Im trying to manufacture nanoseeds using microfluidics however the metastable zone width is so wide its difficult to achieve the best conditions with a suitable antisolvent.
Im using citric acid but this applies to any small organic substance with a wide metastable limit. The high solubility of citric acid is also a problem.
My question is to do with antisolvent selection. I've tried preparing saturated CA solutions in water and ethanol and just added dropwise lots of different solvents until precipitation. however none of the 14 solvents ive used has worked up to a antisolvent ratio of 5x. I mostly used short chain and branched alcohols and some other common solvents. Anisole has done something however its pretty harsh on the microfluid chip.
There are so many other challenges to do with CA like its high solubility creating very viscous solutions which lowers its propensity for nucleation and crystal growth. And when crystals begin to form the whole lot goes quickly into one big mass (its very sticky) when I need small evenly distributed crystals.
Any tips would be appreciated.