High Resolution Zeta Potential Measurements: Analysis of Multi-component Mixtures

Abstract

ABSTRACT Microelectrophoresis is an important technique for characterizing the surface charge and stability of colloidal dispersions. Zeta potential has been calculated from electrophoretic mobility measurements using capillary cell electrophoresis for more than 50 years. This particular new method for obtaining electrophoretic mobility and zeta potential results improves the resolution compared with previous methods, provides accurate mean mobility and mobility distributions in a single measurement, avoids making multiple measurements at different locations through the capillary cell and eliminates the requirement for measurement at the stationary layer of a capillary cell altogether. M3 is an acronym for “Mixed Mode Measurement”. This new measurement method is a combination of measurements that improve the resolution of mean electrophoretic mobility measurements and provide mobility distribution results that will be described herein. The combination of measurements includes a fast field reversal measurement to provide the accuracy and stability of the result, and a slow field reversal measurement to improve the resolution of the result by providing accurate mean mobilities and mobility distributions. The combination of these measurements takes less than 1 min to complete. Examples of high-resolution mean electrophoretic mobility latex studies and latex mixtures resulting in multimode zeta potential distributions are illustrated. Zeta potential distribution differences on the order of 10 mV have been obtained on latex mixtures with this new technique.