Microparticles for standardization of electrophoretic devices and process control

An appreciation of the importance of particle surface charge as a determinant of the behavior of particle suspensions has stimulated interest in electrophoretic analyses of small particles. Currently available analytical particle electrophoresis equipment provide increasingly powerful techniques for probing the surface charge of small particles so that the potential of the application of the method may be realized in basic and applied research as well as in process development and control in manufacturing environments. Two recurrent issues in the application of the methods are the qualification of the instrument operation and the consistency of the reagents employed. Here we describe strategies for addressing these problems through the use of uniform detergent free, charge-stabilized polymer microspheres first as control particles for monitoring satisfactory instrument operation and secondly as sensitive "reporter" probes for detection of trace contaminants in the suspending media used for electrophoretic analysis.