Selective Detection of H2O2 Using para-Phenylenediamine Capped Ce~(3+)/Tb~(3+)-Doped NaYF4 Microrods

摘要

In this work, we have shown the use of Ln~(3+)-doped nano- materials for the selective detection of H2O2 upto nM concen- tration. This is achieved by capping the Ce~(3+)/Tb~(3+)-doped NaYF4 microrods using para-phenylenediamine (p-PDA). The microrods show strong green emission upon UV excitation due to strong energy transfer from Ce~(3+) to Tb~(3+) ions. This strong energy transfer is selectively quenched upon addition of H2O2 leading to reduction in the green emission intensity. This se- lective quenching of the green emission is due to oxidation of p-PDA to Bandrowski’s base which has strong absorption band close to 310 nm, which falls in 4f5d emission level of Ce~(3+) ions. The proposed mechanism is also supported by TD-CAM-DFT calculations performed on p-PDA and its oxidized product. The reduction in the emission intensity is found to be very selective which is verified by the addition of other analytes (glucose, glu- tamic acid, uric acid, urea, tryptophan, aspartic acid and some metal ions, Na~+,K~+,SO4 ~(2+), and Mg~(2+)) which normally co-exist with H2O2 in the body. More than 90% of the initial intensity of the Tb~(3+) was recovered upon the addition of a NaBH4 solution. The study clearly implies that the resonance energy transfer (RET) using Ln~(3+)-doped microrods can serve as a tool to se- lectively detect H2O2 upto the nanomolar concentration.