Predicted depth-averaged, unreacted sample fraction MR versus the Lagrangian sample residence time t for varied reaction half-lives t1/2 and fixed sample Qsa and sheath Qsh flow rates. The reaction studied involved ascorbic acid H2Asc and ferricyanide reactants and dehydroascorbic acid Asc and ferrocyanide products. The shaded area near the lines shows the range of possible MR given variations in sample and sheath species diffusivities of 10%. The second-order decay rate for these simulations was estimated as k = . Data are for initial concentrations of = 40 mM and [H2Asc]0 = 200 mM.