Fig. 21. Photographs of TLC plates after immersion in an RQBT–MeOH solution (i) and after immersion in an RQBT–Cd²⁺ methanol solution (ii) taken in ambient light (a) and under hand-held UV light (b). Excitation wavelength of the UV light is 365 nm. Adapted from ref. 109 with permission from American Chemical Society, copyright 2015.