Two or Several Lines

The dispersion of sample and reagent solution in a two-line FIA system differs from a single-line system in two ways  

The dispersion coefficient Ds of the sample cannot reach a value of 1, even when a flat or a steady state is observed. 

The dispersion of reagent is not influenced by the dispersion of the sample zone, because the reagent is being added to all elements of the dispersing sample zone in the same amount. 

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- 

If original stoichiometric concentrations and pumping rates in the two-line system are equal, then equivalence is met at which means 

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