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Continuous and real-time measurement of local concentrations of systemically administered drugs in vivo must be crucial for pharmacological studies. Nevertheless, conventional methods require considerable samples quantity and have poor sampling rates. Additionally, they cannot determine how drug kinetics correlates with target function over time. Here, we describe a system with two different sensors. One is a needle-type microsensor composed of boron-doped diamond with a tip of ~40 μm in diameter, and the other is a glass microelectrode. We first tested bumetanide. This diuretic can induce deafness. In the guinea-pig cochlea injected intravenously with bumetanide, the changes of the drug concentration and the extracellular potential underlying hearing were simultaneously measured in real time. We further examined an antiepileptic drug lamotrigine in the rat brain, and tracked its kinetics and at the same time the local field potentials representing neuronal activity. The action of the anticancer reagent doxorubicin was also monitored in the cochlea. This microsensing system may be applied to analyze pharmacokinetics and pharmacodynamics of various drugs at local sites in vivo, and contribute to promoting the pharmacological researches.

A novel star-shaped high-spin Fe(III) tetranuclear cluster was unexpectedly obtained by the reaction of an [FeIII(phsal)2]− anion with an Fe(II) coordination cation (H2phsal: N-(2-hydroxyphenyl)sal...

The catalytic, electrocatalytic, or photocatalytic conversion of CO2 into useful chemicals in high yield for industrial applications has so far proven difficult. Herein, we present our work on the electrochemical reduction of CO2 in seawater using a boron-doped diamond (BDD) electrode under ambient conditions to produce formaldehyde. This method overcomes the usual limitation of the low yield of higher-order products, and also reduces the generation of H2 . In comparison with other electrode materials, BDD electrodes have a wide potential window and high electrochemical stability, and, moreover, exhibit very high Faradaic efficiency (74%) for the production of formaldehyde, using either methanol, aqueous NaCl, or seawater as the electrolyte. The high Faradaic efficiency is attributed to the sp(3)-bonded carbon of the BDD. Our results have wide ranging implications for the efficient and cost-effective conversion of CO2.

An electrolyte-free system for electrochemical ozone generation was developed using boron-doped diamond (BDD) electrodes as the anode and cathodes in combination with Nafion® N117/H+ as the separating membrane. Trials using BDD with various B/C ratios suggested that heavily boron-doped BDD with sp2 impurities yielded high concentration of ozone. Further experiments by replacement of the feedstock solutions with 0.85 M Na2SO4 or 0.85 M NaCl resulted in no significant difference, suggesting that the use of pure water as the feedstock is the most appropriate method for ozone production. A high efficiency could be achieved by applying water as a feedstock for the anode and the cathode chambers. In addition, comparison with Pt electrodes confirmed that the excellent structural stability of BDD was the main factor contributing to this success.

The maximum current flowed with zero resistance, referred to the critical current density, is desired to be sufficiently large in order to apply superconducting wire rods and electromagnets to various devices. Although the critical current density can be enhanced by introduction of non-superconducting impurities, the transition temperature would become diminished in such a case. Here, we report modulation of a critical current density in heavily boron-doped diamonds (BDDs) by changing the surface-termination without introducing any impurity. The surface of a BDD was changed between hydrogen- and oxygen-termination. As a result, the critical current density could be modulated in a reversible manner between the hydrogen- and oxygen-terminated diamonds with maintenance of the superconducting transition temperature. This is because the volume fractions of the superconducting phases were modulated by surface modification.

The influence of support electrolyte on the electrochemical degradation of formic acid was studied on boron-doped diamond (BDD) electrodes. Experimental data are compared with a theoretical model, ...

The electrochemical detection of lipophilic antioxidants, α-tocopherol (vitamin E, VE) and ubiquinone (coenzyme Q10, CoQ10), in methanol and in methanol/hexane mixture solutions, respectively, at boron-doped diamond (BDD) electrodes was investigated by cyclic voltammetry (CV) and flow-injection electrochemical measurements. CV measurements revealed that the overpotential for electrochemical reaction of VE and CoQ10 was larger at an oxidized BDD electrode surface than at that of a hydrogenated BDD (H-BDD) electrode. The slope of the CV calibration curve used to determine the VE and CoQ10 concentrations was larger at a glassy carbon (GC) electrode than at the H-BDD electrode; however, the signal-to-background ratio was larger at the H-BDD electrode than at the GC electrode, due to the low background feature of the H-BDD electrode. The limit of detection (LOD), defined by a signal-to-noise ratio of three for flow-injection electrochemical detection, was much smaller at the H-BDD electrode (VE: 41 nM and CoQ10: 17 nM) than at the GC electrode (VE: 263 nM and CoQ10: 71 nM). These results confirm that the H-BDD electrode is reliable for the electrochemical detection of lipophilic antioxidants, especially at low concentrations.

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.

The electrochemical detection of oxytocin using boron-doped diamond (BDD) electrodes was studied. Cyclic voltammetry of oxytocin in a phosphate buffer solution exhibits an oxidation peak at +0.7 V (vs. Ag/AgCl), which is attributable to oxidation of the phenolic group in the tyrosyl moiety. Furthermore, the linearity of the current peaks obtained in flow injection analysis (FIA) using BDD microelectrodes over the oxytocin concentration range from 0.1 to 10.0 μM with a detection limit of 50 nM (S/N = 3) was high (R2 = 0.995). Although the voltammograms of oxytocin and vasopressin observed with an as-deposited BDD electrode, as well as with a cathodically-reduced BDD electrode, were similar, a clear distinction was observed with anodically-oxidized BDD electrodes due to the attractive interaction between vasopressin and the oxidized BDD surface. By means of this distinction, selective measurements using chronoamperometry combined with flow injection analysis at an optimized potential were demonstrated, indicating the possibility of making selective in situ or in vivo measurements of oxytocin.

Boron-doped diamond electrodes have attracted increasing interest from researchers due to their outstanding properties for electroanalysis and other electrochemical applications. Material quality and availability have come a long way since the initial reports on the basic electrochemical properties back in the late 1980s and early 1990s. In this review, we highlight how diamond electrochemistry has diversified and matured in recent years in terms of the understanding of structure-property relationships and the development of new applications of materials in electroanalytical chemistry. © Materials Research Society 2014.

Electrolytic corrosion of boron-doped diamond (BDD) electrodes after applying a high positive potential to decompose organic compounds in aqueous solution was studied. Scanning electron microscopy images, Raman spectra, and glow discharge optical emission spectroscopy revealed that relatively highly boron-doped domains were primarily corroded and relatively low boron-doped domains remained after electrolysis. The corrosion due to electrolysis was observed especially in aqueous solutions of acetic acid or propionic acid, while it was not observed in other organic compounds such as formic acid, glucose, and methanol. Electron spin resonance measurements after electrolysis in the acetic acid solution revealed the generation of methyl radicals on the BDD electrodes. Here, the possible mechanisms for the corrosion are discussed. Dangling bonds may be formed due to abstraction of OH groups from C–OH functional groups by methyl radicals generated on the surface of the BDD electrodes. As a result, the sp3 diamond...

Cancer stem cells (CSCs) have enhanced mechanisms of protection from oxidative stress. A variant form of CD44 (CD44v), a major CSC marker, was shown to interact with xCT, a subunit of cystine-glutamate transporter, which maintains high levels of intracellular reduced glutathione (GSH) which defend the cell against oxidative stress. Sulfasalazine (SSZ) is an inhibitor of xCT and was shown to suppress the survival of CD44v-positive stem-like cancer cells both in vitro and in vivo. To find the dose of SSZ which can safely reduce the population of CD44v-positive cells in tumors, a dose-escalation study in patients with advanced gastric cancer was conducted.SSZ was given four times daily by oral administration with 2 weeks as one cycle. Tumor biopsies were obtained before and after 14 days of administration of SSZ to evaluate expression of CD44v and the intratumoral level of GSH.Eleven patients were enrolled and received a dosage from 8 to 12 g/day. Safety was confirmed up to a dosage of 12 g/day, which was considered the maximum tolerated dose. Among the eight patients with CD44v-positive cells in their pretreatment biopsy samples, the CD44v-positive cancer cell population appeared to be reduced in the posttreatment biopsy tissues of four patients. Intratumoral GSH levels were also decreased in two patients, suggesting biological effectiveness of SSZ at 8 g/day or greater.This is the first study of SSZ as an xCT inhibitor for targeting CSCs. Reduction of the levels of CD44v-positive cells and GSH was observed in some patients, consistent with the mode of action of SSZ in CSCs.

Boron-doped diamond (BDD) microelectrodes were used to observe the correlation between electrocatalytic currents caused by individual Pt nanoparticle (Pt-np) collisions at the electrode. The BDD microelectrodes, ∼20 µm diameter and ∼2 µm particle size, were fabricated at the surface of tungsten wires. Pt-np with a size of 1 to 5 nm with agglomerations up to 20 nm was used for observation. The electrolytic currents were observed via catalytic reaction of 15 mM hydrazine in 50 mM phosphate buffer solution at Pt-np at 0.4 V when it collides with the surface of the microelectrodes. The low current noise and wider potential window in the measurements using BDD microelectrode produced a better results, which represents a better correlation to the TEM result of the Pt-np, compared to when gold microelectrodes was used.

Biomolecule modified magnetic beads has been widely used in separation and sensing process. This study used streptavidin modified magnetic beads to immobilize biotin modified zanamivir. Biotin-streptavidin affinity facilitates immobilization of zanamivir on magnetic beads. Then interaction of zanamivir and neuraminidase was adopted as basic for enzyme detection. Detection of neuraminidase was performed at gold modified BDD using cyclic voltammetry technique. The measurement was carried out based on alteration of electrochemical signals of working electrode as neuraminidase response. The result showed that zanamivir was successfully immobilized on magnetic beads. The optimum amount of magnetic beads for zanamivir immobilization was 120 ug. Linear responses of neuraminidase were detected in concentration range of 0-15 mU. Detection limit (LOD) of measurement was 2.32 mU (R2 = 0.959) with precision as % RSD of 1.41%. Measurement of neuraminidase on magnetic beads could be also performed in the presence of mucin matrix. The linearity range was 0-8 mU with LOD of 0.64 mU (R2 = 0.950) and % RSD of 7.25%.

Electroreduction of CO2 was studied at copper-modified boron-doped diamond (Cu-BDD) electrodes as the working electrode. The Cu-BDD electrodes were prepared by electrochemical reduction with various concentrations of CuSO4 solutions. FE-SEM was utilized to characterize the electrodes. At Cu-BDD electrodes, a reduction peak at around -1.2 V (vs Ag/AgCl) attributtable to CO2 reductions could be observed by cyclic voltammetry technique of CO2 bubbled in water containing 0.1M NaCl. Accordingly, electroreduction of CO2 was conducted at -1.2 V (vs Ag/AgCl) using amperometry technique. The chemical products of the electroreduction analyzed by using HPLC showed the formation of formaldehyde, formic acid, and acetic acid at Cu-BDD electrodes.

Cadmium sulphide (CdS) nanoparticles were chemically synthesized using reverse micelles microreactor methods. By using different washing treatments, UV-Vis spectroscopy showed that the absorption peaks appeared at 465 nm, 462 nm, 460 nm, and 459 nm respectively for CdS nanoparticles without and with 1, 2, and 3 times washing treatments using pure water. In comparison with the absorbance peak of bulk CdS at 512 nm, the shifted absorption peaks, indicates that the different sizes of CdS can be prepared. Anodic stripping voltammetry of the CdS nanoparticles was then studied at a boron-doped diamond electrode using 0.1 M KClO4 and 0.1 M HClO4 as the electrolytes. A scan rate of 100 mV/s with a deposition potential of -1000 mV (vs. Ag/AgCl) for 60 s at a potential scan from -1600 mV to +800 mV (vs. Ag/AgCl) was applied as the optimum condition of the measurements. Highly-accurate linear calibration curves (R2 = 0.99) in 0.1 M HClO4 with the sensitivity of 0.075 mA/mM and the limit of detection of 81 µM in 0.1 ...

A novel co-reactant-free electrogenerated chemiluminescence (ECL) system is developed where Ru(bpy)32+ emission is obtained on boron-doped diamond (BDD) electrodes. The method exploits the unique ability of BDD to operate at very high oxidation potential in aqueous solutions and to promote the conversion of inert SO42– into the reactive co-reactant S2O82–. This novel procedure is rather straightforward, not requiring any particular electrode geometry, and since the co-reactant is only generated in situ, the interference with biological samples is minimized. The underlying mechanism is similar to that of the Ru(bpy)32+/S2O82– system; however, the intensity of the emitted signal increases linearly with [SO42–] up to ∼0.6 M, with possible implications for analytical uses of the proposed procedure.

We have developed a lab-on-a-chip (LOC) platform for electrochemical detection and degradation of the pesticide atrazine (Atz). It is based on boron-doped diamond (BDD) electrodes and a competitive magneto-enzyme immunoassay (EIA) that enables high sensitivity. To detect the enzymatic reaction, we employed a BDD electrode modified with platinum nanoparticles (PtNPs), as a highly conductive catalytic transducer. Chronoamperometry revealed a limit of detection (LOD) of 3.5 pM for atrazine, which, to the best of our knowledge, is one of the lowest value published to date. Finally, we degraded Atz in the same platform, using a bare BDD electrode that features remarkable corrosion stability, a wide potential window, and much higher O2 overvoltage as compared to conventional electrodes. These characteristics enable the electrode to produce a greater amount of HO• on the anode surface than do conventional electrodes and consequently, to destroy the pollutant more rapidly. Our new LOC platform might prove interesting as a smart system for detection and remediation of diverse pesticides and other contaminants., The authors acknowledge the support given by MICINN for the project Spain–Japan International Bilateral PIB2010JP-00278 and support from the Severo Ochoa Program (MINECO, Grant SEV-2013-0295).

Gold-modified boron doped diamond (BDD) electrodes were examined for the amperometric detection of oxygen as well as a detector for measuring biochemical oxygen demand (BOD) using Rhodotorula mucilaginosa UICC Y-181. An optimum potential of -0.5 V (vs Ag/AgCl) was applied, and the optimum waiting time was observed to be 20 min. A linear calibration curve for oxygen reduction was achieved with a sensitivity of 1.4 μA mg(-1) L oxygen. Furthermore, a linear calibration curve in the glucose concentration range of 0.1-0.5 mM (equivalent to 10-50 mg L(-1) BOD) was obtained with an estimated detection limit of 4 mg L(-1) BOD. Excellent reproducibility of the BOD sensor was shown with an RSD of 0.9%. Moreover, the BOD sensor showed good tolerance against the presence of copper ions up to a maximum concentration of 0.80 μM (equivalent to 50 ppb). The sensor was applied to BOD measurements of the water from a lake at the University of Indonesia in Jakarta, Indonesia, with results comparable to those made using a standard method for BOD measurement.

The boron-doped diamond (BDD) electrode is known to possess a wide range of applications for the direct generation of hydroxyl radicals and resulting inorganic peroxides such as persulfate, perphosphate, and hypochlorite. In contrast to the extensive use of the BDD electrode in biological and inorganic chemistry, only a few examples exist in which electrochemically generated hydroxyl or alkoxy radicals have been employed to promote reactions of highly functionalized organic substances. The known applications include reactions of relatively simple substrates, such as acetal production by oxidative C C bond cleavage, and BDD-mediated oxidative couplings to construct diaryl linkages. In general, alkoxy radicals, formed by anodic oxidation of the corresponding alcohols, function as mediators in reaction pathways that are different from those occurring under standard electrolysis conditions using carbon or platinum electrodes. Dolson and Swenton have termed reactions that proceed by the generation of methoxy radicals, formed by anodic oxidation of MeOH followed by chemical reaction of the derived radical and ionic species, as EECrCp processes. In a previous effort focusing on the synthesis of ( )-parasitenone (4) (Table 1), we have used an oxidative quantitative dimethoxy-acetalization reaction (1!2), occurring in a basic MeOH solution at a Pt electrode, as the key step (entry 1). A similarly efficient reaction takes place when the BDD electrode is employed (entry 3), while the corresponding aldehyde 3 is produced from 1 in the oxidative reaction occurring on a glassy carbon (GC) electrode (entry 2). The process taking place in a basic MeOH solution (entry 1) might involve the intermediacy of methoxy radicals in the manner described by Swenton. Similarly, reaction at the BDD electrode (entry 3) is anticipated to produce the same radical species. These observations indicated that the acetalization reaction (1!2) at Pt or BDD electrodes proceeds through the EECrCp pathway in which the initially formed arene cation radical intermediate A is converted to a cation B that undergoes addition of methoxide, while the ECEC mechanism proceeds through radical C (Scheme 1). Also, the lack of production of methoxy radicals at the GC electrode enables the initially formed cation radical A to undergo proton loss (to D) in the route for formation of aldehyde 3. Despite the plausibility of the mechanistic pathways suggested for the conversion of 1 to either 2 or 3, no studies exist providing direct proof for the involvement of radical species in processes of this type. In the current study, we have carried out ESR experiments to determine if radical intermediates are generated in electrochemical oxidation reactions of methanol using BDD, Pt, and GC electrodes. In addition, we have probed electrochemical oxidation reactions of isoeugenol (5) as part of the biomimetic preparation of the neolignan, licarin A (6). To gain information about whether or not radical species are involved in electrochemical oxidation reactions conducted in MeOH, we have carried out an ESR study using the radical trapping agent 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) (Scheme 2). Anodic oxidations of methanolic solutions of DMPO were performed employing constant Table 1: Synthesis of ( )-parasitenone (4) using anodic oxidation and electrochemical synthesis of bisketal 2.

Magnetically bistable solid solutions of Prussian blue analogues with chemical formulas of KαNi1–xCox[Fe(CN)6]β·nH2O (Ni1–xCoxFe) and KαCoγ[Fe(CN)6]y[Cr(CN)6]1–y·nH2O (CoFeyCr1–y) have been synthesized and studied using mass spectrometry, Mossbauer spectroscopy, X-ray diffraction, temperature-dependent infrared spectroscopy, and dc magnetometry. These compounds provide insight into interfaces between the photomagnetic Co–Fe Prussian blue analogue and the high-TC Ni–Cr Prussian blue analogue that exist in high-TC photomagnetic heterostructures. This investigation shows that the bistability of Co–Fe is strongly modified by metal substitution, with Ni1–xCoxFe stabilizing high-spin cobalt–iron pairs and CoFeyCr1–y stabilizing low-spin cobalt–iron pairs, while both types of substitution cause a dramatic decrease in the bistability of the material.

Unprecedented anionic Fe(III) spin crossover (SCO) complexes involving a weak-field O,N,O-tridentate ligand were discovered. The SCO transition was evidenced by the temperature variations in magnetic susceptibility, Mossbauer spectrum, and coordination structure. The DFT calculations suggested that larger coefficients on the azo group in the HOMO-1 of a ligand might contribute to the enhancement of a ligand-field splitting energy. The present anionic SCO complex also exhibited the light- induced excited-spin-state trapping effect.

Novel polymorph of the ferric spin crossover complex, β-[Fe(qsal)2]I3 [qsalH = N-(8-quinolyl)salicylaldimine], has been prepared and characterized by magnetic susceptibilities and Mossbauer spectra. β polymorph exhibited a cooperative complete spin transition with a thermal hysteresis of 25 K and a tendency to be quenched in the high-spin (HS) state, which is contrastive to a gradual incomplete spin conversion in α polymorph.

Water-dispersible biotin-modified biofunctional ferromagnetic L1o FePt nanoparticles (NPs) have been synthesized by using a silica nanoreactor strategy. The coercivity field of the NPs was 16 kOe a...

Electrochemical detection of Se4+has been performed by anodic stripping voltammetry on a boron-doped diamond (BDD) electrode modified with gold nanoparticles deposited through chronocoulometry. This method is based on the affinity between the gold nanoparticles and Se0, while the BDD electrode is presented as an ideal material for metal modification due to its unique properties. The resulting anodic stripping voltammograms exhibited a clear peak at 0.9 V versus AgCl related to Se4+, and highly accurate (r2=0.99) calibration curves could be obtained for a selenium concentration range between 10 and 100 μg/L. The influence of Se deposition time and other metals dissolved in solution (Cu, Cd, Pb, Cr, and B) has been investigated as well, and it was found that the Se4+calibration curves remained unaltered. For all the experiments performed, a detection limit around 10 μg/L was achieved. The high accuracy and reproducibility of the results as well as the excellent stability of the electrode material proves the excellent capabilities of this system for selenium detection.

Three novel N,N′-bis(2-hydroxy-3-methoxybenzylidene)-1,3-diaminopropane dimeric lanthanide complexes, namely, [{H2L}Sm(NO3)3]2·H2O (1), [{H2L}Gd(NO3)3]4·CH3OH (2), [{H2L}Lu(NO3)3]4·H2O (3) (H2L = N,N′-bis(2-hydroxy-3-methoxybenzylidene)-1,3-diaminopropane) and three new N,N′-bis(2-hydroxy-3-methoxybenzylidene)-1,3-diaminopropane 3d-Gd heterodinuclear complexes, namely, [{LCo}(CH3COO)(CH3COOH)Gd(NO3)2] (4), [{LNi(MeOH)2}Gd(NO3)3]·2MeOH (5) and [{(L)Zn(HNO3)}Gd(NO3)3]·NO3·H3O·MeOH (6) have been synthesized and isolated. X-ray crystallographical analysis reveals that complexes 1–3 are isomorphic with unique dimeric topology. Complexes 4–6 are of discrete 3d–4f dinuclear cores. Magnetic properties of complexes 2 and 4–6 are systematically investigated. Complexes 4 and 5 are ferromagnetic, while 2 and 6 are antiferromagnetic.

We describe a simple bench top method for fabricating boron-doped diamond (BDD) microband electrodes and copper-modified BDD microband electrodes. The method described here is inexpensive, robust, renewable, simple, and the BDD microband electrodes and the copper-modified BDD microband electrodes are very easy to fabricate. An advantage of the method is not only its simplicity but also the renewability. That is, even if the surface of the electrode is deactivated after an electrochemical reaction, it can be renewed by simply cutting off the end. As one of the example of application, we report on the selective detection of glucose in solution containing interference species such as Ascorbic acid (AA) and Uric acid (UA) by preparing Cu-modified BDD microband electrodes. Even in solutions containing 2 or 3 times the amount of interfering species compared to the glucose concentration, the Cu-modified BDD microband electrodes showed good selectivity and high durability.

The physical and electrochemical properties of boron-doped polycrystalline diamond electrodes, prepared with various B/C ratio, i.e., 0.1%, 0.5% (BDD-A), 1% (BDD-B), and 5% (BDD-C), were investigated. Electrochemical measurements of the heavily boron-doped films (BDD-C) showed giant electric double-layer capacitance and activity which is significantly larger than BDD-A and BDD-B as well as glassy carbon electrodes. However, interestingly, actual boron concentration of BDD-C was observed to be almost the same as that of BDD-B by secondary ion mass spectroscopy (SIMS) and glow discharge optical emission spectroscopy (GDOES) analysis. It is suggested that the large capacitance is due to a few sp2-bonded carbon impurities, which was observed only in BDD-C, although the amount of the sp2-bonded nondiamond species are very small. In the present work, the reason for the interesting electrochemical properties of heavily boron-doped diamond electrodes is discussed. Furthermore, dimensional stability of the electrodes was also confirmed by conducting harsh anodic treatment.

Amperometric gas sensor of arsine was developed using gold-modified diamond electrodes as the working electrodes. The detection method was conducted in high concentration of H 2 SO 4 . The reaction was declared based on two oxidation steps, involving oxidation of As 3− to As 0 at mild potential in strong acid, followed by electrochemical oxidation of As 0 to As 3+ at gold-based electrodes. Linear calibration curve was observed in the concentration range of 5–50 ppb ( r 2 = 0.985) with detection limit of ∼4.43 ppb ( S/N = 3). Current decreasing of measurement was found ∼5.5% for 5 measurements. However, better stability was observed after the 5th measurement, indicated that the sensor could be applied for long time measurement. Investigation to several possible interference gasses, i.e. SO 2 , H 2 S, NO, NO 2 , CO, O 3 and H 2 indicated no significant interference of the gas to arsine measurements.

Three Salen-like gadolinium complexes, namely, mononuclear (4f) complex [{H2L}Gd(NO3)3] (1), heterodinuclear (3d–4f) complex [{LCu}Gd(NO3)3]·0.25H2O (2) and dimeric heterotrinuclear (3d–4f–3d′) complex [{LCu}Gd(H2O)3{Fe(CN)6}]2·6H2O (3) [H2L = N,N′-ethylene-bis(3-methoxysalicylideneimine)] have been synthesized by stepwise reactions. X-ray diffraction analysis reveals that 1 is of a discrete structure in which H2L coordinates to gadolinium ion through O2O2 moiety. Then, addition of Cu(Ac)2·H2O to the mononuclear lanthanide complex yields expected heterodinuclear (3d–4f) complexes [{LCu}Gd(NO3)3]. 3 features a unique 1D ladder-like topology structure through the intermolecular double links of Cu–N bonds. The measurement of variable-temperature magnetic susceptibility reveals that complex 1 exhibits antiferromagnetic interaction while 2 and 3 exhibit ferromagnetic interaction between spin carriers. The correlations between the structure and magnetism are described and discussed.

This paper describes the deposition of zinc(II) with anodic stripping voltammetry on the boron-doped diamond electrode. We illustrate the dependency of several parameters on the magnitude of the oxidation peak and try to optimize the method. The supporting electrolyte was found to influence the oxidation peak magnitude. Compared with acetic acid, the most frequently used supporting electrolyte, ammonia buffer solution leads to a four times higher signal. We assume that the formation of zinc complexes, primarily tetraaminezinc(II), are responsible for the better response. Further factors studied and assessed include buffer pH, buffer concentration, deposition potential, deposition time and scan rate. With the improved conditions, a final detection limit of 5 ppb was accomplished.

Two lanthanide-containing 2D coordination polymers, [Ln(H2salen)1.5(NO3)3]n [H2salen = N,N′- ethylenebis(salicylideneimine); Ln = Gd (1), Dy (2)], have been prepared by self-assembly method. The molecular magnetism and luminescence of the metal complexes had been studied. Complex 1 exhibits antiferromagnetic interaction between spin carriers. Complex 2 emits the H2salen ligand luminescence.

Treatments of p-ferrocenylbenzoate [p-NaOOCH4C6Fc, Fc=(η5-C5H5)Fe(η5-C5H4)] with Ln(NO3)3·nH2O afford seven p-ferrocenylbenzoate lanthanide complexes {[Ln(OOCH4C6Fc)2(μ2-OOCH4C6Fc)2(H2O)2](H3O)}n [Ln=Ce (1), Pr (2), Sm (3), Eu (4), Gd (5), Tb (6) and Dy (7)]. X-ray crystallographic analysis reveals that the isomorphous complexes {[Ce(OOCH4C6Fc)2(μ2-OOCH4C6Fc)2(H2O)2](H3O)}n (1) and {[Pr(OOCH4C6Fc)2(μ2-OOCH4C6Fc)2(H2O)2](H3O)}n (2) form a unique 1D double-bridged infinite chain structure bridged by μ2-OOCH4C6Fc groups. Each Ln(III) ion adopts a dodecahedron coordination environment with eight coordinated oxygen atoms from two terminal monodentate coordinated FcC6H4COO− units, two terminal monodentate coordinated H2O molecules and four μ2-−OOCH4C6Fc units. The luminescent spectra reveal that only 4 and 6 exhibit characteristic emissions of lanthanide ions, Eu(III) and Tb(III) ions, respectively. The variable-temperature magnetic properties of 5 and 7 suggest that a ferromagnetic coupling between spin carriers may exist in 5.

We have observed size-reduction induced ferromagnetism and significant photo-magnetic effects in azobezene-thiol-modified gold nanoparticles. When the particle size was reduced to 1.7 nm, ferromagnetism even at room temperature was observed while diamagnetism was dominating with the particle size of 5.0 nm. Furthermore, reducing the particles size to 1.7 nm also gave rise to photo-magnetic properties because the decrease in particle size provided free volume between each of the azobenzene ligands. This photo-magnetic effect could be attributed to photo-induced changes in the values of d-charge losses due to the photoisomerization of azo-ligands, which were accompanied by the inversion of surface dipole values to the opposite sign.

A non-enzymatic glucose sensor, consisting of a regular array of nickel microdisks on a diamond electrode substrate designed to control the diffusion processes of glucose and interfering species such as ascorbic acid and uric acid, was fabricated. Each nickel microdisk acts as a microelectrode for glucose (hemispherical diffusion) due to the inactive diamond surface for glucose oxidation while interfering species are oxidized at the diamond surface (linear diffusion). The difference in diffusion profiles gives a difference in the time dependence of the amperometric response. That is, the glucose concentration gives rise to a constant amperometric response whereas the concentration of mixed interfering species gives rise to a time dependent response, because the hemispherical diffusion profile yields a constant response and the linear diffusion profile yields a transient current following Cottrell's equation. The results show that the fabricated electrodes exhibit a high selectivity for glucose in solutions containing ascorbic and uric acids.

The differential pulse voltammetric (DPV) peak for dopamine (DA) oxidation was found to be highly amplified by the addition of ascorbic acid (AA) when carboxyl-terminated boron-doped diamond (BDD) electrodes were used as the working electrode. The DP voltammogram for a solution containing DA and AA obtained using a 4-pentenoic acid-modified BDD (4PA-BDD) electrode showed well-separated oxidation peaks for DA and AA at 0.4 and 0.6 V vs. Ag/AgCl, respectively. In addition, as the DA concentration increased at constant AA concentration, a simultaneous increase in the DA peak current density and decrease in the AA peak current density were observed. The slope of the calibration curve for the [DA] range of 1–10 μM in the presence of AA (500 μM) was seven times larger than that obtained in the absence of AA. Such an enhancement was found to be more efficient at 4PA-BDD than at oxidized-BDD, partly due to simple electrostatic effects and partly due to suppression of the polymerization of DA oxidation products by the terminal carboxyl groups. The enhanced detection method using a carboxyl-terminated BDD electrode should be an effective analytical tool, especially for determining low concentrations of DA in the presence of high concentrations of AA.

Geordnete Verhaltnisse: Assoziate ferromagnetischer FePt-Nanopartikel mit groser senkrechter magnetischer Anisotropie wurden durch magnetfeldgestutzte schichtweise Abscheidung erhalten, und anschliesend wurden geschichtete Filme aus L10-FePt-Nanopartikeln und organischen Polymeren hergestellt. Diese Filme werden bei der Verwendung photochromer Molekule als Polymerschichten photodurchstimmbar.

In this paper, the simplest methods developed so far for the analyses of pH and acid concentrations in acid solution are described, using a technique based on highly boron-doped diamond (BDD) electrodes. These simple analyses take advantage of a very attractive electrochemical property of BDD electrodes, i.e., a very wide potential window. It transpires that the value of the current generated by hydrogen evolution during the reduction of an acid when measured by linear sweep voltammetry (LSV) measurements accurately reflects the proton concentration (pH) when using a BDD macroelectrodes (hereafter designated as BDD-M), whereas accurate measurements are impossible when using conventional electrode materials such as glassy carbon, metal etc because of their narrow potential windows. Furthermore, the measurements of weak acid concentrations [HA] were also possible by using both the pH value (obtained by BDD-M) and the limiting current value obtained by using BDD microelectrodes (hereafter designated as BDD-m).

Magnetic properties of Ni thin films which were modified through the redox reaction in alkaline solution were investigated by means of magneto-optical Faraday effect. The magnetization process of Ni film on which Ni(II) compounds electrochemically forms was different from that of fresh Ni films. This indicates that the magnetic anisotropy is modified through the redox reaction Ni(0)/Ni(II) which may induce the change in the volume of metallic nickel region and/or the magnetic coupling between the metallic Ni and some compound including Ni(II) formed on the film surface. [DOI: 10.1380/ejssnt.2009.787]

Boron-doped diamond (BDD) surfaces were photochemically modified with vinylferrocene (VFC), and the modified surfaces were analyzed both qualitatively and quantitatively by electrochemical techniques. VFC-modified BDD (VFC-BDD) was prepared by ultraviolet (254 nm) irradiation of hydrogen-terminated BDD in mesitylene, acetonitrile, or n-alkane solutions of VFC. Cyclic voltammetry (CV) results indicated facile electron transfer between ferrocenyl groups and the BDD substrate. The surface coverage of VFC-modified polycrystalline and single-crystal (100) BDD was also estimated by CV and was found to reach saturation at a value possibly corresponding to monolayer coverage by ferrocenyl groups. The electrochemical stability of VFC-BDD to successive potential cycling in acetonitrile was found to be much higher than that of a self-assembled ferrocenylalkanethiol monolayer on an Au electrode surface. This study is the first to show that appropriate solutions of a terminal alkene can be used in the photochemical mo...

In this report, we established a new electrochemical method for the detection of conformational changes in large, non-metalloproteins such as bovine serum albumin, using flow injection analysis coupled with hydrogen-terminated, boron-doped diamond electrodes. The oxidation current was used as a signal reporter in the monitoring of urea-induced BSA denaturation. In the denatured state at high urea concentrations, the electrochemical signal increased, and the amperometric responses for the oxidation potential at 1300 mV were consistent with the results of conventional methods of denaturation monitoring using fluorescence spectroscopy. The oxidation involved at least five redox-active species (cysteine, tryptophan, tyrosine, methionine, and disulfide bonds). Furthermore, the method also showed high sensitivity for quantitative analysis of protein. A linear dynamic in the concentration range 50-400 microg/mL (r(2) = 0.977) with a lower detection limit of 190 ng/mL was achieved for BSA. Direct electrochemical detection of conformation changes of proteins using BDD electrodes can be performed with advantages in terms of simplicity and sensitivity.