A novel method for the analysis of calf thymus DNA based on CdTe quantum dots-Ru(bpy)32+ photoinduced electron transfer system

A method has been developed for the rapid determination of calf thymus (ct) DNA that is based on the photoinduced electron transfer (PET) that occurs between CdTe quantum dots and the ruthenium(II)tris-bipyridyl complex. The latter quenches the photoluminescence (PL) of the quantum dots through PET. The Stern-Volmer quenching constant is 2,500 L mol−1. The intensity of the PL the system is recovered in the presence of ct DNA, and relative recovered PL intensity is linearly proportional to the concentration of ct-DNA. The dynamic range is from 17 µM to 1.5 mM of DNA, and the detection limit (at S/N = 3) is 5.7 µM. The relative standard deviation (at 0.5 mM of ct-DNA) is 4.1% (n = 11). A possible reaction mechanism is discussed.