Organic molecules, voltammetry

The majority of the works with HgCFMEs focused on the anodic stripping of metals [127]. However, our works have been mainly focused on the determination of organic molecules that show the ability of adsorption on mercury [119-121], for example pteridines. Therefore, those molecules can be primarily preconcentrated on HgCFMEs and, subsequently, determined by cathodic stripping techniques. This procedure is described like adsorptive stripping voltammetry and it is a very interesting technique for trace and ultratrace analysis due to its... 

A series of SAMs formed on Au from mono- and dithiol conjugated aromatic molecules was characterized by cyclic voltammetry, grazing incidence Fourier transform infrared spectroscopy, contact angle measurement, and ellipsometry.43 The analyses indicated that the molecular orientation of conjugated phenylene- and thophene-based dithiols became less tilted with respect to the surface normal as the chain length of the organic molecules increased. 

The family of Ru(II)-Cp ATRA catalysts was recently extended to novel ruthenium amidinate complexes 12 and 13 [40]. Complex 12 displays two successive one-electron oxidation waves in cyclic voltammetry, assigned to Ru(II)/Ru(III) and Ru(III)/Ru(IV) oxidation steps, respectively. This opens the door to chemical transformations of organic molecules on 12 either byway of one-electron redox processes [i.e.,Ru(II) to Ru(III) or Ru(III) to Ru(IV)],or via two-electron processes [i.e., Ru(II) to Ru(IV)]. 

An advantage of voltammetry over AAS is the ability to distinguish an element in different valence states. Eor example, iron Ee + can be quantified apart from Fe (cf Figure 20.4). Some organic molecules are equally electroactive and can be analysed by this method. 

The adsorption of organic molecules with different functional groups on Cu(lll) in a 0.1 M HCIO4 solution was investigated in situ by cyclic voltammetry. The molecules of CYA and cyanuric chloride (CC) adsorb on the Cu(lll) electrode surface and form well-defined adlayers with (3 x 3) structure in the double-layer potential region. The results were compared with those obtained on aromatic and heterocyclic molecular adlayers <2002PCB11272>. 

Cyclic voltammetry provides a profound insight into the redox reactions of organic molecules. In this technique, the potential is scanned from an initial... 

These examples are intended to illustrate how variation of the potential scan rate and the potential limits allows cyclic voltammetry to be used to rapidly build up a picture of the electrochemistry of the organic molecules. 

It is also possible to use 3 0 Voltammetry for the elucidation of adsorption processes of organic molecules on... 

In adsorptive stripping voltammetry (AdSV) metal chelates and organic molecules are accumulated by adsorption at the surface of the working electrode. If these compounds are electrochemically active, i.e., if they are reducible or oxidizable. their subsequent voltammetric determination is possible. By this principle of so-called adsorptive stripping voltammetry, organic and organomet-allic compounds are determined in the ultra-trace range. This technique is particularly important for the trace analysis of metals that are not readily deposited as the element on mercury electrodes... 

Pulse polarography and stripping voltammetry are considered as methods of choice for the quantification of environmentally significant organic molecules (carbonyls, nitroaromatics, phenols, carboxylic acids, sulfonates, azomethines, thiols, amines, etc.) using electrochemical sensors with chemical recognition [28]. The current capabilities of biosensors for organic pollutants analysis are discussed by [7]. 

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