The controlling of the flow in the microchannels by electroosmosis and thus simply switching the voltage makes this technique suitable for miniaturisation. The optimisation of a micro flow injection system for the determination of phosphates in water was discussed. The essential factors like concentration of acid, reagent and current are optimised with the simplex method. The detection limit proved to be around 1ppm PO4. A portable system for further miniaturisation with the aim of field experiments was developed. To enhance the reproducibility the injection plug is compressed by an additional voltage. The sample is hence diluted with additional reagent and this phenomenon is used as calibration with controlled dilution with the advantage of having only one standard concentration.
|Effective start/end date||1/01/95 → 31/01/14|