Long story short I'm making some nanoparticles and one of the steps require me to evaporate THF(tetrahydrofluran) out of an aqueous solution containing the NP's. This needs to be done under a partial vacuum with only one intake valve(I know, it sucks but I have no other option). I'm looking more for an equation/formula that I could maybe integrate over time because, as we all know, evaporation depends partly on the partial pressure which would increase over time as I only have a single intake valve, however, I'm considering opening the vacuum occasionally once partial pressure reaches a maximum to flush it out. I have no exact number but here are some estimates: Solution- 8mL H20, 2mL THF, negligible NP composition, no stirring, ~1.5cm^2 surface area. Vacuum- ~1L, partial vacuum, surrounded by room temperature. Hope I'm not forgetting anything... Like I said I'm really just interested in a formula and a clear explanation on how to use it in this case.