New computer controlled gradient methods in flow analysis: continuous and digitalized flow titrations

By means of synchronously controlled micropumps linear concentration gradients are generated. The precisely defined gradients can be used for flow titrations and the continuous calibration of flow injection analytical methods. A versatile computer interface for the simultaneous control of up to six stepper motor drived pumps was developed. Linear gradients generated by mixing a standard stock solution with a blank stock solution have been used to calibrate an enzyme reactor combined with a fluorescence detector in reversed FIA configuration. A more sophisticated method allows the implementation of so called digital flow titrations. Continuous flow titrations can be implemented by mixing linear concentration gradients of a titration reagent with a suitable sample solution. Both titrations techniques allow absolute determinations. (orig.)SIGLEAvailable from TIB Hannover: F93B409 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman