Oscillatory control of sample dispersion in a continuous flow system

A new strategy for the instrumental control of sample dispersion in continu ous flow systems is presented. The method is based on shaking a loosely hel d straight reactor while the sample travels through the flow injection mani fold. This external disturbance yields a sample transport more similar to t he plug flow type because of the changes promoted on the flow pattern. Up t o a three-fold increase in peak height, a comparable reduction in peak widt h and a more Gaussian peak profile are observed when the signals obtained w ith the shaken reactor are compared with those obtained with the same react or but static. Improvements in the analytical performance as a function of different operational variables are shown for systems with or without a che mical reaction. Analytical implications and possible uses are discussed sin ce this strategy allows the control of dispersion by simply selecting the f requency and amplitude of oscillation.