Simultaneous detection of iodine and iodide on boron doped diamond electrodes

Individual and simultaneous electrochemical detection of iodide and iodine has been performed via cyclic voltammetry on boron doped diamond (SOD) electrodes in a 1 M NaClO4 (pH 8) solution, representative of typical environmental water conditions. It is feasible to compute accurate calibration curve for both compounds using cyclic voltammetry measurements by determining the peak current intensities as a function of the concentration. A lower detection limit of about 20 mu M was obtained for iodide and 10 mu M for iodine. Based on the comparison between the peak current intensities reported during the oxidation of KI, it is probable that iodide (I-) is first oxidized in a single step to yield iodine (I-2). The latter is further oxidized to obtain IO3-. This technique, however, did not allow for a reasonably accurate detection of iodate (IO3-) on a BDD electrode. (C) 2012 Elsevier B.V. All rights reserved

Cathodic pretreatment improves the resistance of boron-doped diamond electrodes to dopamine fouling

The resistance of cathodically and anodically treated boron-doped diamond electrodes to dopamine fouling was investigated. It was found, using cyclic voltammetry and electrochemical impedance spectroscopy, that the cathodic preparation offers an increased resistance to fouling, in addition to an enhanced electrochemical response

Electronic structures of B-2p and C-2p of boron-doped diamond film by soft X-ray absorption and emission spectroscopy

X-ray absorption (XAS) and emission (XES) spectroscopy near B-K and C-K edges have been performed on metallic (~1at%B, B-diamond) and semiconducting (~0.1at%B and N, BN-diamond) doped-diamond films. Both B-K XAS and XES spectra shows metallic partial density of state (PDOS) with the Fermi energy of 185.3 eV, and there is no apparent boron-concentration dependence in contrast to the different electric property. In C-K XAS spectrum of B-diamond, the impurity state ascribed to boron is clearly observed near the Fermi level. The Fermi energy is found to be almost same with the top of the valence band of non-doped diamond, E_V, 283.9 eV. C-K XAS of BN-diamond shows both the B-induced shallow level and N-induced deep-and-broad levels as the in-gap states, in which the shallow level is in good agreement with the activation energy (E_a=0.37 eV) estimated from the temperature dependence of the conductivity, namely the change in C-2p PDOS of impurity-induced metallization is directly observed. The electric property of this diamond is mainly ascribed to the electronic structure of C-2p near the Fermi level. The observed XES spectra are compared with the DVX-alpha cluster calculation. The DVX-alpha result supports the strong hybridization between B-2p and C-2p observed in XAS and XES spectra, and suggests that the small amount of borons (<1at%) in diamond occupy the substitutional site rather than interstitial site.Comment: submitted to Phys. Rev. B, 5 pages and 5 figure

A rapid and simple electrochemical detection of the free drug concentration in human serum using boron-doped diamond electrodes

Monitoring drug concentration in blood and reflecting this in the dosage are crucial for safe and effective drug treatment. Most drug assays are based on total concentrations of bound and unbound proteins in the serum, although only the unbound concentration causes beneficial and adverse events. Monitoring the unbound concentration alone is expected to provide a means for further optimisation of drug treatment. However, unbound concentration monitoring has not been routinely used for drug treatment due to the long analysis time and the high cost of conventional methods. Here, we have developed a rapid electrochemical method to determine the unbound concentration in ultrafiltered human serum using boron-doped diamond (BDD) electrodes. When the anticancer drug doxorubicin was used as the test drug, the catalytic doxorubicin-mediated reduction of dissolved oxygen provided a sensitive electrochemical signal, with a detection limit of 0.14 nM. In contrast, the sensitivity of glassy carbon (GC) was inferior under the same conditions due to interference from the dissolved oxygen reduction current. The signal background ratio (S/B) of BDD and GC was 11.5 (10 nM doxorubicin) and 1.1 (50 nM), respectively. The results show that a fast measurement time within ten seconds is possible in the clinical concentration range. Additionally, in the ultrafiltered human serum, the obtained values of unbound doxorubicin concentration showed good agreement with those quantified by conventional liquid chromatography-mass spectrometry. This approach has the potential for application in clinical settings where rapid and simple analysis methods would be beneficial.Reproduced from Analyst., 2022, 147, 4442-4449 with permission from the Royal Society of Chemistry.https://doi.org/10.1039/d2an01037

An iron(II) incomplete spin-crossover compound: pressure effects and Mossbauer spectroscopy study

A one-dimensional iron(II) spin-crossover compound [Fe(3py-im)(2)(NCS)(2)]center dot 7H(2)O (1) (3py-im = 2,4,5-tris(4-pyridly)-imidazole) has been solvothermally synthesized and structurally characterized. Compound 1 crystallizes in the monoclinic space group P2/c with a = 11.9078(2), b = 9.9474(1), c = 17.7290(3) and beta = 102.361(2)degrees at 105 K. Studies on the variable-temperature magnetic susceptibilities and Mossbauer spectra suggest that compound 1 undergoes incomplete spin transition behaviour. Pressure effects on the transition behaviour have also been investigated, the thermal-induced spin transition becomes more gradual and the critical temperature shifts towards slightly higher temperature range when external pressure increases. However, the spin transition can not be completed by applying external pressure even as high as 0.79 GPa.NNSF of China [20721001, 20971106, 90922012]; MOE [NCET-08-0470]; NSF of Fujian Province for Distinguished Young Scientists [2009J06006]; National Basic Research Programof China [2007CB815301

The Dependence of Boron Concentration in Diamond Electrode for Ciprofloxacin Electrochemical Sensor Application

This study investigates the effects of boron concentration on boron-doped diamond (BDD) electrodes for electrochemical sensors of ciprofloxacin. The effects of boron concentration, scan rate, and pH of BDD electrodes with boron concentrations of 0.1, 0.5, and 1% were examined to determine the optimal conditions. Furthermore, square wave voltammetry (SWV) in phosphate buffer pH 7 was used to analyze the electrochemical behavior of ciprofloxacin. The results revealed a linear calibration curve in the concentration range of 30–100 μM with a recovery of 85–110%. Meanwhile, BDD electrode with the highest boron concentration in this experiment (1%) showed a very low limit of detection of 0.17 μM, meaning that 1% BDD gave a highly sensitive and significant measurement result for the electrochemical sensor of ciprofloxacin. With the results given, this study provides new insights for controlling boron concentrations in diamond electrodes for the electrochemical sensors of quinolone antibiotics

Pressure effects and Mossbauer spectroscopic studies on a 3D mixed-valence iron spin-crossover complex with NiAs topology

A three-dimensional mixed-valence iron complex with NiAs-type topology, [((Fe3O)-O-III)Fe-II(TA)(6)(H2O)(3)]center dot(CIO4)(2)(NO3)(EtOH)(H2O)(2)(1, HTA = tetrazole-1H-acetic acid), shows spin-crossover behavior that was characterized via variable-temperature crystal structures, Mossbauer spectra and magnetic susceptibilities, the pressure effects on the transition behavior were also studied