Electrophoretic mobility defined

The velocity of particle migration, v, across the field is a function of the surface charge or zeta potential and is observed visually by means of an ultramicroscope equipped with a calibrated eyepiece and a scale. The movement is measured by timing the individual particles over a certain distance, and the results of approximately 10-15 timing measurements are then averaged. From the measured particle velocity, the electrophoretic mobility (defined as v/E, where E is the potential gradient) can be calculated. 

What is the mobility of a particle How is electrophoretic mobility defined ... 

The electrophoretic mobility defined in Equation 7.86 follows from Equation 7.89 as... 

Electrophoretic Mobility The velocity with which a solute moves in response to the applied electric field is called its electrophoretic velocity, Vepi it is defined as... 

Electrokinetic (also called electromigration) injection is performed by placing the inlet of the capillary and an electrode in the sample vial. Following this a voltage is applied during a defined period of time. The sample constituents are actively carried into the capillary, and when present, the EOF also passively carries them into the capillary. For this reason, neutral compounds are also injected. The active migration is due to the effective electrophoretic mobilities of the constituents. The amount (B), in units of concentration injected into the capillary is expressed by [2,38]... 

A particle with a net charge moves under the influence of an electric held toward an oppositely charged electrode. This phenomenon, defined as electrophoresis, is the basis for various electrophoretic methods in biochemistry research. Separation of particles via electrophoresis is achieved through the difference in their migration distances, which is dependent upon their electrophoretic mobility. 

The electrophoretic mobility p of a polyelectrolyte chain in an infinitely dilute solution containing an added salt at concentration c under a constant external electric field E, as defined through... 

In this section we consider the motion of a uniformly charged flexible polyelectrolyte in an infinitely dilute solution under an externally imposed uniform electric field E. The objective is to calculate the electrophoretic mobility p defined by... 

According to their electrophoretic mobility in supporting media, e.g., paper, agarose, or cellulose acetate, serum lipoproteins can be defined as pre-)8, j8-, and ai-lipoproteins, grossly corresponding to VLDL, LDL, and... 

The apparent electrophoretic mobility /iapp is defined by an equation analogous to (8.1) or (8.2) such that ... 

The electrophoretic mobility, tE is defined as the electrophoretic velocity divided by the electric field gradient at the location where the velocity was measured ... 

Increased voltage (and the associated gain in electrical field strength E) increases ion migration velocity U and thus separation speed (providing 0 does not increase too severely as a side effect). For many purposes, it is useful to have a convenient parameter to characterize migration velocities independent of E. The electrophoretic mobility p fulfills this role it is defined by... 

One of the main material-related parameters will be electrophoretic mobility, p. It is defined as the velocity, v, of the particles in relation to the electrical field strength, E. 

The electrophoretic mobility of the molecule fi is defined as the steady-state velocity per unit field, or... 

The electrophoretic mobility (p) is defined as the velocity per unit field strength ... 

The size and charge analysis was done using a Coulter DELSA 440SX (Coulter Beckman Corp., Miami, FL). This particular instrument measured the size distribution on the basis of photon correlation spectrometry (PCS) and was limited to particle diameters between 0.02 pm and 3 pm. Measurements were taken at four different angles simultaneously with 256-channel resolution each. Comparison of the spectra allowed for the detection of very small particles. The zeta potential was assessed on the basis of electrophoretic mobility (laser Doppler anemometry, LDA). This was defined as the particle velocity per unit of applied electrical field, with units usually given as pm s 1/V cm-1, while zeta potential is defined as the electrical potential between the bulk solution and the... 

El-FFF uses an electrical field E across the channel as the driving force for the particle separation. As the drift velocity U of a macromolecule with electrophoretic mobility pe is defined by ... 

When an electrical field is applied to a suspension of charged particles, the particles migrate toward the electrode of opposite sign, reaching a terminal velocity in a matter of microseconds. The electrophoretic mobility (EM), u ( J.m cm s-1 V-1), for a particle is defined as ... 

The electrophoretic mobility of spherical soft particles in a concentrated suspension is defined by = UIE. It must be mentioned here that the electrophoretic mobility fx in this chapter is defined with respect to the externally applied electric field E so that the boundary condition (22.8) has been employed following Levine and Neale [5]. There is another way of defining the electrophoretic mobility in the concentrated case, where the mobility /i is defined as /i = U/ E), (E) being the magnitude of the average electric field (E) within the suspension [8, 19-21]. It follows from the continuity condition of electric current that K E) = K°°E, where K and K°° are, respectively, the electric conductivity of the suspension and that of the electrolyte solution in the absence of the particles. Thus, jx and ix are related to each other by = K /K°°. For the dilute case, there is no difference between jx and jx. ... 

Consider a spherical soft particle moving with a velocity Uexp(—icot) in a liquid containing a general electrolyte in an applied oscillating electric field E exp(—icot), where co is the angular frequency (2n times frequency) and t is time (Fig. 25.1). The dynamic electrophoretic mobility /i(co), which is a function of co, of the particle is defined by... 

Samples are applied to the capillary by injection, but since the capillary volumes are so small (1 p.1 for a 50 pm 50 cm capillary) the sample volumes must be kept to a few nl if the resolution is not to be affected. Two modes of injections are used hydrodynamic and electrokinetic. In hydrodynamic injection, the sample vessel is connected to the upper end of the capillary, and a small quantity is introduced into the capillary either by applying positive pressure to the sample vessel, or a vacuum to the detector side. In electrokinetic injection, a low-voltage is applied for a short period while the capillary is linked to the sample vessel so that a defined quantity of sample is introduced into the capillary by electrophoretic or electroendoosmotic migration. In this case, there is a form of pre-separation, since particles with lower electrophoretic mobilities do not progress as far into the capillary as those with higher ones. 

In sec. 1.6.6a the mobility of individual Ions was discussed. There, the mobility was Introduced as the scalar ratio of the vectors velocity and field strength. This definition also applies to the electrophoretic mobility u, defined through... 

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