Gangula:

When you say 'denature' I assume you're referring to a protein. A protein is a polymer of amino acids, folded up and held that way via weak Hydrogen bonds. In that case, sonication can indeed destroy a protein's quaternary, tertiary, and even secondary structure. But, this is only because these structures are (generally) formed by relatively weak Hydrogen bonds. Sonication can't normally break up a protein's primary structure because that structure (the amino acid sequence) is constructed of covalent bonds which are many times stronger than Hydrogen bonds and sonication can provide the energy required to break those bonds.

If you're referring to a dried, un cross linked (non amino acid) polymer, a similar analysis applies. The primary structure of the polymer will survive sonication because of the strong covalent bonds. But, if the polymer is already cross-linked, sonication cannot break down the cross-linking. Again, cross-linking bonds are (normally) covalent.

Of course, sonication cannot overcome the solubility limit of a solute in a solvent. Think; are you sure you're not at the solubility limit of the compound? Is the solubility for that compound in that solvent documented somewhere? Do some research and find out the solubility limit if possible.

Don't forget! Sonication typically heats the solvent. You're dumping energy into it after all, so watch your temperature! If your compound finally dissolves, is it because of the increased temperature caused by the sonication? Perhaps simple mild heating will get the job done.

I hope this helps!

Gangula:

When you say 'denature' I assume you're referring to a protein. A protein is a polymer of amino acids, folded up and held that way via weak Hydrogen bonds. In that case, sonication can indeed destroy a protein's quaternary, tertiary, and even secondary structure. But, this is only because these structures are (generally) formed by relatively weak Hydrogen bonds. Sonication can't normally break up a protein's primary structure because that structure (the amino acid sequence) is constructed of covalent bonds which are many times stronger than Hydrogen bonds and sonication can provide the energy required to break those bonds.

If you're referring to a dried, un cross linked (non amino acid) polymer, a similar analysis applies. The primary structure of the polymer will survive sonication because of the strong covalent bonds. But, if the polymer is already cross-linked, sonication cannot break down the cross-linking. Again, cross-linking bonds are (normally) covalent.

Of course, sonication cannot overcome the solubility limit of a solute in a solvent. Think; are you sure you're not at the solubility limit of the compound? Is the solubility for that compound in that solvent documented somewhere? Do some research and find out the solubility limit if possible.

Don't forget! Sonication typically heats the solvent. You're dumping energy into it after all, so watch your temperature! If your compound finally dissolves, is it because of the increased temperature caused by the sonication? Perhaps simple mild heating will get the job done.

I hope this helps!

Thank you Patrick Sir for very clear and elaborate explanation. Thanks Lopez for your reply. I was not trying to dissolve a protein or a polymer. I was trying to dissolve a compound called Bisphenol A in phosphate buffer (0.1M, pH6). The solubility is increasing to some extent by leaving the system undisturbed for a day or two. Sonication for about 2 hours is completely dissolving the substance. My concern is whether the compound will still retain its chemical structure ? As Patrick sir pointed out will mild heating a better alternative or is there any other approach ?

Your responses were very useful. I could get so much information. Thank you very much and awaiting your reply.

Gangula:

No, you don't need to worry about sonicating bisphenol A. Solubility is only about 200 ppm at room temperature, so keep an eye on that. Since the compound is a phenol, you should be able to warm the aqueous solution without danger to the molecule. The boiling point of bisphenol A is about 220 C, so the vapor pressure should be quite low, even at elevated temperatures in aqueous solution. You won't have to worry about evaporation changing concentration.

On the other hand, sonication is working for you now. So, as it's said: "don't fix it if it aint broke."

I have experienced the case of polymers as Patrick Bisson stated. Not only the heating effect but also the mechanical vibration may cause rupture in the molecule specially if a hetero-atom exist, which eases the rupturing. Also, had experience with industrial sector who suffered from quality operation, and the deterioration of herbicidal products passing though windmill. Overall, sonication can suffer (denaturing, causing rupture, etc.,) depending on the type of system you work with.

It,s depends upon the nature of the compound. We cannot say that all the compounds will stable while in sonication. The compound which is not stable in micro wave irradiation, that will denature while sonication....

Yes, it is depends upon the nature of compounds, frequency of waves and duration of expose also.....

Sonication can change both the physical and chemical state of a compound as a result of the hotspot heat energy generated by the frequency of the wave motion. This hotspot do initiate implosion effects on the compound molecule with consequent departiculation or ionization or charge transfer. This may cause the denaturing of the affected compound.