Effect of Basic Amino Acids on Nickel Ion Reduction at a Mercury Electrode

Abstract

In a 0.02 M borax solution (pH 8.5), basic amino acids (arginine, lysine, and ornithine) react with Ni 2þ to form a monoligand complex that is reduced at a mercury electrode at about À 0.85 V vs. Ag j AgCl j KCl (3 M). At a long time scale (staircase voltammetry; scan rate < 50 mV s À1 ), the complex reduction is a catalytic (EC') process, the ratedetermining step being the regeneration of the reducible species by the reaction of the amino acid with free Ni 2þ . At a short time scale (differential pulse voltammetry or higher scan rate staircase voltammetry), the reaction rate is controlled by the diffusion of the complex. Although the same kind of complexation occurs with either basic amino acids or glycine, the last one does not induce a similar process. The peculiar effect of basic amino acids is due to the side chain that causes the ligand molecule to adopt a favorable orientation at the electrode surface. The differential pulse voltammetry peak current is proportional to the total amino acid concentration over the concentration range from 2 to 100 mM. Hence a voltammetric method for arginine determination in nutritional supplements was developed and validated using HPLC as reference method.

Improved electroanalytical characteristics for flumetralin determination in the presence of surface active compound

“…On the other hand, the use of modern voltammetric techniques is rather fast, low-cost, and sensitive; therefore, it enables to use them in monitoring of electrochemically active compounds. Several different types of techniques [14–16] and working electrodes [17] have been proposed so far. Among them, the use of square wave voltammetry (SWV), especially in combination with accumulation, is often proposed [18–22].…”

Voltammetric behaviour and quantitative determination of pesticide iminoctadine

“…9 Moreover, Pang reported that guazatine cannot be determined by GC-MS and LC-MS-MS. 10 In the current paper, we present a study of iminoctadine on a Hg(Ag) FE under conditions of square-wave voltammetry (SWV). Square-wave voltammetry 11,12 is nowadays one of the most advanced pulse voltammetric techniques for analytical application, [13][14][15][16] mechanistic [17][18][19] and kinetic studies of electrode processes. [20][21][22][23] In the last two decades the majority of published voltammetric methods was based on the mercury electrodes.…”

Electrocatalytic oxidation and electrochemical detection of guanine,l-arginine andl-lysine at a copper nanoparticles-modified electrode

“…32 Several methods have been developed for the analysis of L-lysine, including liquid chromatography, 33,34 L-lysine a-oxidasebased biosensors, [35][36][37][38] microbial biosensors, 39 electrochemiluminescence, 40 and an assembled microuidic device. 41 In addition, the methods of electrophoresis, 42 differential pulse voltammetry at a mercury electrode, 43 urease-based ion-selective eld effect transistor biosensors, 44 liquid chromatography tandem mass spectrometry, 45 and conductometric bi-enzyme biosensors 46 were proposed for the analysis of L-arginine.…”