You can high resolution microscope. Now a days some many microscope to determine the particles size even in nanometer to micrometer.

you cannot use SEM because it will be change the phase of the materials I am agree with Md Kamal you can used microscope with high resolution.

for liquids sample taking SEM is quite difficult, since vacuum will be created or N2 gs will be sent, liquid samples should be dried or coated to some conducting plate then only sem is possible. liqid samples some time blocks the electron gun source,leading to malfunctioning of the instrument.

Dear All,

Thank you for your time and response.