Microelectrodes normal pulse voltammetry

Tacussel and their application by Gonon et al.148 to differential pulse voltammetry (DPV) and differential normal pulse voltammetry (DNPV) in vivo, also called the biopulse technique the microelectrodes are implanted in the living animal brain and variations in the concentrations of some molecules can be followed via the Tacussel PRG 5 and BIPAD instruments (see also the selection of commercial models in Table 3.4). 

Concerning more general application of mercury electrode in the studies on com-plexation equilibria, one should mention the paper by Jaworski et al. [59], who have investigated oxidation of mercury microelectrode in solutions with thiocyanates without any background electrolyte added. In the experiments, normal pulse voltammetry and staircase voltammetry were used. The authors have developed a general procedure for the determination of the stability constants, based on the data taken from the voltammograms. They have applied it to the analysis of Hg(II)-SCN complexes. 

Wightman and his group have continued with studies of this type and have found that using a variant of normal pulse voltammetry is probably preferable to using cyclic voltammetry because the period at the base potential between pulses helps to prevent film formation on the electrode and thus keeps the electrode clean. In this way, the behaviour of an implanted microelectrode remains reproducible over a long period of time, which is important as it is very difficult to reposition an electrode in exactly the same spot after it has been removed for cleaning. 

Fig. 7. Effect of an NO-synthase inhibitor (L-arginine p-nitroanilide) on the differential normal pulse voltammetry measurements obtained at a carbon fiber/[(H20)Fe PWii039] -doped poly(Af-methyl pyrrole)/Nafion microelectrode in the rat brain. Electrochemical recording between 0.4 and 1.35 V (vs. Ag/AgCl) at 10 mVs with one cycle every 2 min. The indicated potential corresponds to the oxidation peak of NO and the zero time indicates the injection of the inhibitor into the rat. (From [150].)...

Osteryoung J and Murphy M M 1991 Normal and reverse pulse voltammetry at small electrodes Microelectrodes Theory and Applications (Nate ASI Series E vol 197) ed M I Montenegro, M A Queiros and J L Daschbach (Dordrecht Kluwer)... 

Osteryoung J and Murphy M M 1991 Normal and reverse pulse voltammetry at small electrodes Microelectrodes ... 

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