17th refers to the experimental parameter code
Material is mesoporous silica nanoparticles (MSN-NH2).
Use deionized water as dispersant and ultrasonic vibration.
The theoretical concentration is 9.6*10^(−5)g/ml.
The instrument used is zetasizer nano zs, the instrument is a bit old.
Bo Lin There is so much to comment on here. First, run a standard material (e.g. 60, 100, or 220 nm latex) to confirm instrument performance. Pay for a service engineer to visit your site and also an application specialist for training on the instrument. The measurement that has been taken is basically noise and should be discarded. The correlogram should be a nice exponential decay - it isn't... The quality report (in red) tells you all of this and more. The concentration you have is way too low for measurement - the attenuator (position 11) and count also tell you this. Increase the concentration by a factor of 100 minimum, probably 1000 to 10000 times. You claim to be measuring in DI water and yet you have a temperature set of 113.3 C. What's going on here? Why haven't the automatic settings been used? Have you filtered the sample free from garbage? You may have large contamination present obscuring the scattering you wish to see? What is the expected size of your silica?
Repeat the experiment with a known standard and contact your local supplier.
Hello, thank you very much for your reply, and sorry for the late response.
The correction was done a few weeks before I started using it.
Previous experiments showed that increasing the concentration would cause the counting rate to be too high and the agglomeration of nanoparticles to be more obvious, which was different from the SEM.
I'm pretty sure the temperature is set at 25°C. I'm not sure why it always says 113°C when measuring.
My expected size falls between 70-250nm, because the SEM results fall roughly within this range.
I would like to ask another question. If the quality report shows good, does it mean that the result can be trusted and adopted? Thanks again for your answer.
Bo Lin Thank you for your response.
Material in the 70 - 250 nm range should be ideal for DLS - plenty of scattering. You need to increase the concentration until the attenuator is approximately in the ideal position of 7. Generally if the Quality Report shows 'Good' then there are no obvious measurement issues highlighted. Verification of a system is always via a certified standard.
Again, it's clear you need training on the system. You have manual measurements and have set the device temperature (manually) to 113 C - which it's not possible to achieve with water...
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