I have prepared Iron oxide nanopwder suspension in DI water. I want to go for DLS measurement.Should I centrifuge it before measurement ?
You'll change the distribution by centrifuging it..... Iron oxide is dense. What is the SSA of the powder? Are the particles in free colloidal suspension? Do they settle? Have you performed a Stokes' Law calculation to see what sized material will stay in suspension? How have you stabilized the system? See:
Nov 11th, 2008. Dispersion and nanotechnology http://tinyurl.com/hpywsge
no you should not centrifuge them, DLS is based on laser reflection from the suspended particles so you need to vortex your sample too ensure good distribution and not centrifugating the sample.
It is better not to centrifuge the sample before DSL measurement but if you go for centrifugation then it would be necessary to vortex the sample in such a way that all the particles are well dispersed visually.
If there is significant settling then it’s not a DLS experiment but a laser diffraction one....
Generally, before using DLS, it would be better to use a precise number-µm whatman filter to have a narrower range of particle size (particle distribution size) (this technique is quantitative), or technically, by centrifuging in the exact rpm and temperature, you will change the distribution size, however, this technique is qualitative rather than quantitative.
- Badges
- Science topic
- Similar topics
- Chemistry
- Nanotechnology
- Nanoparticle Research