Fig. 5From: Synthesis of a gadolinium based-macrocyclic MRI contrast agent for effective cancer diagnosisa Chemical structure of xylenol orange with or without metal ion. b Xylenol orange solution in the presence of Gd3+ ion at various concentrations. c Formula for free ion determination. d Xylenol orange solution in the presence of Gd-DOTA-LAEBack to article page