A naphthol‐based fluorescence turn‐on sensor for detecting Ga(III) and its application to test strips

A new naphthol‐based chemosensor NPN ((E)‐2‐(((2‐hydroxynaphthalen‐1‐ylmethylene)amino)isoindoline‐1,3‐dione) was synthesized. NPN could sense Ga3+ by a fluorescence “turn‐on” method from colorless to blue. Detection limit for Ga3+ by NPN was determined to be 0.26 μM. The sensing mode of NPN and Ga3+ turned out to be a 1:1. NPN could also be successfully applied to visible fluorescent test strips. The sensing process of Ga3+ by NPN was illustrated through 1H NMR titration, Job plot, ESI‐MS, and DFT calculations.