Vein-Like Ni-BTC@Ni3S4 with Sulfur Vacancy and Ni3+ Fabricated In Situ Etching Vulcanization Strategy for an Electrochemical Sensor of Dopamine.

In this study, a novel Ni-BTC@Ni3S4 composite was fabricated by solvothermal reaction using an in situ etching vulcanization strategy and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and Brunauer-Emmett-Teller (BET) analyses. The existence of a sulfur vacancy and Ni3+ in the as-prepared vein-like Ni-BTC@Ni3S4 greatly promoted the electrochemical sensing activity of the materials. Herein, a simple electrochemical sensor (Ni-BTC@Ni3S4/CPE) has been fabricated and used for the detection of dopamine (DA). The current signal of the Ni-BTC@Ni3S4/CPE-modified electrode was linear with the concentration of DA in the range of 0.05-750 µM (R2 = 0.9995) with a sensitivity of 560.27 µA·mM-1·cm-2 and a detection limit of 0.016 µM. At the same time, the sensor has good stability and anti-interference ability. This study could provide a new idea and strategy for the structural regulation of composite electrode-modified materials and sensitive sensing detection of small biological molecules.

Controlled growth of calcium oxalate crystal in bicontinuous microemulsions containing amino acids.

The growth of calcium oxalate (CaC(2)O(4)) crystal in water channels of three kinds of bicontinuous microemulsions, consisted of P-octyl polyethylene glycol phenylether (OP)/n-amyl alcohol/cyclohexane/water and above microemulsions containing tryptophan (Trp) or aspartic acid (Asp) has been studied. The products were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The results indicated that both surfactant and amino acids all could prompt the growth of calcium oxalate monohydrate (COM) crystal, but the crystal morphology varied with the different microemulsions, pH values of the aqueous solution in channels and concentrations of the reactants. Various crystal morphologies such as butterfly-like, hollow and spiny spherical could be observed easily. A model of molecular identification--organized assembly--pervasion-combination balance was proposed to explain the formation mechanism of CaC(2)O(4) crystals in the microemulsions containing Asp.