Speeds, of ions

Relative speed of ions. The motion of cations and anions in opposite directions through the solution between the electrodes is analogous to the drawing together of two boats by means of a rope between them. 

The Moving Boundary Method.—The moving boundary method for measuring transference numbers involves a modification and improvement of the idea employed by Lodge and by Whetham (cf. p. 60) for the study of the speeds of ions. On account of its relative simplicity and the accuracy of which it is capable, the method has been used in recent years for precision measurements. ... 

To increase the speed of ion flow, a relatively large electric field is used (greater than, for example, that used in the CPC method, described below). Under these conditions, we can neglect the diffusion and convection components of current compared to the migration component. Then the density of current j + due to cations with number n, is ... 

Speed of plane kinematic wave Speed of kinematic shock moving up from container bottom True electrophoretic velocity in electrophoresis cell Speed with which a point with ionic fraction Xg in solution moves Electroosmotic velocity in electrophoresis cell Speed of ion exchange zone front Liquid velocity in electrophoresis cell Maximum fluid velocity at center of circular or straight channel with fully developed velocity profile, Eq. (4.2.14) Velocity at free surface of... 

The electromigration velocity in Equation 2.13 is the speed of ion movement in the pore water caused by an electric field in infinitely dilute solutions. In the pore fluids with finite ion concentrations, which more closely resemble the electrochemical systems of contaminated clays, influence of the interionic attraction should be considered. Generalized ion mobility that account for the possibility of interactions... 

The timescale (Jr) of adjusting to the variation of E is controlled by two phenomena limiting the speed of ion rotation— the inertia and viscous friction " with characteristic times of tjn and tyis, respectively. One may approximate... 

By Equation 3.48, the speed of ion elimination from the gap is proportional to both K and AEp . As the absolute mobilities of precursor and product ions generally differ, their v values are unequal despite fixed... 

One shortcoming of gas phase ion mobility spectrometry is its inability to maintain high resolving power at small scale. The separation efficiency of time-of-flight ion mobility spectrometry is limited by the low-field requirement, the speed of ion shutter gate relative to the drift time of analyte ion, and the space charge effect. 

The simplest form of IMS is TOFIMS, where the speeds of ion travel through the drift tube are registered as the time of arrival at the detector from the fastest to the slowest. In simple systems this is... 

Dynamic phenomena have been investigated with MS for half a century now (e.g., [34-37]). Ions cannot move as fast as photons while mass spectrometers typically operate in the microsecond regime. Therefore, MS cannot equalize temporal resolutions achieved with some optical techniques (which are currently limited by the speed of detection systems rather than the speed of photons). Temporal resolution is a critical limitation when it comes to identifying reaction intermediates and measuring reaction kinetics by MS [38]. As it will be evident later on, the speed of MS is currently limited by the speed of sample processing rather than the speed of ions. 

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