Hey guys out there, wondering any one of you had the experience in using HEPES buffer? i m having problem in making a HEPES buffer with pH 7.4. After i dissolved my HEPES in the deionised water, It gave me about pH 5.2. Some one has suggest to adjust the pH with either HCl or NaOH. However, Is not it buffer should resist the change of the pH ? any one please advice me on this ? pleaseeeeeee....=)

Better to ask postdocs/others in the lab this kind of question. Yes you need to increase the pH with NaOH. Do you need instructions (pH meter, mixing, etc.)?

i agree that you should ask someone in your lab about this. usually there are protocols and receipes lying around at the lab on how to make certain buffers, as they are used frequently.
but if your pH is 5.2 and you need 7.4 and someone actually suggested using NaOH, then go for NaOH and neutralize your acids. i must say at this point though that i never made HEPES buffer myself yet, so i don't know how exactly you prepare it

Yes, we pH HEPES using NaOH (preferably 10M, added dripwise with a pasteur pipette); if you go over the target pH (try not to) then use HCl. Different buffers may use different chemicals for this purpose, like NaH2PO4, sulfuric acid, citric acid, etc.

As Tydra says there should be protocols laying around. You shouldn't worry about asking questions like this in the lab if you're a student.

no experience of this buffer but just a quick note - have you checked the pH of your deionised water? I think buffers are only supposed to stabilise minor changes, not massive ones, it may be that the water is too acidic at the outset. :$ I'm at home and haven't the relevant books to hand, so if this sounds like complete rubbish for your particular situation, please feel free to ignore! :-)

thanks lot for your reply. yea.. actually i asked around ppl in my lab already and not many staffs for me to refer to because i m working in a newly set up lab. sigh... i know it is not a hard thing but it seens so hard to get some sources over here. i even called to the supplier and asked but it is already more than a week after my second call yet no reply from them. anyway, thanks lot for your reply. so the conclusion is i can use NaOH to adjust the pH huh? =)

Hi Chloe
I use a hepes buffered solution in my work also and we routinely use NaOH to adjust the pH back to 7.3-7.4.