Hi,
Thank you in advance for your replies.
I am looking for the conversion of microplastic and nanoplastic particles whose concentrations in experiments are measured in particles/mL or particles/L to microgram/L.
There is a conversion formula which is used in case of Au and Ag particles, but I assume the same cannot be applied here since they are microplastics.
All answers are welcome to solve this conversion.
Thank you
Suggests calculating the volume of the particles. One can use simple geometric shapes, such as sphere, cylinder and so on. The dimensions are measured with a microscope. The density is approximately = 1. There are methods for counting plankton, which can be used on microplastics.
Hello Vrinda,
To my knowledge, it is hard to link the number of MPs with their weight! The differences in size, types, and composition will change the particle density.
The most reliable way is to measure with a precision scale! Maybe you can gather the MPs having the same type, size, and composition to measure them in a pool then divide by the number.
Waiting for a better answer, wishing you the best of luck!
M.B.
It will be difficult for a different reason:
"Microplastics like polypropylene are lighter than seawater and will float and disperse widely across waterways. Microplastics like acrylic are denser than seawater and will accumulate in the deepest parts of the ocean"
https://www.greenfacts.org/en/marine-litter/l-2/3-micro-plastics.htm#:~:text=Basically%20some%20plastics%20float%20and,eventually%20sink%20to%20the%20seafloor.
Here is a list of plastic densitys:
https://omnexus.specialchem.com/polymer-properties/properties/density
1 mL = 1000 µL 1 µL = 0.001 mL
Example: convert 15 mL to µL: 15 mL = 15 × 1000 µL = 15000 µL
Vrinda Sukumaran
Hey! I can talk a little bit about my particular experience with this.
You need to define a specific conversion equation for each type of MP you are using. It will depend on the size range, shape and polymer type. And if you have to have a regular distribution with respect to size. It's much easier when using an MP with regular edges.
One way you can do this with irregular MPs would be to weigh a specific amount of particles (as little as possible; eg 20 μg) and count them under a microscope (you should do this in triplicate or with more replicates). But it will only work if you have a regular distribution.
You can also use a wet method by making a suspension (in water or tween; depending on the polymer) with a known concentration: place 1 μL of this suspension on a slide and count under a microscope (I usually make 10 replicates). Then you do the conversion between the amount of particles per μL/mL/L. (I can say that this method works fine for PS spheres, but not for PE fragments)
Oh, and if you have cell counting software, you can adapt it for this use!
Good luck =)
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