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Krister Sundelin

How to convert particles/mL to microgram/mL?

Christopher Imoe  Follow

Yes Kåre surely it depends on their average size. The calculation formula is:
Microgram/ml =2 x 10^11 (particles/ml) * gold density (gm/cm3) * (1/6) (22/7) * (average diameter of particles nm)3  *10^-21 (cm3/nm3) * 10^6 (ugm/gm)
If you take the gold nanoparticles true density: 19.32 g/cm3
Microgram/ml = 20.24^ -4 *(average diameter of particles in nanometer)3
Best regards

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Andy White  Follow

Dear Alan F Rawle ,
you are right:
a) Pi is not a ratio, and
b) 355/113 is closer to Pi than 22/7.

But, nearly everywhere there is a 'but'.
The term '22/7' is well known to me as a simple ratio, which is very close to Pi.
I remember, I have learned that '22/7' as a numerical substitute*) for Pi in a very early course of theoretical physics (last millenium).

One might also use your '355/113', but dividing by 7 is much easier done by head (mental arithmetic) or by pencil, at least for me, than by 113. You know, we had times without any electronic calculator. Incredible nowadays...


*) According to the 'Background' section of

https://en.wikipedia.org/wiki/Proof_that_22/7_exceeds_%CF%80

such a substitute by a ratio is called 'Diophantine approximation'
(I must admit, that I have never heard that term up to now)

https://en.wikipedia.org/wiki/Diophantine_approximation

Best regards
G.M.



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Dipim Gautam  Follow

Gerhard Martens
Yes, I think that all scientists will know that 22/7 is an approximation for pi. I was being a little facetious in suggesting 355/113 (I could have used the even better 52163/16604). I collect old text books (among other things) and a couple of the more interesting ones are:
  • The 'proof' that pi is 3 1/6 or 19/6 (The Measure of the Circle Perfected in January 1845 John Davis Providence 1854). There's no way that Mr Davis is convinced that he is wrong in the 156 pages of the book. Laborious calculations. Sad... I attach a Google Books download
  • Squaring the circle. Numerous examples
Yes, many times approximations are useful (we still teach Dalton's Atomic Theory in schools - all atoms are indivisible - even though it's patently untrue. It has uses.). Reminds me of Rothchild's Law: 'For every phenomenon, however complex, someone will eventually come up with a simple and elegant theory. This theory will be wrong'. Maybe in your field of XRD then the Scherrer equation for crystallite size by line broadening could be an example - sure, small size increases the broadening but there's also strain and instrumental broadening to consider. We can then work with Williamson-Hall or Rietveld...

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Charles Farquhar  Follow
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David  Follow

Thanks Dr Mohammed just a last question the numbers 10E-21 y 10E6 in the equation what that it's mean?. Thanks again.

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Bill Cameron  Follow

Mohammed Hussein j. H. Al'Atia
You state 'Where π is the constant ratio = 22/7'.
Pi is not a ratio - it is a completely irrational number that cannot be expressed as a fraction. If so, why not use 355/113 which is closer?

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Blair Blakely  Follow

Dear Mayra Beltran
Thank you for your feedback
10^-21 is the conversion factors from cm3 to nm3
10^6 is the conversion factors from ugm to gm
Best regards

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Andrew White  Follow

Yes Kåre surely it depends on their average size. The calculation formula is:
Microgram/ml =2 x 10^11 (particles/ml) * gold density (gm/cm3) * (1/6) (22/7) * (average diameter of particles nm)3  *10^-21 (cm3/nm3) * 10^6 (ugm/gm)
If you take the gold nanoparticles true density: 19.32 g/cm3
Microgram/ml = 20.24^ -4 *(average diameter of particles in nanometer)3.

Is there any formula like the above for calculating microplastic particle conversion from particles/mL to microgram/mL?

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Barbara Mckeon  Follow

Yes Monique
Microgram/ml = 20.24^ -4 *(average diameter of particles in nanometer)3
Microgram/ml = 20.24^ -4 *(30nm)3
                         = 54.64 
Best regards

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Arega Tayu  Follow

Dear Dr Muhammad,

I am working with 3 sizes of gold nano particles 5nm, 20nm and 40nm with 4.92E+13 - 6.01E+13, 5.89E+11-7.19E+11 and 6.44E+10-7.87E+10 concentrations particles/ml respectively. Could you please help me to covert these concentrations to ug/ml?

Best regards
Mehwish

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Bill Richards  Follow

may I know the reference or Paper that uses the formula (Concentration Particle / ml into mg/ml) like your discussion in this link (https://www.researchgate.net/post/How-to-convert-particles-mL-to- microgram-mL) Prof Mohammed Hussein j. H. Al'Atia and Monique Engelbrecht

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Darla  Follow

Ridhwan Haliq You need to open a separate question (as you have done) rather than confusing this thread. It is likely that you'll not get a reply here as people will not look at old questions generally.

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