Accuracy of electrophoretic mobility measurements by applying a slow flow

A method for improving sensitivity and accuracy of electrophoretic mobility measurements, comprising:

• applying a slow flow to continuously remove a sample from a measurement cell during a measurement operation involving an application of electrical current;
• replacing the removed sample with fresh sample during the measurement operation;
• applying higher electric fields than would be possible without the slow flow;
• and
• extending measurement times beyond what would be achievable without the slow flow;
• wherein the continuous removal and replacement of sample enables the application of higher fields and longer measurement times, thereby improving sensitivity and accuracy of the measurement operation.

A system for electrophoretic mobility measurement, comprising:

• a sample cell configured to contain a sample having particles;
• a flow system configured to flow the sample through the sample cell at a non-zero flow rate;
• and
• electrodes configured to apply an electric field to the sample in the sample cell;
• a light scattering detector configured to measure electrophoretic mobility of the particles while the sample flows through the sample cell and the electric field is applied, wherein the flow system is configured to continuously remove electrolysis products and degraded sample particles from a measurement region and replace them with fresh sample.