Single microdroplet/water extraction and in situ microanalysis by microcapillary injection and differential pulse voltammetry.

A redox species was extracted from water (50 x 10(-6) dm3) into a single micro-oil-droplet (30 x 10(-12) dm3) in contact with a microelectrode using microcapillary injection and manipulation techniques. Further, an in situ microanalysis of the solute in a single oil droplet was demonstrated by differential pulse voltammetry. The redox species of 10(-16) mol concentrated in the droplet could be quantitatively analyzed independently of the distribution coefficient of the solute between the oil and water phases. The potential of this technique was considered in terms of the preconcentration and separation as well as a microanalysis and an ultratrace analysis.