A generic FIA system for determination of enzyme activities : Assay of cellulase

The concept of a generic FIA system is described that allows multi-points assays of enzyme activities, that require a coupled chemical derivation reaction for detection. The enzymatic degradation procedure and the ensuing chemical indicator reaction are completely separated, which inherently allows each of these processes to be individually optimized with respect to operational parameters such as heating, cooling or possibly stopped flow manipulations. The applicability of the approach is demonstrated for the determination of the activity of cellulase using spectrophotometric detection via a couple chromogenic indicator reaction.     

A prototype industrial sensing system for phosphorus based on micro system technology

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.