Temperature-pulse voltammetry

Till now, there is no dedicated thermoelectrochemical instrument on the market which would allow to perform modem thermo-pulse methods like the temperature-pulse voltammetry. Instead of utilising a commercial programmable potentiostat as described above, completely home-built devices like that described in Appendix B are worthwhile to be considered, since easy to use microcontroller boards became available. In the example in Appendix B, a microcontroller board initiates and controls the virtual measurement sequence, whereas an ordinary PC is collecting and plotting the results via an animated EXCEL sheet which also is mimicking a typical control panel. This low-cost arrangement fulfils all requirements even for the most sophisticated modem thermoelectrochemical pulse techniques. 

Fig. 6.9 Pulse diagram (schematic) of two temperature-pulse voltammetry variants. Left Staircase mode right Normal pulse mode, tn and h times of heating pulse cooling-down periods, respectively. S potential step amplitude. AE potential pulse amplitude in normal pulse mode. From [6], with permission...

Appendix B A Home-Built Device for Temperature-Pulse Voltammetry... 

The instrument should be capable of performing all the classic electrochemical methods such as cyclic voltammetry, potentiometry, chronoamperometry, chronopotentiometry, etc., and additionally modem thermoelectrochemical methods such as temperature pulse voltammetry. 

Fig. B8 Virtual control panel for temperature pulse voltammetry. The curves are composed of single current samples measured at the end of heating pulses. The three resulting temperature pulse voltammograms shown correspond to three different heating temperature values encountered during the current sampling period. Equimolar solution of 5 mM ferro- and fenicyanide in 0.1 M KCl. Pt wire electrode (diameter 25 pm). Temperature values (for curves with current in increasing order) 24 °C, 64 °C and 120 °C. Potential shift with temperature (—1.6 mV K ) as well as increase of diffusion coefficient with T is visible...

In addition to the traditional SEV techniques discussed earlier, various pulse volt-ammetric techniques have been employed at solid electrodes in molten salts, especially in the room-temperature haloaluminate melts. Numerous pulse techniques have been devised, and some of the more common examples of this family of volt-ammetric methods are described in Chapters 3 and 5 of this volume. However, the application of these methods to molten salts is limited primarily to large amplitude pulse voltammetry (LAPV), differential-pulse voltammetry (DPV), and, more recently, reverse normal-pulse voltammetry (RNPV). The application of LAPV and... 

Jan. 20, 1927, Cleveland, Ohio, USA - Aug. 10, 2004, Raleigh, NC, USA) Osteryoung received his bachelor s education at Ohio University and his Ph.D. at the University of Illinois. He was professor and Chairman of the Chemistry Department at Colorado State University, a professor at the State University of New York at Buffalo and research professor and Chair of the Department of Chemistry of North Carolina State University. He published about 225 original scientific papers, and was especially known for his papers on double potential step -> chronocoulometry, -> square-wave voltammetry, and room-temperature molten salt electrochemistry. He also initiated computer-controlled electrochemical measurements, which helped in developing and optimizing - pulse voltammetry. He served as an Associate Editor for the journal Analytical Chemistry. 

Mix fsDNA solution and H33258 at a final concentration of 1 pM in 50mM PBS and pipet an aliquot (20 pL) of this mixture on the gold or carbon SPE surface. Measure immediately using linear sweep voltammetry (LSV) after an equilibration time of 10s, with a sample interval of lmV, and a scan rate of 0.1 V/s from 0 to IV (Fig. 5). Alternatively, cyclic voltammetry (CV) can be applied with a scan range between 0 and 1V at a sweep rate of 0.1 V/s. For differential pulse voltammetry (DPV) measurements, the potential is scanned from 0 to 0.90V with a step potential of 4mV, pulse amplitude of 50mV, and a pulse period of 0.20s at a scan rate of lOmV/s. The current height is recorded at the peak potential (-0.6V) for analytical evaluation of the measurements. All measurements should be carried out at room temperature. 

Figure 7.3 Label-free voltammetry of 10 nM IgE on a multiwalled carbon nanotube (MWCNT)-modified screen-printed carbon electrode (solid line) and on a bare screen-printed carbon electrode (dashed line). Experimental conditions for differential pulse voltammetry were as described in Figure 7.2. MWCNTs (1 mg) were dispersed with the aid of ultrasonic agitation in 10 mL of N, Ai-dimethylformamide to give a 0.1-mg mL black solution. MWCNT film was prepared by pipetting a 2- xL drop of MWCNT solution onto the carbon working electrode of the screen-printed electrode and then evaporating the solvent at room temperature.

Fig. 6 Influence of temperature on limiting current from normal pulse voltammetry (pulse width 10 ms) for Mb-DDAB films on PG in pH 5.5 buffer (adapted from Ref. [19])...

Fig. 14 Optimization of hybridization conditions, (A) Plot of peak current response vs. incubation time (t from 10 min to 40 min), (B) Effect of hybridization temperature (from 40°Cto 70 °C), The differential pulse voltammetry peak current of CA-MB was detected in 0,1 M phosphate buffer saline solution pH 7,3, Reproduced from Li with permission... 

DDAB films are in a lamellar liquid crystal phase at 25 C. The fluidity of this phase facilitates movement of the protein during voltammetry. In thick films, normal pulse voltammetry (NPV) limiting currents, a direct measure of [11,17] gave small NPV limiting currents for Mb-DD AB films at temperatures below the gel-to-Iiquid crystal phase transition temperature (T. ), where they are... 

Very recently a differential pulse voltammetry device has been developed through imprinting smart polymers. In this experiment, which was described by N. Karimian et al, a temperature sensitive amine-terminated poly (N-isopropylacrylamide) block, and (N,N -methylenebisacryl amide) cross-linker with o-phenylenediamine were electropolymerised on the surface of a gold electrode, using folic acid as the template. This led to a thermally switchable MIP sensor with selectivity towards the template [355]. 

Isomers of tocopherols in edible oils were quantified using electrochemical methods polarography (Smith et al., 1941), and differential pulse voltammetry (Galeano et al., 2004 Robledo et al., 2013). A couple of spectrophotometric assays were used to quantify tocopherols copper(II)-neocuproin system (Tiitem et al., 1997). GC-MS analysis reveals the instability at heating of y-tocopherol Ifom com oil. This isoform is converted to a-tocopherol and later degraded when temperature is increased (Sim et al., 2014). 

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