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Single-line system

The Schlieren effect tends to be pronounced. It should be noted that undesirable concentration gradients leading to the appearance of the Schlieren effect (see also 4.2) are dependent on differences in the original composition of the sample and carrier solutions and that the effects are more pronounced in single-line systems. [Pg.81]

In this configuration, the sample is inserted into a chemically inert carrier stream and the reagents are added by confluence (Fig. 3.10, lower). Although a dilution-like effect occurs at the confluence sites, better sensitivity in relation to single-line systems is usually attained. Confluence systems are therefore potentially high sensitivity systems [114]. [Pg.82]

The dispersion process can be better understood by considering a model single line system into which a solution of dye A is inserted into an inert carrier stream. At the time of insertion (time zero), the plug of this solution is ideally a perfect cylinder and the associated concentration/ time function is hypothetical and rectangular in shape (Fig. 5.9a). [Pg.159]

Determination of dispersion Single-line system. Also determine the dispersion by clamping the reagent tube to convert to a single-line system remove the tube from the pump. Determine the dispersion as above-and compare with that of the two-line system. [Pg.789]

Figure 2.13. Mutual dispersion profiles of sample (5) and reagent (/ ) in a single-line system. (a) Single-line manifold where sample of original concentration C is injected into a carrier stream of original concentration C% at time to. The detector senses the dispersed zone within which the mutual concentrations of sample and reagent are Cr and Cs (if no chemical reaction has taken place), b) Mutual concentration gradients of Cr and C5. Figure 2.13. Mutual dispersion profiles of sample (5) and reagent (/ ) in a single-line system. (a) Single-line manifold where sample of original concentration C is injected into a carrier stream of original concentration C% at time to. The detector senses the dispersed zone within which the mutual concentrations of sample and reagent are Cr and Cs (if no chemical reaction has taken place), b) Mutual concentration gradients of Cr and C5.
To conclude, the concentration gradients of sample and reagent in a single-line system are mirror images of each other, and if the D value approaches 1, a lack of reagent in the core of the sample zone will occur. This is why two-line manifolds have been designed [3, 10, 20, 153], they avoid the formation of double peaks. It will be shown, however, that double peaks may be exploited in several novel ways as a source of additional information on analyte composition (cf. Sections 2.4.4 and 2.5). [Pg.42]

The dispersion of sample and reagent solution in a two-line FIA system differs from a single-line system in two ways ... [Pg.42]

Thus, compared to a single-line system it is easier to maintain an excess of reagent throughout the entire sample zone, even when Ds is close to steady state. This is because cannot be lower than 2, and, there-... [Pg.43]

According to this equation, the detection limit for a single-line system (cf. Fig. 2.13) occurs when the equivalence condition is met... [Pg.57]

Technically, FIA titrations can be performed either in a single-line system, as discussed previously, or in a two-line system (cfr. Fig. 2.14 and Section 4.9.). For a two-line system, where titrant R is confluenced to a sample zone dispersed in an inert carrier stream. [Pg.58]

In Fig. 4.68 is shown a microconduit incorporating two potentiometric pH electrodes and a common reference electrode, the introduction of sample solution being executed by means of an exteriorly placed injection port. The measurement of pH requires a system with limited dispersion coefficient, and no chemical reaction is needed in the flow channel. Consequently, a short residence time was chosen, and the two pH-sensitive PVC-based membrane electrodes, containing as electroactive material tri- -dodecylamine [778], were placed in a single-line system and very close to the injection position (cf. Fig. 4.3), the Ag/AgCl wire reference electrode being situated in a side channel and connected to the main channel downstream from the indicator electrodes. The manifold construction is such that the reference solution and thus the liquid junction are renewed... [Pg.249]


See other pages where Single-line system is mentioned: [Pg.499]    [Pg.49]    [Pg.72]    [Pg.82]    [Pg.667]    [Pg.40]    [Pg.44]    [Pg.62]    [Pg.78]    [Pg.153]    [Pg.153]    [Pg.264]    [Pg.332]    [Pg.81]   
See also in sourсe #XX -- [ Pg.26 , Pg.40 , Pg.129 , Pg.140 , Pg.147 ]




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