Table 4.

Concentration of ionic silicon measured in the filtrate of nanoparticle suspensions of various sizes (average concentrations ± SD, n = 3)

Silica nanoparticle size [nm]	Average concentration of ionic silicon in the filtrate ± SD (n = 3) [ppb]
Blank (1% nitric acid)	22.0 ± 0.5
20 nm	21.6 ± 0.8
40 nm	22.6 ± 1.2
60 nm	23.5 ± 0.6
80 nm	32.2 ± 0.9
100 nm	22.8 ± 0.7
150 nm	21.1 ± 1.0