RK-Spectro Technical Note 49: Determination of minimum washing volume for the microcuvette (mFC-08)

Introduction

In a stopped-flow experiment, it is necessary to completely wash the flow path from the last mixer to the observation point of the cuvette, or in other words, to get rid of the solution from the previous shot. If the volume pushed into the cuvette is too small, a stationary state inside the cuvette may not be reached and part of the kinetics lost. This volume is dependent on the nature of the reactants and the geometry of the cuvette. The aim of this technical note is to demonstrate the importance of the volume used during the push and to determine the lowermost volume limit for a µcuvette. The reduction of Dichloroindophenol (DCIP) by Ascorbic Acid at pH=2 is used for the determination of this minimal volume.