Hello all! I have synthesized hydroxyapatite nanoparticles and have to characterize them with DLS and SEM analyses. Can someone please let me know the sample preparation methodology for DLS and SEM characterization? Thank you!
Hello Gayathri Natarajan,
why do you have to apply DLS and SEM?
Did you get an instruction or are these the only methods available?
Are you familiar with these methods?
Which information do you want (have you been told) to get?
Size? --> DLS, SEM (maybe), TEM?; but the numbers may differ. Do you have an idea about the size of the particles?
Composition? If < micrometer: EDS in TEM.
Powders may be observed in SEM without preparation (on carbon tape, blow away the loose particles).
Hello Stefan. I have to measure the size of the synthesized nanoparticles for which I want to do DLS and SEM analyses. I am not familiar with these methods and hence wanted to know the sample preparation steps involved for these tests. Thank you for the SEM sample inputs. Is there any specific solvent that you recommend for the DLS method and if so, what could be an optimal concentration for dispersing the nanoparticles in the solvent? Please let me know. Thank you!
Gayathri Natarajan I assume that you have not dried your particulate system. If you have then it's a laser diffraction (not DLS) experiment for particle size distribution. This is because powders contain no free, independent discrete particles < 100 nm but rather are a collection of sub- and post-micron tight aggregates and loose agglomerates. The international standards (ASTM and ISO) recommend a concentration ladder in order to highlight adequate scattering (concentration too low) or multiple scattering (concentration too high). A good starting point is a faint milkiness or appearance of the system. For further details please view this webinar (free registration required):
Dispersion and nanotechnology
https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W190528DispNanoMat
Further information on aggregates/agglomerates etc in:
Adhesion and cohesion
https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W180725AdhesionCohesion
Hello Alan. Thank you for your inputs and the resource materials. They were helpful!
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