Title: Help Needed: Sodium-L-lactate Not Fully Dissolving in Water
Post:
Hello everyone, I've been conducting some experiments with Sodium-L-lactate in the laboratory. However, I've noticed that no matter how I try to dissolve it in water, I can't seem to fully dissolve it. According to the theoretical solubility calculation, each gram of Sodium-L-lactate should fully dissolve in 3 milliliters of water, but I can't achieve this in practice.
I've tried dissolving Sodium-L-lactate under different temperatures, pH values, and agitation conditions, but still can't get it to fully dissolve. I've also checked for any impurities in Sodium-L-lactate, but didn't find any obvious issues.
So, I'm reaching out to ask if anyone has any ideas or tricks that could help me fully dissolve Sodium-L-lactate in water? I would really appreciate your help!
Thank you!
Lactic acid, and by extension sodium lactate, may be contaminated by oligomers of lactic acid / lactate, which form by condensation with loss of water. The salts of such oligomers are almost certainly less soluble than the monomeric sodium lactate.
You can figure out whether this is the problem by quantifying the sodium content of the material. Less sodium than expected would point to significant presence of oligomers. (C-13 NMR should also be helpful.)
One way to minimize the likelihood of oligomer presence is to start with a commercial lactic acid solution of moderate concentration, e.g. 20-30% rather than the common 70-85%, and to make your own sodium lactate solution by neutralization (to pH ~8-8.5) with NaOH. Titrate slowly with good stirring and cold water cooling.
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