Evolution of the commutation concept associated with the development of flow analysis

Evolution of the commutation concept has lead to the proposal and development of different generations of flow analyzers. Since the inception of the air-segmented flow systems till the availability of modern flow injection, sequential-injection and other flow-based analytical systems, a noteworthy improvement of the commutating devices has been noted.

Multi-functional manifold is described as a polyvalent approach for methodology implementation in a flow analyzer. It permits the investigation of mixing conditions under different flow patterns (unsegmented, segmented, monosegmented) with optional exploitation of the stopped-flow approach. For this purpose, spectrophotometric or turbidimetric measurements eventually affected by Schlieren noise were considered. Potentialities and limitations of the manifold are discussed in relation with methods based on relatively fast or slow chemical reactions. As applications, phosphate and chloride determinations in plant digests and natural waters were selected.

The manifold is characterized by high versatility and may work in connection with different flow configurations. Development will certainly lead to simple, versatile and miniaturized analyzers, able to run samples in a personalized fashion. In addition, random reagent selection, full automation, expansion of the analytical application range and increasing potentialities of the already existing methodologies are devised.