Jacob Keller wrote:
Dear Crystallographers,
I would like to soak my crystals in bicarbonate (a possible
substrate), but the crystals have grown--and only grow--in pH 5.2-6.0,
so the bicarb/CO2 will just keep evolving out of the solution and
reliquishing its hydroxyls until the pH is elevated sufficiently out
of range. Does anyone have a clever way of getting bicarb into these
crystals? Grow them under CO2? Transfer them to higher pH, and hope
for the best?
Jacob Keller
Assuming they grow by vapor diffusion- how about:
Replace the reservoir with diet coke (Perrier water
if you want to be high class) with pH adjusted to
the range you want and sufficient PEG or glycerol
to give the same osmolarity?
CO2 diffusing in will lower the pH but not much below
that of the reservoir. When you open the well to mount,
especially with hanging drops, the CO2 will leave
and pH will rise, but not above the starting point.
