Observed mobility

In step 3, a multiline-fitting program was run to optimize the pK a values to minimize the sum of residual squares between calculated and observed mobilities from Eq. (17). Figure 2 shows an example of the MS Excel spreadsheet for pK a calculation. The solver function of MS Excel could be used to perform the multiline-fitting analysis. 

Figure 3 shows a typical example of the pH-mobility curve for a monobasic drug, donepezil hydrochloride. The observed mobilities at different pHs were well in agreement with the regressed values from Eq. (17). The obtained pKa value is 9.2, which is consistent with the result via the UV method (9.1). Similar results were reported for weak acids, amphoteric compounds, as well as peptides with seven ionic groups (20). 

In the absence of EOF and separation mechanism other than electrophoresis, each analyte migrates with its own velocity which, according to Equation 6.8, is proportional to the strength of the electric field applied across the capillary tube. The constant of proportionality of the observed velocity of the charged analyte is defined as the observed mobility (p bs) and can be directly calculated by the migration time and the other experimental parameters, according to the following equation ... 

The effective mobility, expressed by Equation 6.16, can be directly calculated from the observed mobility by measuring the electroosmotic mobility using a neutral marker, not interacting with the capillary wall, which moves at the velocity of the EOF. Accordingly, the effective mobility p of cations in the presence of cathodic EOF is calculated from p ts by subtracting p gf ... 

Under conditions in which the second term is negligibly small, Equation (73) becomes identical to Equation (39), the Helmholtz-Smoluchowski result. On the other hand, when the concentration and f increase, the value of f that would be associated with an observed mobility is larger than the Helmholtz-Smoluchowski equation would indicate. 

Solution The linear semilog plot means that these data follow the equation In N = b + mure/. Since we know two points from this plot, we can evaluate the constants m and b by simultaneous equations. This procedure yields b = 5.63 and m = -3.09. Combining these constants with the observed mobility allows the number of nucleotides in the unknown to be calculated by the formula In N = 5.63 + (-3.09)(0.16) = 170. ... 

Mobility is q/fl so, the greater the radius, the lower the mobility. Most molecules are not spherical, but Equation 26-9 defines an effective hydrodynamic radius of a molecule, as if it were a sphere, based on its observed mobility. 

The apparent (or observed) mobility, xapp, of an ion is the sum of the electrophoretic mobility of the ion plus the electroosmotic mobility of the solution. 

Lammerhofer and Lindner [90] explained the chiral resolution of N-derivatized amino acids by CEC. The authors explained the formation of the transient diastereomeric ion-pairs between negatively charged analyte enantiomers and a positively charged chiral selector by multiple intermolecular interactions which might be differentially adsorbed to the ODS stationary phase. Furthermore, they claimed that the enantioseparation was achieved because of different observed mobilities of the analyte enantiomers originating from different ion-pair formation rates of the enantiomers and/or differential adsorption of the diastereoisomeric ion-pairs to the ODS stationary phase [90]. 

The mechanism of separation in NCE is based on the difference in the electrophoretic mobility of the separated species. Under NCE conditions, the migration of the separated species is controlled by the sum of the intrinsic electrophoretic mobility (fxe/)) and the electroosmotic mobility (fxeo), due to the action of electroosmotic flow (EOF). The observed mobility 0bs) of the species is related to xeo and juep by the following equation ... 

Practically, velocity (v) and observed mobility (p,o/, v) of the analyte, electrophoretic mobility ( xep), and electroosmotic mobility ( eo) can be calculated by the following equations. 

The mobility model is based on the empirical fitting of the time-of-ffight data to obtain the observed mobility-field dependence [42, and references given therein]. In the mobility model the mobility p is assumed to vary with electric field F according to the formula... 

Baker [27] observed mobilization of small particles of several metal oxides on graphite at a temperature (the so-called mobility temperature) that was identical to the Tammann temperature. Thus, at least in systems exhibiting relatively weak interactions between active phase and support surface, particle mobility may be induced at this temperature. The particle migration may perhaps be described as a floating of the active phase particle on the liquid-like surface layer. 

The equation is similar to that used in chromatography [8] if the relative migration differences are inserted. These are proportional to the relative observed mobilities that include the contribution of the EOF ... 

A strength of the system is its ability to undertake anode reform, with a comfortable reaction rate, and low thermal stress at 600 °C. The ability of the MCFC to achieve 40 000 h operating life is still being demonstrated by its protagonists. Moreover, changes to the molten carbonate formulation are under consideration. Observed mobility of the molten carbonate, within the matrix conceived as fixing it, has been ascribed by the author to the surface tension gradient associated with concentration and temperature differences. 

Is the order of magnitude of your result consistent with the observed mobility If not, suggest an alternative model for electronic conductance of alkali metals in alkali metal salts. 

A heterogeneous pore structure with varying aspect ratio would increase the frequency of breakup and coalescence, which should increase the observed mobile ganglia size distribution. However, the basic flow mechanism should remain unchanged. Also the relative importance of snap-off as a breakup mechanism would be increased relative to dynamic splitting. Here too a detailed study seems desirable. 

Initially, the ability of PVK to transport charges was assumed to be related to the spatially crowded structure of PVK (7), in which the carbazole groups, because of their covalent-bonding backbone, are forced to interact with each other to the point that significant orbital overlap creates a band structure. However, the observed mobilities were low cm /V-s),... 

In glassy polymeric media, electronic transport can be phenomenologically thought of as a series of discrete steps characterized by a distribution of waiting times i /(t). When the distribution extends into the time scale of observation, the mobility itself will always appear to be time dependent. However, when the distribution does not extend into the time scale of observation, mobility can be characterized by an averaged value for most of the transit event, even though it exhibits thermalization at early times, which may be resolvable under certain experimental conditions (26, 27). Several more microscopically detailed pictures can correspond to this phenomenological description of electronic transport. 

A compilation of the observed mobility temperatures of various metal and metal oxide particles dispersed on graphite has been presented by Baker (ref. 77). This data is shown in Figure 10, where the experimentally observed temperature for the onset of mobility of 10 nm sized particles is plotted against their respective bulk melting points. It is apparent that a linear relationship exists between these two parameters which can be expre.ssed in the form ... 

An important factor in determining the morphology of the amorphous film grown through MD simulations is the observed mobility of the SiHs radical on the amorphous growth surface as the deposition proceeds (Ramalingam, 2000). The dynamics of the radical on the surface is... 

Data obtained with an apparatus of this type on particles of an oil emulsion are plotted in Fig. 9, in which the observed mobilities, in centimeters per second per volt, of the particles are ordinates and the distances from the top surface of the channel are abscissae. The results are from the measurements of Ellis,17 who first applied the method. It is evident that the measured mobilities of the particles are not constant, but change markedly with the distance of the particles from the walls of the channel. As is shown in the figure, the direction of the... 

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