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The optimization of electrode properties is an inseparable part of the analytical process which can highly improve the quality of obtained results in electrochemical sensing methods. This paper investigates the role of doping level, morphology and structure of boron-doped diamond (BDD) electrodes in electrochemical sensing of heavy metals in the presence of bismuth. To study the influence of doping level and morphology, a large set of BDD films with varying boron-to-carbon and carbon-to-hydrogen ratios in the deposition gas mixture was grown using hot filament chemical vapor deposition method. The set was used for fabrication of electrodes (the active area 0.43 mm 2 was opened in 400 nm SiO 2 by standard optical lithography) for simultaneous electrochemical determination of zinc, cadmium and lead. Square wave anodic stripping voltammetry was utilized for this purpose. The influence of BDD properties on limit of detection (LOD) and sensitivity (S) of the electrodes was also investigated. The highest sensitivity was observed for electrodes prepared with 10 000 ppm boron-to-carbon ratio and lower methane concentrations. The findings prove the importance of selecting an appropriate electrode prior to progressing to electrochemical measurements.

We analyze how the presence of an optical Fabry-Perot cavity affects the surface enhanced Raman (SERS) bands of rhodamine 6G (R6G) in terms of their intensity. The study is focused on the relation between the intensity of the SERS bands and the reflectance which is inherent to the examined structure rather than on the enhancement factor. For this purpose, multilayered Si/SiO2 structures decorated with discontinuous vapour deposited silver films were utilized as an active layer for SERS and a bond for the solution of R6G. We related the intensity of the SERS bands in R6G caused by interference to the reflectances at the wavelengths of the excitation and scattered light.

The unique properties of boron-doped diamond make it a promising electrode material for electroanalytical applications, especially for stripping voltammetry. The boron-doped diamond (BDD) electrodes prepared by chemical vapor deposition (CVD) on alumina substrates were electrochemically characterized by cyclic voltammetry. The influence was investigated of the boron dopant concentration, surface termination as well as chemical surface treatment on the kinetics of the electrode reaction. A standard redox couple, ferro/ferricyanide in aqueous solution, was employed to determine important kinetic parameters (anodic transfer coefficient, diffusion coefficient, and electron transfer rate constants) of the reaction. The effect of surface conditions of the boron-doped diamond electrodes on the kinetics of the electrodeposition of bismuth film was investigated for electrochemical applications in which bismuth film electrodes are utilized. A favourable effect of the cleaning procedures was proved, especially for the oxygen plasma-treated BDD electrode with a higher content of boron in alkaline solution. The anodic current response was increased by 109% when compared with as-grown BDD. The effect of the quality of bismuth film on analytical performance of the voltammetric sensor was verified in simultaneous analysis of heavy metals (Pb, Cd and Zn) by anodic stripping voltammetry.

Electrochemical oxidation of four pharmaceuticals from different therapeutic classes: carbamazepine, diclofenac, trimethoprim and venlafaxine on boron doped diamond electrodes in wastewater was investigated. The influence of basic deposition parameters of boron doped diamond layer (CH4/H2 ratio and boron-to‑carbon concentration (CB-C) in gas phase) as well as surface morphology of the Si substrate was studied. The combination of liquid chromatography-tandem mass spectrometry was used for evaluation of removal efficiency of target compounds. Based on quantitative analyzes, no clear influence of CH4/H2 ratio (in range from 2% to 2.83%; constant CB-C 10,000 ppm) on the removal efficiency was found. An increase CB-C from 10,000 ppm to 15,000 ppm caused a decrease of removal efficiency. The use of boron doped diamond layer grown on structured Si substrate led to a significant increase in removal efficiency (almost 100%). Finally, degradation and transformation products of selected pharmaceuticals were identified by liquid chromatography with high resolution mass spectrometry. Most of the identified oxidation by-products formed during electrochemical oxidation were chlorinated.

A simple, rapid, and sensitive electroanalytical method for the direct quantification of folic acid was developed using square-wave voltammetry with a cathodically pretreated highly boron-doped polycrystalline diamond electrode. The morphology and structure of this electrode were investigated by scanning electron microscopy and Raman spectroscopy. The electrochemical behavior of folic acid was studied by cyclic voltammetry and an irreversible oxidation peak was observed at +0.78 volt vs. Ag/AgCl in Britton-Robinson buffer at pH 5. Using optimized square-wave voltammetric parameter values, the response of folic acid was linear from 0.1 to 167 micromolar with a limit of detection of 30 nanomolar with good repeatability. The influence of some interfering compounds was also evaluated. The method was successfully applied to the quantification of folic acid in pharmaceutical tablets. Considering the importance of the analyte upon human health, the boron-doped diamond electrode may be employed as an effe...

We examined surface enhanced Raman maps of blue writing inks received from commercially available refills and deposited on a rigid silver-nanocrystalline diamond–silicon heterostructure. The heterostructure constituted an active substrate providing a possibility to write directly on the surface and to record Raman maps. Based on rich data containing several thousands of spectra were discriminated between the inks in spite of slight spectral differences. Such discrimination would not be reliable by analyzing single spectra since a number of surface effects contribute to the evolution of Raman bands. We also successfully distinguished the order in which the cross lines of the inks were deposited on the substrate. Raman spectra could not be obtained by conventional Raman spectroscopy; this is why surface-enhanced Raman spectroscopy had to be employed.

Photoelectrochemical (PEC) water splitting provides a promising way for development of sustainable methods of hydrogen generation and water treatment without chemicals. In this paper, we report on the development of a unique PEC electrode consisting of nanostructured p-type boron doped diamond (BDD) layers covered by n-type TiO2 thin film. The influence of nanostructuring and boron doping level, as well as the thickness of TiO2 film on PEC properties, was investigated. As-grown and plasma-nanostructured BDD thin films with two doping levels (B/C = 1 000 ppm and 10 000 ppm in the gas phase) were utilized as substrates for deposition of 20, 100 and 500 nm TiO2 layers using RF magnetron sputtering. The highest photocurrent (60 μA/cm2 and 3.2 mA/cm2 at 0 and 2 V vs Ag/AgCl respectively) was obtained in the case of structured BDD electrode with B/C ratio in gas phase 1 000 ppm, covered by a 500 nm thick TiO2 layer. The experiment confirmed the favorable impact of both nanostructuring and p-n junction, contributing to the hole injection.

Boron doped diamond (BDD) has remarkable physical and chemical properties, that makes it an attractive material for electrochemical applications. In this study, deposition process of BDD on porous carbon foam electrodes was performed by HFCVD method. After depositions, the substrates were not homogenously covered by the BDD thin film only. Depending on the deposition temperature, foam porosity and distance from heated filaments, different carbon nanomaterials were synthesized. The boron doped diamond, graphite nanosheets, carbon nanowalls and its composites occurred on the foams outer and inner surfaces. Two new observed types of carbon structures, the carbon nanowalls – boron doped diamond composite and graphite nanotips are analyzed and described. Analyses were made by SEM and Raman spectroscopy. The influence of deposition conditions on the growth process is discussed.

For the first time, a boron-doped diamond electrode was used as a perspective electrochemical sensor for the sensitive determination of amlodipine, calcium channel blocker drug of 1,4-dihydropyridine type. Cyclic voltammetric studies indicated that the electrochemical oxidation of amlodipine is irreversible with single and well-shaped peak at a potential of +0.75 V ( vs . Ag/AgCl/3 M KCl electrode) in Britton–Robinson buffer solution at pH 5. The effect of supporting electrolyte, pH and scan rate was also examined. The electrode reaction of amlodipine on boron-doped diamond electrode was shown to be a two-electron diffusion-controlled process. Under optimized conditions and using differential pulse voltammetry, the current response of amlodipine was proportional in a concentration range of 0.2–38 μM with two linear segments from 0.2 to 6 μM ( R 2 = 0.996) and from 6 to 38 μM ( R 2 = 0.998), respectively, with a limit of detection of 0.07 μM (28.6 μg L −1 ) and a good repeatability (relative standard deviation of 3.6% at 9.9 μM for n = 20). The practical applicability of the proposed method was demonstrated in the assessment of total content of amlodipine in pharmaceutical tablets with sufficient recoveries in the range of 101.3–104.1%. Additionally, a biological relevance of the developed procedure was demonstrated by analysis of model human urine samples with adequate recoveries (94.1% and 105.7%). The interference study revealed that the use of proposed method in this kind of analysis could be limited depending on the presence of particular excess of some common urinary compounds (uric acid, dopamine, ascorbic acid and glucose). The proposed methodology with boron-doped diamond electrode represents an effective and alternative tool instead of commonly used glassy carbon and chemically-modified electrodes for electrochemical determination of amlodipine.

The surface nanostructuring of boron doped diamond (BDD) can further enhance its unique properties e.g. in electrochemical sensing, photoelectrochemical cells, field emission devices and various kinds of sensors. Here we present an investigation of plasmatic nanostructuring of BDD films without use of a time-consuming masking process. RF plasma technique was used to etch surface nanostructures with dimensions ranging from tenths to hundreds of nm in width and height. The size and shape of achieved diamond nanostructures were influenced only by applied etching parameters. We have found that the etched carbon is re-deposited in an amorphous form creating a mask and this self-masking process is responsible for the final shape of obtained structures. Therefore, this technique is effectively controllable by changing plasma power, gas type and pressure which influence the energy of incident ions and thus the sputtering yield and re-deposition of masking material. Utilization of various gas types, pressures and RF powers revealed the physical type of etching to be dominant over the chemical at both high and low energy ions. The nanostructured surfaces were then observed and characterized by SEM and Raman spectroscopy to investigate the nanostructures dimensions and to confirm the remaining diamond quality.

In this paper we investigate the influence of different metallic (or metal-based) masking materials and plasma techniques on the etching and patterning of polycrystalline boron-doped diamond (BDD) thin films. Lift-off technique was used to prepare various testing mask patterns with dimensions ranging from 1 µm. The results of plasma etching utilizing 100 nm Al and Cu masks are compared. Radio frequency (RF) and Inductively coupled (ICP) pure oxygen plasma techniques were used to obtain the fine etched structures. A simple etching scheme describing the obtained results is presented for each type of the plasma technique and mask type. Although Al mask is widely believed to have outstanding properties over another metallic materials, we have found that the Cu mask exhibits lower side edge etching for the both types of plasma techniques. A formation of thick and crystalline copper oxide layer in contrast with thin amorphous aluminum oxide is believed to be the reason for this behavior. Consequently, the etched structures possessed also a much better side walls angle which is a key parameter e.g. for micro-fabrication of boron doped diamond microelectrodes, microfluidics, sensors and microelectromechanical devices in general.

This paper is focused on the preparation of boron doped diamond (BDD) cantilevers for MEMS applications. Hot filament CVD diamond deposition technique was used for preparation of highly boron doped thin film. The fabrication process consisted only of dry etching steps and masking process, no wet etching of substrate was used. Therefore, it was necessary to optimize both anisotropic and isotropic etching to release the cantilever structure from silicon substrate. Doped diamond cantilevers were etched by reactive ion etching using inductively coupled plasma (ICP RIE) through aluminum etching masks. The optimal properties of fabrication process led to high quality MEMS structures. The resulting cantilevers were investigated by scanning electron microscopy (SEM) and laser vibrometer system. Finally, we demonstrate a BDD cantilever (5 μm width) with the main resonant frequencies at 22.2 kHz, 46.6 kHz, 52.2 kHz and 65.6 kHz.

An electrochemical behavior of methamphetamine on a self-assembled boron-doped diamond electrode was studied by cyclic voltammetry. Methamphetamine yielded a single irreversible oxidation peak at a higher positive potential of +1.23 V (vs. Ag/AgCl/3 M KCl electrode) in Britton-Robinson buffer solution at pH 10. The nature of the electrode reaction was found to be diffusion controlled with minor contribution of adsorption. The differential pulse voltammetric methodology was proposed for the sensitive determination of methamphetamine in a linear concentration range from 0.07 to 80 μM with a detection limit of 0.05 μM (7.46 μg L−1) and a good repeatability (relative standard deviation of 2.8% at 20 μM concentration level, n = 6). The effect of interfering agents (common urinary compounds) was appeared to be negligible confirming a favorable selectivity of method. The practical usefulness of method was demonstrated in the assessment of methamphetamine content in model human urine samples with good accuracy (recoveries varied from 93.4% to 97.6%). The proposed procedure could represent a suitable alternative to other analytical methods for the determination of low concentration levels of methamphetamine in biological samples. It may enable methamphetamine excreted in urine of drug addicted people to be assayed sensitively and selectively.

To meet various application requirements, it is important to enable an improvement of a-C structure and properties, such as hardness, adhesion, and wear resistance. In this study, we used the Raman spectroscopy to investigate the a-C thin films structure dependence on the different deposition parameters. The effect of nitrogen, argon, and hydrogen gas flow rate was analyzed to determine the influence on the film properties. The change in the gas type, combination, and flow had a significant influence on the D and G bands of the a-C Raman spectra. The addition of N2into the chamber promoted the sp2creation, while with adding hydrogen the layer contained more sp3bonds. The depositions of a-C thin films were carried out in pulsed arc discharge vacuum installation. Micro-Raman measurements of the deposited materials were performed using an ISA Dilor-Jobin Yvon-Spex Labram confocal system with 632.8 nm radiation from a He-Ne laser using a back-scattering geometry.

The impact of different doping levels of boron-doped diamond on the surface functionalization was investigated by means of electrochemical reduction of aryldiazonium salts. The grafting efficiency of 4-nitrophenyl groups increased with the boron levels (B/C ratio from 0 to 20 000 ppm). Controlled grafting of nitrophenyldiazonium was used to adjust the amount of immobilized single-stranded DNA strands at the surface and further on the hybridization yield in dependence on the boron doping level. The grafted nitro functions were electrochemically reduced to the amine moieties. Subsequent functionalization with a succinic acid introduced carboxyl groups for subsequent binding of an amino-terminated DNA probe. DNA hybridization significantly depends on the probe density which is in turn dependent on the boron doping level. The proposed approach opens new insights for the design and control of doped diamond surface functionalization for the construction of DNA hybridization assays.

Raman spectroscopy and surface enhanced Raman spectroscopy were used to examine 14 blue inks obtained from commercially available stationery. Standard colouring agents in the inks: β-phase of phtalocyanine blue PB15 and some homologues of the methyl violet class, were identified. Surface enhanced Raman spectra were recorded on a firm heterostructure of silver/nanocrystalline diamond/silicon constituting an active substrate providing the possibility to write directly on the surface. Based on the differences in traditional and surface enhanced Raman spectra, two inks were identified unambiguously, the remaining inks were categorised into three groups exhibiting common spectral features. Despite their similarity, surface enhanced Raman spectra exhibited soft variations enabling discrimination of the inks, thus proving the usefulness of the method.