CBA has a plate reader - can return flourescent concentration (not individual particle #) but requries optimization \
or confocal microscope - collect particels in iminger with water solution, let colloidal solution evaporate leaving particles on stage and record particle desnity in an image
### microgram mass comparison of gold particles
test measurement with 100nm gold particles \
from bbi solutions dataseet for 100nm gold particles - mass of 1L of gold is 5.66E-05 g, too small for the analytical balance in BL1 \
also, I tried measuring evaporated solution on a few microscope slides and the slides are not uniform enough to do comparative measurements. \
but can see the particles in the Olympus microscope

### Resources
### Resources
[^DIYmask]:University of Cambridge [DIY mask efficacy testing](https://www.researchgate.net/publication/258525804_Testing_the_Efficacy_of_Homemade_Masks_Would_They_Protect_in_an_Influenza_Pandemic)
[^DIYmask]:University of Cambridge [DIY mask efficacy testing](https://www.researchgate.net/publication/258525804_Testing_the_Efficacy_of_Homemade_Masks_Would_They_Protect_in_an_Influenza_Pandemic)
[^filterPerformance]:AR Wilkes [The bacterial and viral filtration performance of breathing system filters](https://onlinelibrary.wiley.com/doi/full/10.1046/j.1365-2044.2000.01327.x)
[^filterPerformance]:AR Wilkes [The bacterial and viral filtration performance of breathing system filters](https://onlinelibrary.wiley.com/doi/full/10.1046/j.1365-2044.2000.01327.x)