A reversible, colorimetric, pH-responsive indole-based hydrogel and its application in urea detection

Abstract

A new type of pH-responsive indole-based (4-HINF) hydrogel, fabricated by a sol-gel method, was utilized as a platform for colorimetric detection of urea in aqueous solution. The colorimetric sensor was established by virtue of the synergistic effect of cation-π interaction and hydrogen bonding with good regenerative ability. The results exhibited linear response in the range of 0-10 mM with a limit of detection of 10 μM. The prepared 4-HINF hydrogel possessed high selectivity to pH change under complicated environments ensuring further applications in environmental and bio-systems.