Asante Ca2+ Red low affinity

[Pieter de Tombe]

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Hi All,

Does anybody know what happened to the Asante dyes ?

In particular I am looking for Asante Red low affinity Ca2+ dye .. what is attractive is that it is possible to make ratio-metric measurements.
I am trying to measure free Ca2+ in EGTA buffered solutions in the 10uM or so range .. the free salt of Asante Ca2+ red low affinity would allow that with 488nm excitation and dual wavelength emission measurements.

But finding a source to purchase this compound turned out to be difficult, if not impossible.  It was sold by Teflabs, but they may be out of business.

Any alternative dyes anyone  could think of that could be used (ratio metric is preferred; signal brightness not so important, I can always use more indicator dye ,, these are bulk solutions) ? ...

Thanks,

Pieter de Tombe
Univ. of Illinois at Chicago