Weigh accurately about 0.1g sample in a beaker. Add 2 to 3 drops of diluted tween 80( 1ml in 10 ml of water). Make a homogeneous paste with the help of spalula or glass rod. Add 25 ml of distilled water and sonicate extemally for 2 minutes to avoidd sinking of sample to the bottom of the beaker. Take out the sample from sonicator this avoid agglomeration. Now sample is ready for measurement.