Charge generation ionic charging

Ion chromatography. The mobile phase in this type of chromatography is a buffered solution and the stationary phase consists of spherical particles of a polymer, micrometres in diameter. The surface of the particles is modified chemically in order to generate ionic sites. These phases allow the exchange of their mobile counter ion, with ions of the same charge present in the sample. This separation relies on the coefficient of ionic distribution. 

Mass spectrometric detectors for capillary electrophoresis are necessarily post-column detectors and must be interfaced to the cathodic end of the capillary. These detectors consist of four main components the interface, that joins the capillary to the ion source, the ion source, that generates ionic fragments from neutral analyte species, the mass analyzer, that distinguishes ions by their mass/charge (m/z) values, and the ion detector, that measures and amplifies the signal. The principles and instrumentation of bioanalytical MS are explained in Chapter 15. 

The molecular conformation of a macromolecule is one of the fundamental physical properties of polymers, since it controls macroscopic properties, such as viscosity or solubility. There have been many attempts to stimulate reversible changes in polymer conformation under controlled and reproducible conditions in order to create responsive polymers. One approach is to induce a structural change in photosensitive groups incorporated into the polymer chains, such as a trans-cis isomerization. Another method is to generate ionic charges along the polymer chains. The repulsive interactions thus created force the chain to adopt a different conformation. 

Many different enzymatic reactions are accompanied by changes in conductance. Amidases generate ionic groups, and phosphatases and sulphatases change the volume of charge carrying groups. All these reactions and others can be used in biosensors. 

Dispersing a dielectric substance such as A1203 in Lil [34] enhances the ionic conductivity of Lil about two orders of magnitude. The smaller the particle size of the dielectrics, the larger is the effect. This phenomenon is explained on the basis that the space-charge layer consists of or Li, generated at the interface between the ionic conductor (Lil) and the dielectric material (A1203) [35],... 

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