Electrophoresis
When an electric field is applied across an electrolyte, charged particles suspended
in the electrolyte are attracted towards the electrode of opposite charge. Viscous
forces acting on the particles tend to oppose this movement. When equilibrium is
reached between these two opposing forces, the particles move with constant
velocity
.
The
velocity
of the particle is dependent on the following factors :
.
Strength of electric field or voltage gradient.
.
The Dielectric constant of the medium.
.
The Viscosity of the medium.
.
The Zeta potential.
The
velocity
of a particle in an electric field is commonly referred to as its
Electrophoretic mobility
.
With this knowledge we can obtain the zeta potential of the particle by application
of the
Henry equation
.
The
Henry equation
is :
.
z
: Zeta potential.
.
U
E
: Electrophoretic mobility.
.
e
: Dielectric constant.
.
h
: Viscosity.
.
ƒ(Ka)
:
Henrys
function.
Two values are generally used as approximations for the
f
(Ka)
determina-
tion - either
1.5
or
1.0
.
Electrophoretic determinations of zeta potential are most commonly made
in aqueous media and moderate electrolyte concentration.
f
(Ka)
in this
case is
1.5
, and is referred to as the
Smoluchowski
approximation.
Therefore calculation of zeta potential from the mobility is straightforward
for systems that fit the Smoluchowski model, i.e. particles larger than about
0.2 microns dispersed in electrolytes containing more that 10
-3
molar salt.
The
Smoluchowski
approximation is used for the folded capillary cell and
the universal dip cell when used with aqueous samples.
C H A P T E R 1 5
Z e t a s i z e r
N a n o
S e r i e s
P a g e 1 5 . 4
M
A
N
0
3
1
7
Summary of Contents for Zetasizer Nano Series
Page 7: ...Part 1 Operators guide Part 1 Operators guide...
Page 8: ......
Page 9: ...Introduction to this manual Introduction to this manual C H A P T E R 1...
Page 10: ......
Page 16: ...C H A P T E R 1 Z e t a s i z e r N a n o S e r i e s Page 1 6 M A N 0 3 1 7...
Page 17: ...What is the Zetasizer Nano What is the Zetasizer Nano C H A P T E R 2...
Page 18: ......
Page 26: ...C H A P T E R 2 Z e t a s i z e r N a n o S e r i e s Page 2 8 M A N 0 3 1 7...
Page 27: ...How does the Zetasizer Nano work How does the Zetasizer Nano work C H A P T E R 3...
Page 28: ......
Page 51: ...Making measurements A tutorial Making measurements A tutorial C H A P T E R 4...
Page 52: ......
Page 78: ......
Page 90: ...C H A P T E R 5 Z e t a s i z e r N a n o S e r i e s Page 5 12 M A N 0 3 1 7...
Page 91: ...Sample Preparation Sample Preparation C H A P T E R 6...
Page 92: ......
Page 100: ...C H A P T E R 6 Z e t a s i z e r N a n o S e r i e s Page 6 8 M A N 0 3 1 7...
Page 101: ...Maintenance Maintenance C H A P T E R 7...
Page 102: ......
Page 107: ...Part 2 Supervisors guide Part 2 Supervisors guide...
Page 108: ......
Page 109: ...Security Security C H A P T E R 8...
Page 110: ......
Page 118: ...C H A P T E R 8 Z e t a s i z e r N a n o S e r i e s Page 8 8 M A N 0 3 1 7...
Page 119: ...Using SOPs Using SOPs C H A P T E R 9...
Page 120: ......
Page 152: ......
Page 161: ...Exporting results Exporting results C H A P T E R 1 1...
Page 162: ......
Page 168: ...C H A P T E R 1 1 Z e t a s i z e r N a n o S e r i e s Page 11 6 M A N 0 3 1 7...
Page 169: ...Creating custom reports Creating custom reports C H A P T E R 1 2...
Page 170: ......
Page 183: ...Size theory Size theory C H A P T E R 1 3...
Page 184: ......
Page 193: ...Molecular Weight theory Molecular Weight theory C H A P T E R 1 4...
Page 194: ......
Page 200: ...C H A P T E R 1 4 Z e t a s i z e r N a n o S e r i e s Page 14 6 M A N 0 3 1 7...
Page 201: ...Zeta Potential theory Zeta Potential theory C H A P T E R 1 5...
Page 202: ......
Page 215: ...Part 3 Appendices Part 3 Appendices...
Page 216: ......
Page 217: ...Health and Safety Health and Safety A P P E N D I X A...
Page 218: ......
Page 223: ...Specification Specification A P P E N D I X B...
Page 224: ......
Page 227: ...Site requirements f r o m M A N 0 3 1 7 I s s u e 1 0 Site requirements A P P E N D I X C...
Page 237: ...Installation Installation A P P E N D I X E...
Page 238: ......
Page 241: ...Regulatory Statements Regulatory Statements A P P E N D I X F...
Page 242: ......
Page 246: ...A P P E N D I X F Z e t a s i z e r N a n o S e r i e s Page F 4 M A N 0 3 1 7...
Page 247: ...Index Index...
Page 248: ......