Figure 4.

DTG ejects specific metal cations (M²⁺) from 4-(2-Pyridylazo)resorcinol (PAR). DTG removes Zn from PAR:Zn. (A) The effect of increasing DTG concentration on the PAR:Zn complex (495 nm). As the concentration of DTG increases the 495 nm peak decreases accompanied by an increased peak at 410 nm representing unbound PAR. (B) The metal chelator TPEN requires a lower concentration to remove the same amount of metal. (C) DTG removes Cu from PAR:Cu. The effect of increasing DTG concentration on the PAR:Cu complex (513 nm). Interestingly, DTG was able to remove Cu from PAR at lower concentrations than when removing Zn. (D) When this is compared to the efficacy of the metal chelator TPEN there is little difference between the two.