’s concentration was the only parameter that could be varied, it might have been an idea to warm up the solution. But as mentioned earlier the nature of the pollution/build-up might necessitate another chemical approach – could be alkaline solution or organic solvent or a combination of these or other possibilities.

If you tell us what typically has been loaded on the system, as well as the eluents’ nature some of the guys here might come up with somewhat more concrete suggestion.

Best Regards