I think it mainly depends upon if any particular compound you want to extract? Depend upon the solubility you may choose MeOH or water. But if you are thinking for nanoparticle synthesis, I think water extract is enough capable to do that nicely. And the actual intention for green chemistry is to avoid organic solvent, so to me water is the best solvent for that.
Hi Rajesh, it depends on the particle you want to extract because if the material you want to extract temperature sensitive than your product denatured on high temperature, and for economical point of view you use try to start from water, but I use acetone their result are good for oil extraction.
But first do let me know what is the application for the synthesized nanoparticles.
Also, i wud suggest that u start high polarity solvents to the lower ones in case of the solvents like u asked earlier. or you can try with water itself since it universal solvent.
Hi Raj, the best solvents probably are the high polarity like ethanol or mixtures water/alcohol (etanol, methanol), but it depends the application. In other hand, the clasical solvents like acetone or chlorinated solvents are best in many potencial applications.
Water is the best solvent as it is also very compatible and non-reactive.
Check the following book chapter where a clear differentiation of the role of various solvents based on polarity in extraction for NP synthesis is explained.
"M. Sathishkumar, A. Mahadevan, S. Pavagadhi, R. Kaushik, V. Sharma, R.
Balasubramanian, 2013. Biological synthesis of silver nanoparticles and
assessment of their bactericidal activity, In book: Green Sustainable
Nanotechnology and the Environment, American Chemical Society, USA."
I think u want to extract some antioxidants/reducing agents from plants. Plants like tea contain such molecules in abondance. These molecules are soluble in water and alcohols. U may use ethanol as it is easier to remove it under reduced pressure. Methanol is toxic and acetone wont be effective in extraction. water require higher temperature, the antioxidants may degrade at temperatures higher than 50-60 C.
Many solvents are being used for the synthesis of nanoparticles. Eventhough water has found much better one than others, if u want to disperse the nanoparticles in organic solvents like chloroform, dichlorobenzene etc, u have to go through the synthesis using amines like oleylamine and long chain fatty acid like oleic acid. I hope the following link would help u much.
Depending on what class of ccompounds you want to extract you can use a range of solvents. Sequential extraction will extract most phytocompounds from plant material. Start extracting for non-polar compounds with a non-polar solvent like hexane. After maceration for a couple of days, filter the sample and concentrate the extract using a rotevaporator. Thereafter, macerate the residual plant material in DCM for a couple of days. Filter and concentrate the crude DCM extract. Finally, macerate residual plant material in MeOH to give you the polar compounds. So you have 3 crude extracts, hexane extract giving non-polar compounds and fats, DCM extract where you usually find your terpenes and MeOH extract where you can find your polar compounds like flavonoids. You can use all 3 crude extracts to synthesise nanoparticles or isolate the phytocompounds from each crude extract to get pure compounds which you can use for the synthesis.
For plant-mediated synthesis of nanoparticles you would need to reconstitute your extracts or pure phytocompounds in water for a greener synthesis. Hence, it makes more sense to separate the methanol extract on the column to obtain fractions or isolates as these phytocompounds would likely dissolve in water unlike the hexane or DCM extract. Sometimes you might have to acidify or basify your solution before synthesis depending on the solubility of your fractions or isolates
I think it mainly depends upon if any particular compound you want to extract? Depend upon the solubility you may choose MeOH or water. But if you are thinking for nanoparticle synthesis, I think water extract is enough capable to do that nicely. And the actual intention for green chemistry is to avoid organic solvent, so to me water is the best solvent for that.