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. Author manuscript; available in PMC: 2010 Jan 7.
Published in final edited form as: J Toxicol Environ Health A. 2009;72(2):60–73. doi: 10.1080/15287390802476991

Table 1.

Characterization of surface functional groups present on MWCNT using a Knudsen flow reactor.

Gas [gas-phase probe molecules] N(CH3)3 [acidic sites] HCl [basic sites] CF3COOH [basic sites] NH2OH [carbonyl functions] O3 [oxidizable sites] NO2 [oxidizable sites]
no/mga 3.0.1015 8.1.1016 2.4.1016 2.4.1017 3.9.1018 1.2.1016
no/cm2b 1.4.1012 3.7.1013 1.1.1013 1.1.1014 1.8.1015 5.3.1012
MLc 0.28% 7.4% 2.2% 22% 360% 1.1%

Results are expressed as indicated in footnotes a, b and c and using a BET surface of 219.2 m2/g.

a

number of probe molecules taken up per mg of deposited nanoparticles

b

number of probe molecules taken up per square cm of MWCNT (no/cm2)

c

number or fraction of formal monolayer (ML) of reacted probe gas using an average of 5x1014 molecules cm-2 as one formal ML.