Eight-channel Sixteen-port Multifunctional Valve

3 Eight-channel Sixteen-port Multifunctional Valve 

A design which has shown great versatility in FI separation systems, and which will be extensively referred to in the examples presented in later chapters is the eight-channel multi-functional valve first reported by Fang et al. in 1984. This valve was used as a principle component in a dual column on-line ion-exchange preconcentration system for flame AAS [5]. Commercial versions with such a design are available from Chinese (Zhaofa, Syntone), Swedish (Tecator), and Japanese (Hitachi) FI instrument manufacturers. 

(aMb) Applications of the 8-channel multifiiiictiona] valve. A, volume-based sample injection. V. multifunctional valve X. blocked channel S, sample C, carrier LS, sample loop W. waste line D. detector. 

A few of the many functions which could be performed by this valve are shown in Fig. 2.S, and more will be presented in applications in the later chapters. Not all the channels are required in every application the unused channels are blocked using a blind conneaor if necessary, or simply left open, if not. 

samples E, eluent R, reagent B, buffer C, carrier LR, sample and reagent loops W, W, Wl. Wl, W2, waste lines note that W and W, W1 and wr are the same waste lines D. detector. 

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