Which type of nanoparticles you are synthesizing at such high temperature ?

It depends on the constitution of the extract,the low m.p. components are affected but components with high m.p. are not. There is another probability which is oxidation of the metal if it is photosensitive like Silver, Zinc ...etc

If this degree is not necessary in your case, do it at lower temp. 80 0C

OKAY doctor, appreciate your answer so much

You are welcome.....Good Luck

Which type of nanoparticles you are synthesizing at such high temperature ?

could you clearly mention the type of nanoparticle being synthesized? Usually higher temperatures are not preferred in green synthesis. But can depend on the material to be synthesized and solvents used.