To further investigate the retention mechanism, glucose (0 mM to 125 mM) was added into the mobile phase to create an external cis-diol-competition environment.
The results showed that the retention of 2′-deoxyadenosine remained constant (1.3 ± 0.1 min), whereas the retention of adenosine sharply decreased with the addition of the “competitor”, glucose (from 57.5 to 5.5 min; Table 1).
Such phenomenon strongly pointed to the affinity interaction between TiO2 and cis-diol-containing compounds.