Carrier electrolyte

Bachmartn, K., Boden, J., and Haumann, I., Indirect fluorimetric detection of alkali and alkaline earth metal ions in capillary zone electrophoresis with cerium (III) as carrier electrolyte, /. Chromatogr., 626, 259, 1992. 

The determination of chloride using an instrument known as a chloride meter is probably the most common application of coulometry in biochemistry. The instrument is designed to generate silver ions electrolytically from a silver anode. These ions are removed from the solution as undissociated silver chloride, which is either deposited on the anode or precipitated in the solution. A low concentration of carrier electrolyte (nitrate ions) permits a small current... 

Hilder, E. R, Klampfl, C. W., Buchberger, W., and Haddad, P. R. (2002). Comparison of aqueous and nonaqueous carrier electrolytes for the separation of penicillin V and related substances by capillary electrophoresis with UV and mass spectrometric detection. Electrophoresis 23, 414—420. 

The one-electron reduction of 3,4,5-trimethoxyphenyl glyoxal with potassium tert-butoxide in DMSO gives rise mainly to the ctT-semidione, whereas on electrolysis in dimethylformamide, in the presence of tetraethylammonium perchlorate as the carrier electrolyte, the main product is the trans isomer (Sundaresan and Wallwork 1972 Scheme 3.47). 

When a tetraalkylammonium cation is used as a counterion in solvents of high polarity, such as AN or DME, the alkyl groups of the cation hinder the mutual approach of species with different charges. Ion pairs with the potassium cation are stable. This follows from a comparison of the polarographic behavior of the three isomeric dinitrobenzenes in the same solvent (DMF) using tetraethylammonium or potassium perchlorate as the carrier electrolyte (Todres 1970). The halfwave potentials corresponding to the conversion of p- and m-dinitrobenzenes into anion-radicals are independent of whether tetraethylammonium or potassium counterions are employed. The anion-radical is formed from o-dinitrobenzene at a potential that is less negative by almost 100 mV when... 

A linear relationship between peak current and salicylate concentration in 0.1 M NaOH carrier electrolyte was found for the range 8 X 10-6 M to 1 X 10 2 M with a sensitivity of 2.5 /xA/mM. 

Polarographic data for pseudoazulenes 26, 27, 39, and 40 have been reported.51 Reduction of azalenes 26 and 39 at a dropping mercury electrode using tetrabutylammonium perchlorate as the carrier electrolyte in acetoni-... 

The electrophoretic separation technique is based on the principle that, under the influence of an applied potential field, different species in solution will migrate at different velocities from one another. When an external electric field is applied to a solution of charged species, each ion moves toward the electrode of opposite charge. The velocities of the migrating species depend not only on the electric field, but also on the shapes of the species and their environmment. Historically, electrophoresis has been performed on a support medium such as a semisolid slab gel or in nongel support media such as paper or cellulose acetate. The support media provide the physical support and mechanical stability for the fluidic buffer system. Capillary electrophoresis (CE) has emerged as an alternative form of electrophoresis, where the capillary wall provides the mechanical stability for the carrier electrolyte. Capillary electrophoresis is the collective term which incorporates all of the electrophoretic modes that are performed within a capillary. 

Carrier electrolyte or buffer Eluent or mobile phase... 

C. Electromigration Dispersion Electromigration dispersion manifests itself in the form of either fronting or tailing peaks, as shown in Figure 4.8. The peak shapes occur as a result of conductivity differences between the analyte zones and the carrier electrolyte (buffer). Conductivity differences... 

The mobility of the ions is determined by their extent of dissociation in the carrier electrolyte and therefore by its pH. The largest migration differences are obtained when the buffer pH lies between the pK values of the sample components. The pH range between 2 and 12 can be exploited. At lower and higher pH values the current transport is overtaken by hydrogen or hydroxide ions, respectively. Due to their very high mobilities, only very low buffer concentrations can be... 

In electrochemistry, potentials between two phases, originating from adsorption-desorption processes, i.e. potentials at relaxed Interfaces, are sometimes called open circuit potentials. As the experiments should be carried out In excess electrolyte, the activity coefficients are determined by the carrier electrolyte, and therefore are Independent of the concentration of cd electroljrte, i.e. dlna - dlnc j, which is actually measured. So,... 

Let it first be repeated that is the Volta potential of the monolayer minus the same of the carrier electrolyte, and not that of pure water. In fig. 11.3.75 (sec. 11.3.1 Of) it was shown that most simple electrolytes make the water surface more negative. The reason is that in electrolytes such as alkali chlorides and nitrates, the anions are usually more easily dehydrated than the cations, so that they enrich the surface (KF is an exception). Creation of this negative potential is mainly determined by the anion the bigger it is, the larger the effect. Cation specificity is only a minor effect. For simple carboxylates, like K2CO3 or KHCO3 the surface must also be negative with respect to the bulk. The observation that V ° < 0 for the three... 

The solution contained within the capillary in which the separation occurs is known as the background electrolyte (BGE), carrier electrolyte, or, simply, the buffer. The BGE always contains a buffer because pH control is the most important parameter in electrophoresis. The pH may affect the charge and thus the mobility of an ionizable solute. The electro-osmotic flow (EOF) is also affected by the buffer pH. Table 1 contains a list of buffers that may prove useful in high-performance capillary electrophoresis (HPCE). As will be seen later, only a few of these buffers are necessary for most separations. 

Hjerten studied conductivity differences at boundary between analyte zone and carrier electrolyte. 

A polarographic study of a pyridine solution of the quadrivalent (LXI), using 0.05 M lithium bromide as a carrier electrolyte, showed two reduction steps with half-wave potentials at —0.76 and —0.94 volt, ascribed to the... 

The source and destination vials as well as the inside of the capillary are filled with a buffer, also referred to as carrier electrolyte or background electrolyte. The purpose of the buffer is to maintain the pH as well as the conductivity during the electrophoretic separation. A controlled pH is crucial for maintaining a constant net charge on the biomolecules and, thus, maintaining their electrophoretic mobility A controlled conductivity is required so that Joule heating can be controlled. Buffer concentrations in CE are typically in the order 10-100 mM. 

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