Self-assembled centimetre-sized rods obtained in the oxidation of o -phenylenediamine and aniline

Electrochemical Sensor Based on a Composite of Reduced Graphene Oxide and Molecularly Imprinted Copolymer of Polyaniline-Poly(o-phenylenediamine) for Ciprofloxacin Determination: Fabrication, Characterization, and Performance Evaluation

Contamination of antibiotics in water is a major cause of antibiotic resistance (ABR) in pathogens that endangers human health and food security worldwide. Ciprofloxacin (CIP) is a synthetic fluoroquinolone (FQ) antibiotic and is reportedly present in surface water at a concentration exceeding the ecotoxicological predicted no-effect concentration in some areas. This study fabricated a CIP sensor using an electropolymerized molecularly imprinted polymer (MIP) of polyaniline (PANI) and poly(o-phenylenediamine) (o-PDA) with CIP recognition sites. The MIP was coated on a reduced graphene oxide (rGO)-modified glassy carbon electrode (rGO/GCE) and operated under a differential pulse voltammetry (DPV) mode for CIP detection. The sensor exhibited an excellent response from 1.0 × 10^-9 to 5.0 × 10^-7 mol L^-1 CIP, showing a sensor detection limit and sensitivity of 5.28 × 10^-11 mol L^-1 and 5.78 μA mol^-1 L, respectively. The sensor's sensitivity for CIP was 1.5 times higher than that of the other tested antibiotics, including enrofloxacin (ENR), ofloxacin (OFX), sulfamethoxazole (SMZ), and piperacillin sodium salt (PIP). The reproducibility and reusability of the sensor devices were also studied.

Phenazine-based colorimetric and fluorescent sensor for the selective detection of cyanides based on supramolecular self-assembly in aqueous solution

Taking advantages of both the well-known phenazine structure and the mechanism of the supramolecular self-assembly and deprotonation process, the fluorescent and colorimetric sensor (ZL) was designed and synthesized, behaving as a circulation utilization (above 10 times) receptor for selective detection of cyanide anion (CN^-) in aqueous media. Upon the addition of CN^-, the sensor displayed obvious color changes from yellow to jacinth by naked eyes and the fluorescence immediately quenched (<10s). With respect to other common anions, the sensor possessed high selectivity and sensitivity (0.05μM) for cyanide anions. In addition, the test strips of ZL were fabricated, which could serve as practical colorimetric and fluorescent sensor for "in-the-field" measurements.

Mercaptooxazole–phenazine based blue fluorescent sensor for the ultra-sensitive detection of mercury(ii) ions in aqueous solution

Herein, a fluorescent sensor based on the mechanism of the deprotonation process was designed and synthesized, which could detect Hg²⁺ in aqueous solution with remarkable fluorescence color changed (from yellow to light blue).