Surface modification of titanium dioxide (TiO2) with enediol like dopamine improves its optoelectronic properties due to chelation of Ti atom by electron donating bidentate ligand. Introduction of N in TiO2 is expected to weaken the interaction between Ti atoms and bidentate ligand because of extra active acceptor sites. Hence, the chemistry of N doped TiO2 and dopamine is likely to display contradictory behavior in comparison to TiO2-dopamine. In this study, amorphous TiO2-xNx nanosheet were synthesized incorporating diethyl triamine (DETA) and acetonitrile (ACN) which plays significant role in obtaining desired morphology. Furthermore, the chemistry of interaction between TiO2-xNx and dopamine was explored, wherein dopamine self-polymerizes on the surface of nanosheets forming TiO2-xNx – Polydopamine (PD). Comparative study of TiO2-xNx–PD and TiO2-PD were investigated in presence of similar enediol ligand such as ascorbic acid (AA) along with weak and strong acid. It was observed that only in presence of AA, TiO2-xNx–PD bond gets weaken from the fluorescence recovery of PD. This behavior of AA was tested with a detection range of 10–100 nM and limit of detection of 2 pM in biological fluid. Our results could be helpful for tuning the optoelectronic properties of TiO2 based hybrid composites for future applications.