title: A prototype industrial sensing system for phosphorus based on micro system technology.
abstract: Progress in the development of a miniaturised microfluidic instrument for monitoring phosphorus in natural waters and wastewater is presented. The yellow colorimetric method for phosphate analysis has been transferred to a microfluidic chip configuration This simple method employs one reagent mixed in a 1:1 ratio with a sample to produce a yellow colour absorbing strongly below 400 nm. A stopped flow approach is used which, together with the very rapid kinetics and simple reagent stream, enables a very uncomplicated microfluidic manifold design to be adopted. The working wavelength is 380 nm to coincide with the peak output of a recently developed UV-LED narrow bandwidth light source. The limit of detection for the yellow method is 0.2 ppm with a dynamic linear range from 0-50 ppm possible. The reaction time at room temperature is less than 3 min, which means that up to 20 samples per hour can be analysed.
authors.affiliation: National Centre for Sensor Research, Dublin City University, Ireland.
authors.forename: Michaela
authors.initials: M
authors.lastname: Bowden
authors.forename: Margaret
authors.initials: M
authors.lastname: Sequeira
authors.forename: Jens Peter
authors.initials: JP
authors.lastname: Krog
authors.forename: Peter
authors.initials: P
authors.lastname: Gravesen
authors.forename: Dermot
authors.initials: D
authors.lastname: Diamond