There are a lot of limitations in DLS. In many cases, samples may be aggregated which dramatically change the zeta potential or particles size determination results.
Well prepared suspension or average of at least 21 measurements is always desired to get a reasonable result. Good luck.
Dear
md.aminul, plz tell me limitations only
What are lots of limitations
Please write ..
@ Md. Aminul Islam Mraci
From where do your comments originate? 21 is half of 42...
You describe sample-dependent features which are the same for any technique rather than any feature of the technique itself.
The advantages of DLS is that it's an ensemble method (billions of particles measured simultaneously together and thus more representative and quantitative than, say, electron microscopy), rapid (results in 30 seconds or less), and very sensitive to small amounts of large material (because of the r^6 dependence in scattering). The disadvantages are that it's not a particle-by-particle analysis (so lower resolution than a system which can measure each particle but would be much slower) and there's no qualitative visualization of the system which is always essential. In combination with (say) NTA, and SEM, then DLS provides the best combination of tools. TEM is only useful in limited circumstances (atomic planes, interfaces) and each and every result is an artifact of sample preparation and selection. No one tool should be used in isolation. NTA provides number based data and DLS provides intensity based data (closer to a value/$ distribution). DLS provides the rapid screening that's needed if you have a bunch of samples to measure. Electron microscopy provides particle size but not particle size distribution.
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