Choose your method, enter measurements, and calculate mobility in seconds today easily. See velocity, field, and model notes, then download tidy reports as files.
These examples show typical magnitudes. Replace with your experimental values.
| Scenario | Inputs | Computed mobility (m²/V·s) | Computed mobility (cm²/V·s) |
|---|---|---|---|
| Capillary observation | v = 1.2×10⁻⁴ m/s, E = 2.0×10³ V/m | 6.0×10⁻⁸ | 6.0×10⁻⁴ |
| Gel tracking | d = 35 mm, t = 180 s, E = 250 V/cm | 7.777…×10⁻⁹ | 7.777…×10⁻⁵ |
| Zeta model | ζ = -25 mV, εr = 78.5, η = 1.0 mPa·s, f = 1.5 | -2.61×10⁻⁸ | -2.61×10⁻⁴ |
Electrophoretic mobility (μe) links motion to the applied electric field, making it a core metric for separations, colloid stability, and surface chemistry. Higher absolute μe usually means faster migration at the same field, enabling shorter runs or reduced voltage demands. It also supports method comparison across instruments and sample types.
In microscopy or capillary observations, velocity is measured directly and mobility follows μe=v/E. In gels and microfluidic chips, distance and time are tracked, so v=d/t is computed first. This calculator supports both workflows with unit conversions and consistent SI outputs for reporting and teaching.
In many aqueous systems, ionic mobilities often sit near 10−8 to 10−7 m²/(V·s), while particles and macromolecules frequently appear closer to 10−9 to 10−8 m²/(V·s). Values far outside these bands can signal unit errors, heating, or electro-osmotic flow. Use them for screening before reporting.
Electric field is commonly computed as E=V/L, where L is electrode spacing. Typical laboratory fields range from about 102 to 105 V/m, depending on geometry. Increasing E boosts speed but can increase Joule heating, bubbles, or band broadening, so stable buffers help.
Mobility depends on solvent properties. Viscosity drops as temperature rises, which increases μe for a fixed zeta potential. Relative permittivity can also change with temperature and composition, affecting ε=εrε0. When comparing runs, record temperature and viscosity assumptions.
If velocity is unavailable, mobility can be estimated from zeta potential using μe=(εζf)/η. Smoluchowski (f≈1.5) is used for thin double layers at higher ionic strength, while Hückel (f≈1.0) applies for thicker double layers at low ionic strength. Henry’s model allows intermediate f.
Verify signs and units early: negative ζ should produce negative mobility under the same convention. Ensure field units match geometry; V/cm versus V/m causes 100× errors. If μe changes with E, consider electro-osmotic flow, polarization, or nonlinear effects at high fields.
Report μe in m²/(V·s) and optionally cm²/(V·s), along with field, temperature, buffer, and model choice. Showing ×10−8 m²/(V·s) helps comparison with literature tables. Use the CSV and PDF exports for traceable records and quick review during audits.
It is the proportionality between migration velocity and electric field: μe = v/E. It describes how fast a charged species moves per unit field in a given medium.
SI is m²/(V·s). Many labs also report cm²/(V·s) by multiplying by 10,000. Keep the same units across datasets to avoid hidden scaling errors.
Use E = V/L, where V is applied voltage and L is electrode spacing along the field direction. Convert L to meters if you want E in V/m.
Use it when you have ζ measurements and need an estimated mobility, or when validating trends across formulations. It assumes the Henry/Smoluchowski/Hückel framework and requires viscosity and permittivity.
With the common convention, negative mobility indicates motion opposite the electric-field direction, typically for negatively charged particles or ions. Make sure your sign convention matches your instrument’s reporting.
Field-dependent mobility can indicate heating, electro-osmotic flow, polarization, or nonlinear electrophoresis. Check buffering, temperature, and whether the measured velocity includes bulk flow.
The CSV and PDF exports mirror the displayed values and method notes. For publication, also record raw measurements, temperature, buffer composition, and any instrument corrections used.
Accurate mobility estimates help optimize separations and formulations daily.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.