We have demonstrated here the dissociation behavior of carboxylic groups at the open end of Single\|Walled Carbon Nanotubes(SWNTs) by tip chemistry. SWNTs were cut into short pipes by acid oxidation and thus carboxylic groups were produced at the end of the tubes. The SWNTs can be immobilized onto AFM tips by surface condensation between amino\|terminated self\|assembled monolayers(SAMs) on AFM tips and carboxylic groups at the end of SWNTs. The p\%K\%\-\{1/2\} value of the SWNTs was then obtained from the force titration measurements of the SWNTs tips \%vs\%. hydroxyl\|terminated SAMs. The results showed a different force titration behaviour and variable p\%K\%\-\{1/2\} values among different SWNTs tips, indicating the variations in the chemistry from tube to tube.
