Kinetic Parameters of Continuous Flow Analysis

Abstract

Unlike systems of batch analysis, continuous flow systems possess kinetic parameters. Associated with the steady state are such measurements as noise level and drift. This study reports on kinetic parameters associated with the transient state between the steady states including time required to change from base-line steady state to sample steady state and vice versa, characteristics of this change, time interval between samples, proportionality of sampling and washing time, fraction of steady state reached in any given sampling time, and interaction between samples. The transition between steady states has been found to obey first order kinetics to a good first approximation. This observation enables correlation of all of the above listed properties in quantitative fashion using new characteristic constants for continuous flow-the half-wash time (W1/2) and the lag phase time (L). These parameters, well known in other contexts such as radioactivity, can be employed as "figures of merit" for any continuous flow system or component, can be utilized to calculate performance characteristics, and are useful in evaluating and optimizing over-all performance.

Dispersion in segmented flow through glass tubing in continuous-flow analysis: the ideal model

“…Bolus Flow. An understanding of mixing in segmented flow must begin with the characteristic bolus flow pattern that is observed within moving segments (2,4,5). Figure 1 shows a schematic of this flow pattern, which is readily observable by adding dye at different points within the moving liquid segment.…”

“…While an exact expression for such longitudinal dispersion was developed 20 years ago by Golay for unsegmented flowing streams (3), no comparable treatment has been reported for dispersion in segmented liquid streams. Early attempts at describing dispersion in segmented-flow systems (e.g., [4][5][6][7][8][9] were limited to empirical relationships for the shape of sample curves following CF analysis. These equations were useful in correcting for sample carryover, but offered limited insight into the dispersion process.…”

A generalized system for automation of enzyme assays

“…Stock reagent: reagent used to prepare line reagent by suiitable dilution. Half,wash time: time taken to change concentration at a given time to a concentration half-way between it and the final steady-state concentration (see Thiers, Cole & Kirsch, 1967).…”

“…1at various flow rates. The sample probe was placed in a marker solution for various times and the half-wash time determined from plots of log(100 -% steady state) against time (seeThiers et al 1967;Roodyn, 1970). Calibration conditions were as inFig.…”

Electronic bubble gate for colorimetric, air-segmented, continuous flow analyzers

“…This result is contrary to predictions of Snyder's model (1) under these experimental conditions (see Table I). However, Snyder's model does not consider contributions to the total observed dispersion of the sample slug caused by mixing effects in unsegmented zones of the CF system; these impose an exponential (12,13) Gaussian deformation on the concentration vs. time profile of the sample slug. On the mCF system, for example, the linear distance from the tip of the sample probe, through the pump, and into the air injector fitting is about 30 cm.…”