An ion-based chromogenic detecting method for phosphate-containing derivatives in physiological condition

The detection for phosphate-containing and ATP in water is a challenging task. Here, we report a simple and sensitive method for detecting both HPO42− and ATP in aqueous solution. The new ensemble is prepared by mixing ytterbium chloride and pyrocatechol violet in a 2:1 molar ratio in aqueous solution of 10 mM 2-[4-(2-hydroxyethyl)-1-piperazinyl] ethanesulfonic acid (HEPES) buffer at pH 7.0. Upon the addition of YbCl3, the maximum absorption peak gradually shifted from 444 nm (yellow) to 623 nm (blue). With the addition of HPO42− or ATP solution into the system, the ensemble resulted in a change back of color from blue to yellow and caused a variation in UV-vis absorption spectra. The ensemble exhibits excellent selectivity for HPO42− and ATP over other common anions including Cl−, SO42−, CH3COO−, HClO4− and HCO3−.