Stripping Analysis Using Ion-Transfer Voltammetry at Liquid/Liquid Interface
Principles and theory of stripping ion-transfer voltammetry at the organic solvent (O)/water (W) interface are described, in which a thin O-film is used to preconcentrate an ionic substance by electroextraction followed by stripping analysis using linear sweep voltammetry or normal pulse voltammetry. For ease of handling, the thin O-film was gelled by adding poly(vinyl chloride) to make an O-gel electrode. Lead(II), cadmium(II) and zinc(II) ions behave reversibly or quasi-reversibly in voltammetric transfer at the O/W interface assisted by 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine (DPT) present in the O-phase. Thus, these ions at trace levels can be determined using stripping ion-transfer voltammetry with the O(DPT)-gel electrode. The detection limit was as low as a few tens of nmol/l of these ions. Simultaneous determination of two or more ions is possible when their half-wave potentials of ion transfer are reasonably separated.