Semiconducting-polymer-dot based fluorescent probe for turn-on sensing of phytic acid

In this work, the synthesis of carboxyl functionalized semiconducting polymer dots (PFBT-COOH Pdots) is achieved by a co-precipitation method. The PFBT-COOH Pdots show extraordinary fluorescence brightness and excellent photostability, and the fluorescence of PFBT-COOH Pdots is selectively quenched by ferric ions. Upon addition of phytic acid (PA) to the Pdots/Fe(III) system, PA is able to selectively and preferentially bind with the ferric ions, thus leading to fluorescence recovery of the PFBT-COOH Pdots. Therefore, a simple, selective and sensitive fluorescence probe for PA detection is designed based on the fluorescence quenching-recover process. This probe exhibits a good linear relationship (R = 0.9988) with a linear range from 2.5 μmol L−1 to 450 μmol L−1 and a limit of detection of 0.63 μmol L−1. The probe also shows good selectivity for PA and a good recovery ratio, and it is applied to the determination of PA in a corn grains sample with satisfactory results.