Modular multiparametric analyser for automatic vessel monitoring of nutrients in sea-water.

This paper describes the characteristics of a prototype of a modular multiparametric analyser (MicroMAC FAST MP3) for automatic monitoring of sea water and analytical methods for nutrients. The MicroMAC FAST reactor is an evolution of the basic LFA (Loop Flow Analysis) reactor. It has been conceived to assay ammonium, nitrate-nitrite and orthophosphate at low concentration in sea water samples. A sample analysis is 3-4 times faster than that obtainable with a standard LFA reactor. With respect to the previous analyser a temperature control (30-52 °C) on the measurement cell has been added (NH4, PO4), while the colorimeter and the related links for transporting the sample have been moved beyond the Loop and form a hydraulic-optical set almost completely independent from the main LFA. All the steps of a wet-chemical colorimetric analysis method are carried out in an analysis cycle sequentially. This new technique allows the preparation of two products of reaction which can be introduced at intervals of 150 seconds in the measurement cell. The statistical test show that the results of automated and manual analyses agree for all the examined parameters (4 % RSD). Multiparametric online analyzer: it is possible to connect the analytical modules to a data logger with analogue and digital signals, in order to have online simultaneous analysis of the sample. A typical application is used during research at sea which vessel does not require an operator.