Trichloro acetic acid.. Safe as TFA?

[pipettemonkey]

The proper question here is-

If TCA happenes to be locally well-stocked, will it (completely) substitute for TFA in reverse phase HPLC? TFA has a slightly lower pKa, but for this application, they are effectively equal).

[Kostas Petritis]

I do not really see why someone would like to use TCA instead of TFA as the latter is volatile and available in very high purity.

I had once a conversation with someone who was claiming that he sees alternative selectivities when he was using TCA instead of TFA but I never verified it.

So... the proper answer is... you can always try (if your TCA is pure enough for HPLC applications) but it does not mean that you will observe the same results... May you can let us know if you observe any selectivity differences if you decide to compare them...

[pipettemonkey]

Thanks for the reply.

The TCA is of HPLC purity.. I agree that normally TFA is the preferred buffer.. In this instance, high purity TCA is abundant, of good quality, and on hand. I'm mostly concerned with how it agrees with the hardware compared to TFA.

[DR]

As long as you aren't feeding it to MSDs, it should be OK for the equipment. I would expect some changes in selectivities...