Non-specific elution

A wide range of mobile phase additives can be used in non-specific elution. In this elution nature of the target-ligand interaction is changed. This can be achieved by several ways such... 

Non-specific Elution (Change of buffer pH or buffer ionic strength) ... 

Non-specific elution conditions (e.g., solvents, pH step) are used more frequently because of their broader applicability. Unfortunately, they often lead to some activity losses, even when optimized. The user has to decide whether to try a repeated use (regeneration) or to consider the cartridges as disposable. In routine applications. 

The popularity of reversed-phase liquid chromatography (RPC) is easily explained by its unmatched simplicity, versatility and scope [15,22,50,52,71,149,288-290]. Neutral and ionic solutes can be separated simultaneously and the rapid equilibration of the stationary phase with changes in mobile phase composition allows gradient elution techniques to be used routinely. Secondary chemical equilibria, such as ion suppression, ion-pair formation, metal complexatlon, and micelle formation are easily exploited in RPC to optimize separation selectivity and to augment changes availaple from varying the mobile phase solvent composition. Retention in RPC, at least in the accepted ideal sense, occurs by non-specific hydrophobic interactions of the solute with the... 

Interference occurs when compounds co-elute with the analytes and are not detected directly by a specific detector. The effect is to create negative peaks or an erratic response for the analyte. This problem can be identified by using a non-specific detector such as an ion trap MS detector, an MS in the electron impact ionization mode, or a flame ionization GC detector. 

As is common to all affinity chromatography protocols, only the desired protein is supposed to bind to the column. The target protein then has to be eluted off the column, in this case with 0.5 m imidazole which displaces the imidazole rings of the histidine residues of the target protein. Non-specific binding is often observed, which results in several intermittent washing steps being required as well as optimization of the protocol for each protein. 

It was found that the polymer exhibited selectivity towards phosphomonoester dianions. Less polar compounds were found to bind non-specifically to the polymer. The polymer was then used as a stationary phase for a HPLC column. A mixture containing dA, 5 -dAMP and 3, 5 -cAMP was thus separated. As expected, the retention time of 5 -AMP was larger than those for dA and 3, 5 -cAMP. The same was tme for other nucleotides compared to the corresponding nucleosides. When the Zn2+-free control polymer was used, all compounds were immediately eluted. The possibility to use polymer-anchored recognition units to separate biologically important phosphates was thus proved. 

To ascertain the relative configurations of the dimers, each was synthesized specifically, using protecting groups that allow directed formation of disulfide bonds. Comparison of retention behavior of the specifically synthesized dimers with those synthesized non-specifically showed that F2 corresponds to the antiparallel dimer (Fig. 1) and the slower eluting component to the parallel isomer. 

In contrast, the electrochemical detector responds only to substances that can be oxidized or reduced and thus, providing the mobile phase is free of such materials, it will only detect oxidizable or reducible substances when they are eluted. It follows that this detector is not only a solute property detector but is also a specific detector. The electrical conductivity detector is a non-specific detector and used widely in ion chromatography where it occupies a unique and almost exclusive position. In contrast, the electrochemical detector, in its... 

The surface polarities of M0S2 and sulphided Co-Mo catalysts, estimated from differences in the adsorption of alkanes and aromatic hydrocarbons at 473 K, decreased in the order of AI2O3 > Co-Mo/AI2O3 >MoS2- The non-specificity of the M0S2 surface was similar to that of graphitized carbon both acids and anilines were easily eluted from M0S2 The surface polarities correlated with activities for H2S elimination from saturated S compounds. 

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