| 摘要 |
PURPOSE:To realize a reproducible simple quantitative method, by adsorbing an electrode absorbing substance concentratedly on the surface of a mercury electrode used for the working electrode to measure the peak when metal in liquid is deposited thereon in reduction by the differential pulse voltammetry (DPV) method. CONSTITUTION:In an electrode system in which a working electrode 2, an opposed electrode 3 and a reference electrode 4 are immersed into a liquid 5 to be inspected with a potentiostat 1, a mercury drop electrode is used as the working electrode 2. Then, the electrode 2 is held at a fixed potential for a certain time (determined by absorbing substance) beforehand to let the adsorbing substance adsorb on the mercury drop electrode to concentrate. Then, metal ion in the liquid is swept to the negative side from the positive side sandwitching the oxidation-reduction potential thereof (there is no elution of mercury as the sweeping potential moves to the negative by the DPV method side from the reference electrode potential of mercury) to measure the height or the area of the peak when the metal ion is electrically deposited in reduction. The existence of any adsorbing substance will lessen the peak thereby enabling the determination of the amount of the absorbing substance based on the relationship between the reduction and the amount thereof.
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