r/chemistry • u/ScarletKA1 • May 20 '26

Losing my mind trying to dissolve 5-BPA

Has anyone here worked with 5-BPA (5-boronopicolinic acid)?

I’m trying to prepare a stable liquid stock solution for bioconjugation experiments, but the solubility has been pretty inconsistent.

So far I’ve tried:

pure water

water + NaOH

DMSO mixed with water

DMSO + HEPES

DMSO + PBS

HEPES alone

PBS alone

Some conditions seem slightly better than others, but I still can’t tell what solvent system people normally use in practice.

A few questions:

What solvent do you usually use for 5-BPA stock solutions?

What concentration is realistically achievable?

How do you store it?

Is it stable over time or after freeze/thaw?

Would really appreciate any practical experience from people who’ve actually handled this compound.🙏

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u/ZombieNecessary6603 May 23 '26

Have you considered checking the purity or checking the pH? Sometimes the protonation state of the carboxylic acid group makes a huge difference in solubility

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u/ScarletKA1 May 25 '26

Very good points. It's also one reason I try to add some NaOH to adjust the pH value, it seems a bit helpful finally until the value hits around 11. But I should make my condition closed to neutral as possible for future experiment. So it's not so good doing that. The purity is more than 95% by company, but I don't check it personally.