I want to count the number of colloidal particles.
The polystyrene bead(Diameter = 1um) is suspended in the DI Water. Is there any method to count the number of particles per volume or else?
Jongbin Won
Welcome to Research Gate and your first question!
Lots of ways. But why is number of particles important from you? How does the number of particles relate to critical quality attributes or product performance indicators?
Some routes: light obscuration, electrical sensing zone, resonant mass measurement (RMM), nanoparticle tracking (NTA) and so on. Google is your friend.
I have a long experience of preparing colloidal MnO2. It shows Tyndall effect and some other unique properties. But why do you need to count particle number?
Sometime, it needs to konw the distribution of the particles diameter, and the number of the particles is not so necessary. But if you want to konw the number of the particle solution, you can use the dynamic light scattering (DLS) technology to measure, or you can use the SEM to count the number of a small area by Image J then you can estimate the number by the small number. Hope it is helpful for you.
Qifeng Mu DLS measures an intensity distribution and does not count particle. Conversion of the intensity distribution to number is ‘deprecated’ in the international standards (ISO22412:2017 & ASTM E2490-09(15)).
Thank you for the answer! I'm trying to capture the particles and analyze the system by numerically. But I couldn't know the concentration(?) of the suspension. I would try the method at the answer!
Jongbin Won I am not sure what you mean and you still haven't answered my question. How do numbers of particles (rather than surface area or mass/volume) affect, or relate to, your key parameters? This should be the reason for doing the experiment.
The concentration can be measured in a number of ways such as particles/mL or particles per μL or moles/L etc. All the methods I indicated above will give a concentration in numbers particles per unit volume. You can also use chemical means (e.g. titration) or gravimetric (e.g. evaporation of solution) for measuring concentration. The last is a good example - one would have a mass of material per volume of liquid. This is a perfectly acceptable method of defining concentration.
Alan F Rawle I'm really sorry. I wanted to answer but it's been so busy.
I am trying to catch the particle in certain area by using dep and want to know the efficiency of the system. I thought if I can calculate the number of entire particle and the particle caught by the dep, I could know the efficiency of the system.
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