Some Miniaturized Impedance Sensors, Their Application to Flow Measurements and Hyphenation with High-Performance Separations
Abstract
The present state of the theory of high-frequency impedance sensors (now mostly called contactless conductivity sensors), the principal approaches to designing impedance flow-through cells and their operational parameters are critically discussed. The most important problems to be solved in coupling these devices with high-performance separations in liquid phases are further elaborated.
Examples are given of cell designs for continuous flow and flow-injection analyses, and of detection systems for miniaturized liquid chromatography and capillary electrophoresis. Typical practical analyses, mostly from the area of biology and medicine, illustrate this discussion, indicate the application range of these measurements and suggest some directions for future development.