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An instrument for electroanalysis extended to thermoelectrochemical studies is presented here consisting of easily available components. An analog potentiostat is combined with a microcontroller. The latter is controlled by an Excel sheet extended by macros written in VBA (visual basic for applications). The worksheet acts as a virtual instrument with front panel and command buttons. Thus, specialized, expansive measuring software packages are unnecessary. The design of new techniques is facilitated by a of graphical representation of pulse sequences or the exciting waveforms. The instrument has proved to be useful for design and performance of non conventional electrochemical techniques working with additional parameters like irradiation or heat. Examples are given for thermoelectrochemical measuring sequences like TPV (temperature pulse voltammetry).

We describe a novel instrument and electrical circuit for sensitive electrochemical measurements at simultaneous direct electrode heating. The new measuring principle can be applied to working electrodes of various designs featuring two end contacts. In our experiments, the contacts were connected to a 100 kHz AC heating power supply and the potentiostat via the new inductor bridge circuit. A compact heating-generator housing contains all components necessary for sine wave generation as well as amplification and transformation of the heating power. The new arrangement yields high temperature cyclovoltammetric signals for the [Fe(CN)6]3−/4− redox system with a noise level superior to the earlier symmetrically branched wire electrode designs. Noise and disturbances are dramatically suppressed especially for high resistance electrodes such as glassy carbon electrodes. Without a center contact, the working electrode design is greatly simplified. This opens new opportunities for the design of a great variety of heated electrodes that may be arranged in arrays or consist of materials with relatively high resistivity such as carbon and conducting polymers.

The bismuth electrode exhibits similar electrochemical properties as most commonly used toxic mercury electrode and represents a suitable, reliable and also environmentally friendly tool for the detection of electroactive compounds at negative potentials. A wide operational potential window of the bismuth electrode from −200 mV to −1400 mV (vs. SCE) was found. Bismuth bulk electrodes (BiBE) are very convenient for sensitive adsorptive stripping voltammetric (AdSV) determination of the drug daunomycin in the nmol/L concentration range. In comparison with gold electrodes, the voltammetric signals of daunomycin at the bismuth electrode are higher and very well shaped. An accumulation potential of −0.65 V (vs. SCE) and accumulation time from 2 to 10 min were found to be optimal conditions for the preconcentration of daunomycin on the bismuth electrode surface. The adsorptive stripping response is linear over 100–1000 nmol/L concentration range (for 2 min deposition) and over 10–100 nmol/L concentration range (for 5 min deposition) with a detection limit of 5 nmol/L (for 8 min deposition). Repeatability was characterized by relative standard deviation 7.1% (for 10 measurements). The electrode must be regenerated between two consecutive measurements by polishing on a damp paper or by stirring in 96% ethanol for 5 min.

The technique of electrically heated carbon paste electrodes is applied for label-free detection of DNA hybridization after magnetic isolation. Coupling of both techniques leads to highly selective and sensitive detection of DNA hybridization. Minimal contributions of nonhybridized DNA are thus coupled to an enhanced signal. Application of elevated temperatures during the accumulation step yields a max. 6-fold enhancement of guanine oxidation signals compared to room temperature deposition. Use of noncomplementary nucleic acids gives no significant peaks at room or elevated temperatures. The noise level remained unaffected. Variation of the target concentration results in linear calibration plots under hot accumulation conditions.

Mercaptoundecanoic acid (MUA) and glutathione (GSH) self-assembled monolayers were prepared on gold- wire microelectrode. Cyclic voltammetry was used to investigate the influence of temperature on electrochemical behaviors of Fe(CN)63−/4− and Ru(NH3)63+/2+ at these SAMs modified electrodes in aqueous solution. It is found that temperature shows great influence on electron transfer (ET) and mass transport (MT) for the two SAMs modified electrodes and the influence of temperature depends on the charge properties of the redox couples and terminal groups of SAMs and the structure of the monolayer on gold surface. The temperature can greatly increase MT rate of Fe(CN)63−/4− at both MUA and GSH modified electrodes. However, the increased MT rate doesn't have any effect on the CV's for Fe(CN)63−/4− /MUA system. For Ru(NH3)63+/2+ , temperature can greatly improve the electrochemical reaction in both MUA and GSH modified electrodes, which is ascribed to temperature-induced diffusion and convection and the electrostatic interaction between Ru(NH3)63+/2+ and negatively charged carboxyl groups on the electrode surface.

The technologic basis for in situ heating of a microelectrode wire by high amplitude, high frequency alternating current (hot-wire electrochemistry) is presented. The preferred modes are continuous heating until a stationary temperature value is established, and pulsed heating with short time current sampling. The latter allows measurement above the boiling point.

A galvanic cell for trace determination of hydrogen sulfide in gases is presented. The cell covers the range from 30 ppb to some hundred ppm. It is characterized by simple construction. The use of ferricyanide/ferrocyanide ions as a redox mediator system ensures very low cross sensitivity. The sensor is well-suited for mobile use.

It has been investigated how increased temperatures affect the deposition and stripping step during stripping analysis of Cu(II), Hg(II) and As(III). Results obtained at a heated gold wire have been compared to those obtained at a rotating gold disk electrode. The sensitivity has been found to be higher at the hot-wire electrode. The signal-to-noise ratio was also better at the heated gold wire. The lowest Cu(II) concentration detectable was 10−9 mol/L at the heated gold wire compared to 10−7 mol/L at the rotating disk. Comparing the results and executing a protocol consisting of three consecutive scans after one single deposition w/o heat with all three elements showed a quite different behavior. Best signals have been obtained if only conditioning and deposition are done at increased temperature. Deposit is also removed more efficiently during the first scan in this case. Reasons for this are discussed.

This article introduces a new heated mercury film electrode based on a screen-printed carbon substrate. The sensor is easy-to-build and the material costs compared to its iridium-based counterpart are low. The development procedure including electrode construction, mercury deposition and thermal properties is described in detail. As first application, cadmium and lead were determined by square-wave anodic stripping voltammetry with significantly improved signal-to-noise characteristics.

The electrodeposition of lead on boron-doped diamond has been studied with a view to identifying the fundamental parameters controlling the sensitivity and lower detection limit in anodic stripping voltammetry. Chronoamperometric transients are used to explore the deposition, indicating a progressive growth mechanism confirmed by ex situ AFM images. Linear sweep ASV experiments show a threshold concentration of ca 10−6 M below which no lead is detected; this is attributed to the need for nucleation of the solid phase on the electrode. Experiments with variable temperature show that this threshold can be usefully lowered at elevated temperatures.

Bismuth-coated carbon paste electrodes display an attractive stripping voltammetric behavior which improves greatly upon heating the electrode during the deposition step. Such “hot-electrode” operation leads to a dramatic enhancement of the stripping peaks of lead, cadmium and zinc, while retaining low background currents. The influence of relevant parameters, including the heating current, deposition potential and deposition time is examined. The stripping signals for selected heavy metals result in sharp, well defined and undistorted peaks, with favorable reproducibility (5%). Highly linear calibration plot (correlation coefficient, 0.9986) is observed over the 20–140 μg/L lead range. An estimated detection limit of 3.16 μg/L lead could be observed on the basis of signal-to-noise ratio.