Reaction detectors solid phase reagents

FIGURE 2.34 Experimental setup used for the two modes of continuous ultrasound-assisted leaching and the possibilities of their coupling to other steps of the anal)dical process. One, two or three steps can he used in a single method. Abbreviations used are LC, leaching carrier PP, peristaltic pump UP, ultrasonic probe EC, extraction chamber WB, water bath W, waste SV, selection valve EX, extract E, eluent IV, injection valve SPC, solid-phase column DR, derivatization reagent RC, reaction coil and D, detector. (Reprinted from Luque-Garcia, J. L. and Luque de Castro, M. D., Trends Anal. Chem., 22, 41-47, 2003. With permission from Elsevier.)... 

The hardware of an automated solid-phase synthesizer consists of all the electromechanical components of the system (reaction vessel, tubing, valves, pumps, detectors, power supplies, circuit boards, sensors, etc.). It is imperative that all these components are reliable and can operate without failure for many synthesis cycles before repair or replacement. Before using any component in an automated system, it should undergo compatibility and lifetime testing with the reagents that would be in contact during the synthesis. 

However, some elements of an automated solid-phase instrument do experience more accelerated degradation. These items should be easily accessible to the user and replaced at appropriate intervals. Examples of some of these disposable elements are O-rings for sealing reagent bottles, filter frits for the reagents and reaction vessel, and the detector lamp. 

In the case of chromatographic or electrophoretic methods the derivatization reaction can take place before the separation (precolumn derivatizations) or between the column/capillary and the detector (postcolumn derivatizations). The arrangement of precolumn derivatizations can be offline (reaction separated from the chromatographic/electrophoretic procedure in time and space) or online (precolumn reactor before the injector). In the case of postcolumn derivatization, only online arrangement can exist the reactor should be inserted between the column/capillary and the detector. The derivatization in the reactors takes place usually in the solution phase, but solid-phase reactors where the reagent is immobilized on the surface of a solid support... 

MSFIA exploiting solid-phase extraction for the determination of the total phenolic index. Detector spectrophotometer HC holding coil IV injection valve R reagent RC reaction coil V solenoid valve. 

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