Application of a multichannel dropping dispenser in segmented continuous flow analysis

A simple dual channel dropping dispenser has been used for the simultaneous introduction of aqueous solutions of sample and reagent directly into a continuous flow of an organic solvent. Each aqueous segment forms an enclosed reaction system, completely surrounded by a film of the organic phase, which prevents any carry over between segments. An analytical signal is measured directly on the moving segments of precisely defined volumes of the homogenized reaction mixture. The applicability of this "microbatch" technique for the determination of light-absorbing species, for sample dilution and one-standard calibration, and for providing acid-base titrations on a microlitre scale is demonstrated with simple examples.