Highly sensitive “turn-on” fluorescent chemical sensor for trace analysis of Cr3 + using electro-synthesized poly(N-(9-fluorenylmethoxycarbonyl)-l-histidine)

Trivalent chromium (Cr 3   + ) can cause severely environment pollution, declining quality of edible agro-products in plants and animals, and human diseases. Poly( N -(9-fluorenylmethoxycarbonyl)- l -histidine) (PFLH) synthesized by the direct electro-polymerization of its corresponding commercially available monomer in both boron trifluoride diethyl etherate and dichloromethane mixed system. The “turn-on” type fluorescent sensor based on PFLH displayed high sensitivity and selectivity for Cr 3   + detecting. The structure of PFLH was rationally proved by 1 H NMR spectra, FT-IR spectra, quantum chemical calculations , and its optical properties were characterized. The electro-synthesized PFLH exhibited a “turn-on” fluorescent response towards Cr 3   + , which was employed as a sensing platform for the “turn-on” fluorescent analysis of Cr 3   + in a wide linear range from 5.1   nM to 25   μM with a low limit of detection as low as 1.7   nM. The possible mechanism of fluorescent “turn-on” sensor based on PFLH for Cr 3   + was proposed. The sensor displayed high sensitivity, good selectivity, satisfactory practicability, suggesting that PFLH has potential fluorescent application for “turn-on” sensing Cr 3   + in agricultural environments and edible agro-products of plants and animals.