A novel bimetallic MOFs combined with gold nanoflakes in electrochemical sensor for measuring bisphenol A.

In this paper, a novel bimetallic Fe-Cu metal-organic framework combined with 1,3,5-benzenetricarboxylic acid (Fe-Cu-BTC) are synthesized using hydrothermal reaction. The bimetallic Fe-Cu-BTC with high BET (1504 cm3 g-1) and high Langmuir surface area (1831 cm3 g-1) is composited by gold nanoparticles to improve the conductivity and to develop their synergistic effect. A novel bisphenol A (BPA) sensor was prepared by dropcasting Fe-Cu-BTC on glassy carbon electrodes (GCE) followed by AuNPs electrodeposition. The Fe-Cu-BTC framework were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy studies (TEM), FT-IR, BET measurements and EDX spectra. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were carried out for surveying the electrochemical properties of the sensors and for the quantification of BPA. Two linear ranges of BPA concentrations 0.1-1.0 µM and 1.0-18 µM with 18 nM limit of detection were obtained. The developed sensor was used to measure the concentration of BPA in samples extracted from rain coat with the recovery ranging from 85.70 to 103.23%.

Determination of Chromium in Natural Water by Adsorptive Stripping Voltammetry Using In Situ Bismuth Film Electrode.

Development of adsorptive stripping voltammetry (AdSV) combined with in situ prepared bismuth film electrode (in situ BiFE) on glassy carbon disk surface using diethylenetriamine pentaacetic acid (DTPA) as a complexing agent and NO3 - as a catalyst to determine the trace amount of chromium (VI) is demonstrated. According to this method, in the preconcentration step at E dep = -800 mV, the bismuth film is coated on the surface of glassy carbon electrodes simultaneously with the adsorption of complexes Cr(III)-DTPA. In addition to the influencing factors, the stripping voltammetry performance factors such as deposition potential, deposition time, equilibration time, cleaning potential, cleaning time, and technical parameters of differential pulse and square wave voltammetries have been investigated, and the influence of Cr(III), Co(II), Ni(II), Ca(II), Fe(III), SO4 2-, Cl-, and Triton X has also been investigated. This method gained good repeatability with RSD <4% (n = 9) for the differential pulse adsorptive stripping voltammetry (DP-AdSV) and RSD < 3% (n = 7) for the square wave adsorptive stripping voltammetry (SqW-AdSV), and low limit of detection: LOD = 12.10-9 M ≈ 0.6 ppb (at a deposition potential (E dep) of -800 mV and the deposition time (t dep) of 50 s) and LOD = 2.10-9 M ≈ 0.1 ppb (at E dep = -800 mV and t dep = 160 s) for the DP-AdSV and SqW-AdSV, respectively. This method has been successfully applied to analyze chromium in natural water.

An Electrochemical Sensor Based on Gold Nanodendrite/Surfactant Modified Electrode for Bisphenol A Detection.

In the present work, we reported the simple way to fabricate an electrochemical sensing platform to detect Bisphenol A (BPA) using galvanostatic deposition of Au on a glassy carbon electrode covered by cetyltrimethylammonium bromide (CTAB). This material (CTAB) enhances the sensitivity of electrochemical sensors with respect to the detection of BPA. The electrochemical response of the modified GCE to BPA was investigated by cyclic voltammetry and differential pulse voltammetry. The results displayed a low detection limit (22 nm) and a linear range from 0.025 to 10 µm along side with high reproducibility (RSD = 4.9% for seven independent sensors). Importantly, the prepared sensors were selective enough against interferences with other pollutants in the same electrochemical window. Notably, the presented sensors have already proven their ability in detecting BPA in real plastic water drinking bottle samples with high accuracy (recovery range = 96.60%-102.82%) and it is in good agreement with fluorescence measurements.