Problem finding suitable pH 9 buffer


Hi everyone,
I'm new here and decided to get online to glean some info from those of you with experience/expertise in buffers.

I'm trying to find a buffer for pH 9 that will neither bind Cu2+ nor Zn2+, nor be included in beta-cyclodextrin, nor be insoluble in water at 25deg C. I'm making up solutions for UV-Vis analysis to determine the kinetics of ester hydrolysis reactions.

So far almost all of the buffers I've found contain primary or secondary amines (which will interfere with Zn-binding), bind to Cu2+, or have very low water solubility. (And I'm trying to avoid HEPBS which is $291 for 25g!)

This buffer is pretty much the only thing standing between me and finishing my PhD, so I'd greatly appreciate any suggestions anyone might have! Thanks!




A lot depends upon what you are needing it for but if you look on the internet you should find a universal buffer that you can alter to suit, sorry I am not at work at the moment, it being the summer holidays and I can't remember off the top of my head what is in them (not much help I know) but try looking up 'universal buffer' and you might find what you need.


Thanks very much for your help :)

Unfortunately I've found that a lot of the Universal Buffer compositions involve either one of Good's buffers (which bind either Zn or Cu or both) or boric acid/borate and zinc borate has >0.3% solubility in water (the solvent I have to use).

I did find a good artciel about synthesising non metal binding buffers based on Good's buffers if anyone's interested though (seems like this should be a major issue for a lot of biological/physiological studies!) -

"Avoiding Interferences from Good's Buffers: A Contiguous Series of Noncomplexing Tertiary Amine Buffers Covering the Entire Range pf pH 3-11" Analytical Biochemistry 253, 50-56 (1997)

Thanks again.