Suxia Wang,Min Zhou,Yongxi Zhu,Bo Peng,Jia Yang,Yongjun Ma
In this study, a novel poly(L-citrulline)/lanthanide-containing cyano-bridged heterometallic coordination polymer modified glassy carbon electrode, poly(L-Cit)/(Ho(III)-Fe(III)-WO42− CyHMCP/GCE, was constructed as a sensing platform for the electrochemical detection of 3-nitropropionic acid (3-NPA) using the two-step electrosynthesis method. The surface morphology of materials coated on the chemically modified electrode was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Based on the excellent synergistic electrocatalytic performance for electrochemical reduction of 3-NPA, the voltammetric detection of 3-NPA in real sugarcane juice samples was achieved with a facile sample pretreatment process and less matrix interference. Furthermore, by means of water-phase infrared spectra technique, the electrocatalytic reduction pathway of 3-NPA was preliminarily studied. Under the optimized detection conditions, a good linear relationship was obtained between the reduction peak current of 3-NPA and testing concentration in the range of 40.0–4.00 × 103 μM, with a regression equation of Ip (μA) = −3.126 + 0.08804C3-NPA (μM), R2 = 0.9997. The lower detection limit (LOD) of 3-NPA was estimated to be 16.0 μM (S/N = 3). Therefore, the method had been employed to analyze raw sugarcane samples, with the average recovery of 96.8%–104%, and the actual concentration level of free 3-NPA in the raw sugarcane juices was revealed.
Designed and synthesized a series of imidazolium-functionalized Poly (2, 6-dimethyl-1, 4-phenylene oxide) (Im-PPO) containing pendant imidazole groups, which were used to supply functional sites for acid–base interaction with the doping phosphoric acid. The imidazolium-functionalized Poly (2, 6-dimethyl-1, 4-phenylene oxide) membranes obtained by the solution-casting method were doped with phosphoric acid (PA). The PA content, swelling, and tensile strength of the different membranes doped with PA were measured. With the increase of the length of side chains on the imidazole groups, the membrane showed different properties. The proton conductivity at a level of 3.7 × 10−2 S/cm was achieved at 160°C by the MeIm-PPO imidazolium composite membrane.
Nitrophenols, essential chemical feedstocks, are released into the ecosystem during food production. Given their toxicity, persistence and health risks, accurate visual field analyzers for nitrophenols are essential. Herein, we synthesize novel triple-excited carbon dots (TE-CDs) and design an excitation-driven ratiometric detection method to quantitatively determine and distinguish nitrophenols under neutral conditions. Specifically, the excitation intensities of TE-CDs are selectively quenched by the localization of inner filter effect in the presence of nitrophenols. Nitrophenols can be divided into 4-nitrophenol, 3-nitrophenol and 2-nitrophenol with detection limits of 78 nM, 115 nM and 96 nM. In addition, mixed nitrophenols can be further distinguished by means of hierarchical cluster analysis and linear discriminant analysis with high reliability. Furthermore, a smartphone-integrated sensor with a TE-CDs-based film is designed, demonstrating commendable accuracy and precision in actual applications. Consequently, this study presents a robust methodology for in situ monitoring and intelligent sensing of nitrophenols under neutral conditions.
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