Apparent mobility

For the separation of enantiomers, we are interested in 0 -0,. Substituting a = I/ KV, using the expression relating the apparent mobility of an analyte to its binding constant with a chiral additive... 

The major surface coat component of Toxocara larvae runs as a set of four closely migrating bands with apparent mobility of 120 kDa on SDS-PAGE. One of these was cloned and sequenced, identified as a serine-rich mucin and designated MUC-1 (Gems and Maizels, 1996). We have now established that there are at least five distinct mucin genes in this parasite, which bear general similarity but important distinctions. Thus, MUC-2, MUC-3, MUC-4 and MUC-5 are all threonine-rich rather than serine-rich, and all five differ in the repeat motifs within the mucin domains. All have similar non-mucin, cysteine-rich domains originally termed NC6 (nematode six-cysteine) domains, and since renamed SXC (six-cysteine), as described below. All mucins have a pair of SXC domains at their C-terminus, while MUC-3 and MUC-5 also have paired N-terminal SXC domains. 

C.M. Wolfe and G.E. Stillman, Apparent Mobility Enhancement in Inhomogeneous Crystals Robert L. Peterson, The Magnetophonon Effect... 

From Eq. 17.26 it is clear that the variance due to longitudinal diffusion is negatively influenced by the length of the capillary and the diffusion coefficient of the solute. However, it is positively affected by the applied potential and the apparent mobility of a solute. According to this equation, fast migrating zones will show less variance due to axial diffusion. 

From Eq. 17.35 it can be observed that N is directly proportional to the applied field strength, the migration distance from injection to detection and the apparent mobility of a solute. The diffusion coefficient and the length of the capillary are inversely related to the efficiency. ... 

In the presence of electroosmotic flow (EOF), the mobility of a given molecule is a combination of its own mobility (which is now called apparent mobility, papp) and the mobility of EOF (pE0F). True mobility is then calculated by subtracting the mobility of EOF from apparent mobility ... 

It is the effective mobility that determines selectivity since the effect of the electroosmotic mobility is equal for all the sample constituents. The effective mobility can be worked out from the apparent mobility if the extent of / eof known. Several methods are applied to determine however, the procedure of applying a neutral marker is commonly used. A marker is a compound that migrates only due to the EOF (neutral). The velocity of a neutral compound represents the velocity of the EOF when no other disturbing processes such as wall adsorption occur. Using the practically obtained migration time of the neutral marker (tgoi) the velocity of the EOF can be calculated ... 

For comparison of impurity levels quoted as % area/area, the normalized PA [area divided by the respective MTs, often stated as corrected PA (Ac)] must be used in CE to compensate for the residence time difference of the species in the detector. In HPLC, the separation takes place on the column. After the column, all analytes travel through the detector at the same speed (that of the mobile phase) and hence have the same residence time in the detector cell. However, in CE, the electrical field also takes effect in the detection cell. Therefore, the residence time of the species that have a higher apparent mobility (as shorter Jm) will give a lower response than species with a lower mobility, for species with the same absorptivity and concentration. ... 

However, it is expected the reaction rates below Tg may be affected also by volume relaxation (physical aging) which was not taken into account and which will result in the dependence of k-p not only on T and a but also on time t. If we take the positive deviations of experiments in Figure 14 as a measure of the volume relaxation effect then the physical aging increases the apparent mobility although it leads also to a denser (and less mobile) state. 

Evaluation of Eq. (28) is best done by nonlinear regression analysis, which yields KA, n, and /xSLn. If /j,SLn can be estimated from the apparent mobility at high ligand concentrations, then the coordination number is eas-... 

In CO2 gas, the density-normalized electron mobility /ig fe is independent of temperature (2 X 10 molecule/cm V sec [25]), although the apparent mobility steadily decreases with the pressure free electrons are trapped by neutral (C02) clusters ( = 6) with nearly collisional rates, and the electron affinity of these clusters > 0.9 eV. When extrapolated to solvent densities of (2-15) x 10 cm typical for sc CO2, these estimates suggest that the free electron mobility is ca. 1 cm /V sec and its collision-limited lifetime Xg < 30 fsec [18]. If the lifetime were this short, the electrons would negligibly contribute either to the conductivity or the product formation. However, this extrapolation is not supported by experiment [18,20]. 

By combining the apparent mobility and the electro-osmotic flow, which is responsible for the migration of the bulk electrolyte, it is possible to calculate the migration velocity or the electrophoretic mobility of charged species. Using equation (8.3), equation (8.5) can be written as ... 

The apparent mobility, xapp, of a particular species is the net speed, nnet, of the species divided by the electric field, E ... 

For quantitative analysis by electrophoresis, normalized peak areas are required. The normalized peak area is the measured peak area divided by the migration time. In chromatography, each analyte passes through the detector at the same rate, so peak area is proportional to the quantity of analyte. In electrophoresis, analytes with different apparent mobilities pass through the detector at different rates. The higher the apparent mobility, the shorter the migration time and the less time the analyte spends in the detector. To correct lor time spent in the detector, divide the peak area for each analyte by its migration time. 

The apparent mobility of P" is obtained from its migration time ... 

Electrophoretic mobility describes the response of the ion to the electric field. We subtract the electroosmotic mobility from the apparent mobility to find electrophoretic mobility ... 

The first term is the regular electrolytic term, the second the convection term. This convection term is derived with the aid of iceonv. = A F un, where u0 is the apparent mobility of the pore liquid. This latter factor is... 

Actually this is not found. In general it appears that if a membrane has a specific affinity for a definite ion, the apparent mobility is lowered. Thus a specific factor has to be introduced, which accounts for the inter action of the ions with the membrane substance. 

Applied CE Field, V/cm Migration Time, s Apparent Mobility, pm-V/s Peak Area (arbitrary units) Efficiency, Plates/m... 

The movement (migration) of a charged species under the influence of an applied field is characterized by its electrophoretic mobility, fie, which has units of cm2 sec 1 V 1. Mobility is dependent not only on the charge density of the solute (the overall valence and size of the solute molecule), but also on the dielectric constant and viscosity of the electrolyte. Mobility is also strongly dependent on temperature, increasing by approximately 2% for each Kelvin rise in temperature.2 In the presence of electroosmotic flow (Section 4.3.3), the apparent mobility is the sum of the electrophoretic mobility of the analyte, /ze, and the mobility of the electroosmotic flow, /XGO. 

The apparent mobility, /jl, may be determined, experimentally, using the equation3... 

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