Applications of continuous segmented analysers

Continuous air-segmented flow analysers have lost the excellent place they had in the automation of sample processing, particularly in the field of clinical chemistry. The advantages of their batch counterparts have consigned them to relative oblivion. Despite Snyder s predictions in 1980 [28], the advent of cheaper, faster, technically simpler and more versatile alternatives to continuous analysers (e.g. FIA) was a severe blow to the earlier analysers. However, It is worth noting the remarkable degree of technical perfection reached 

The potential of these analysers is clearly revealed In Furman s book on the topic [10], the literature on which frequently refers to technical reports published by the manufacturers themselves. 

The applications of automatic continuous segmented analysers can aiso be classified according to the type of detection system involved. Thus, 70-75 of all the methodologies described on this topic used molecular UV absorption spectroscopy (spectrophotometry, photometry), followed by ISE potentiometry (10-15 ) and, much less often, nephelometry, fluorimetry, etc. The applications described below were mostly developed with the aid of Technicon technology and are classified according to this criterion —other applications to specific problems related to laboratory processes are described in the corresponding chapters. 

The first three determinations described here use the detection technique most frequently employed with continuous segmented systems, namely spectrophotometry, and feature interesting differences in the configurations involved. 

The manifold depicted in Fig. 5.13 Is used for the determination of chloride Ion In sea and tap water [31]. It uses a dialyser to remove interferents. The reagent Is a mixture of mercury(II) thiocyanate and Iron(III) nitrate, which, in the presence of the analyte, loses the red coloration of the Fe(IIl)-SCN- complex as a result of the formation of the stabler Hg(II)-CI- 

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