The concept of zeta potential was recognized more than 100 years ago, but early instruments were fragile and custom-made. About 50 years ago, we pioneered the development of a simple, reliable instrument to measure electrophoretic mobility and zeta potential. Our Zeta-Meter 4.0 continues this tradition but with improvements that make the determination even more convenient. Our instruments are reasonably priced and feature low maintenance costs. In addition, careful quality control has enabled us to maintain an excellent reliability record. If your problem involves electrokinetics, then we probably know something about it. If we don`t make exactly what you need, then we will recommend a reliable company that does.
Understanding zeta potential can help you to understand and control colloidal suspensions. Examples include complex biological systems such as blood, and functional ones like paint. Water, milk, wine, clay, inks, dyes, paper, and pharmaceuticals are good examples of useful colloidal systems. In many cases, the performance of a suspension can be improved by understanding the effects of colloidal behavior on such properties as viscosity, settling, and effective particle size.
Each colloid carries a 'like' electrical charge which produces a force of mutual electrostatic repulsion between adjacent particles. If the charge is high enough, the colloids will remain discrete, dispersed, and in suspension. Reducing or eliminating the charge has the opposite effect - the colloids will steadily agglomerate and settle out of suspension or form an interconnected matrix.
We can often tailor the characteristics of a suspension by understanding how individual colloids interact with one another. At times we may want to maximize the repulsive forces between them in order to keep each particle discrete and prevent them from gathering into larger, faster settling agglomerates. Examples include pharmaceuticals and pastes. Sometimes we have the opposite goal and want to separate the colloids from the liquid. Removing the repulsive forces allows them to form large flocs that settle fast and filter easily. Viscosity is another property that can be modified by varying the balance between repulsion and attraction.
Each charged particle is surrounded by a diffuse layer of neutralizing ions. This causes an electrical potential on the order of millivolts to develop across the diffuse layer between the colloid and the bulk of the liquid. The magnitude of this potential is approximately proportional to the surface charge on the colloid, and it is called the zeta potential. As a result, zeta potential an important measure of the electrokinetic forces involved.
Our Zeta-Meter System 4.0 measures electrophoretic mobility and zeta potential. The basic instrument is for aqueous suspending liquids but accessories are available for working with organic suspending liquids.
Zeta potential measurements are made using a technique called microelectrophoresis. The measurement is very direct. First, your sample is placed in a viewing chamber called an electrophoresis cell. Then an electric field is activated. This causes the colloids to move with a velocity that is proportional to their zeta potential, and in a direction that indicates whether their charge is positive or negative.
Colloids are comfortably observed and tracked using video optics or a high quality stereo microscope. Once your sample is in the cell, you get your first results in a matter of seconds, and complete results in minutes.
Just fill the cell with your sample, insert the electrodes and connect them to the Zeta-Meter 4.0 unit. It determines the specific conductance of your sample and helps select the appropriate voltage. Energize the electrodes and watch the colloids as they move across a grid in your microscope or video display.
Track one by simply pressing a keypad button and holding it down while your colloid moves across the grid. When you release the button, your colloid’s zeta potential (or electrophoretic mobility) is instantly displayed.
The data display shows you: how many colloids you have tracked, their average zeta potential (or electrophoretic mobility) and the statistical standard deviation of your values. In addition, temperature and average specific conductance are also displayed. You can also review your data in detail at any time by using the keypad to step through each individual tracking value.
We supply software that lets you feed your data directly into the serial port of a personal computer. Our software imports your data into a database that lets you store, search, graph, print and review your data.
If you buy an instrument from us, you're entitled to unlimited technical support. Call, fax or e-mail us for help. We will do everything possible to solve your problems. All questions and suggestions are welcome; all advice and support is free.
You can rent a Zeta-Meter to be sure it meets your needs, and part of your rental cost can be applied to your purchase. We can also run a preliminary test on one of your samples, but it's always better to try it yourself.
Two Year Warranty
All of our instruments are covered by a 2-year limited warranty. Actually, it is very rare for our instruments to have any problems at all, but it's nice to know that you are protected.
Free 'Loaner' Instrument
If your Zeta-Meter does need servicing and you just can't do without it, don't worry-- we'll send you one at no charge. Just pay the freight and insurance and it's yours for as long as we have your system here for repair. In fact, if your unit is under warranty then we will ship the replacement to you absolutely free. We can't ship you a substitute unit if you are outside the USA; instead, we'll ship you easy-to-install replacement parts by express mail or courier service.
Support for the Zeta-Meter System 3.0 & 3.0+
We provide ongoing support for the previous generations of our instrument, and can repair or refurbish them. We can also upgrade the microscope version of these instruments to direct video imaging. If you have one of our Zeta-Meter System 3.0 or 3.0+ units then please contact us for a free CD with the latest operating instructions along with updated software for the Zeta-Meter System 3.0+.
Really Old Instruments
Yes - we still support the early versions of our Zeta-Meter. Some date all the way back to the 1960's.