ELECTROOSMOSIS - A RELIABLE FLUID PROPULSION SYSTEM FOR FLOW-INJECTION ANALYSIS

An electroosmosis based fluid propulsion system is described. The electroosmotic pump, operating in a high electric field, is isolated from other components by a grounding joint that is electrically conductive and permits the pumped fluid to be hydrodynamically coupled to contents downstream without leakage. The pump was used in single- and double-line flow injection analysis (FIA) systems. The determinations of chloride and iron(III) are discussed as representative examples. The experimental results showed excellent reproducibilities (relative standard deviation 0.4-0.8%), reflecting the stability and the reliability of the pump, The system can also be operated in a hybrid manner, On-line preconcentration (based on the electrostacking effect as used in capillary zone electrophoresis) is performed first, followed by FIA. The electrosmotically pumped fluid can be hydrostatically coupled to propel other fluids that are electrically too conductive or too resistive to be directly pumped.