SU1453303A1 - Inversion volt-amperometric method of analyzing permanganate ions in aqueous solutions - Google Patents

Abstract

This invention relates to current-voltage methods for determining anions in aqueous solutions. The purpose of the invention is to increase the sensitivity and selectivity of the determination of nO. MpO 1 is concentrated on the surface of a silver electrode in the potential range (-0.03) - (- O, 04) V against a background of 0.02-0.05 M solutions of KNOj, NaNOg, СНзСООЫа or СН: СООК at pH 10, 5-11, b. Then, it takes cathode volt-amperograms and the concentration of MpO is determined by the height of the cathode peak in the potential range from -0.24 to -0.29 V: 2 Il.

Description

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This invention relates to analytical chemistry, in particular, to voltammetric methods for the determination of anions in aqueous solutions.

The purpose of the invention is to increase the sensitivity and selectivity of the determination of permanganate ions.

Figure 1 shows the current-voltage curves of a 0.02 M solution of potassium nitrate; figure 2 - dependence of the cathode peak emission on the concentration of permanganate ions.

The method for determining the permanganate ion is as follows.

B. A solution of the background electrolyte at a constant potential of from -0.03 to -0.04 relative to the saturated calomel electrode at a certain pH value of 10.5 to 11.5 concentrates the permanganate ions for a set period of time (depending on the concentration detectable ion in solution). After accumulating a sufficient amount of an insoluble precipitate of salt AgMn04, the cathode polarized electrode with a linear potential sweep, the cathode peak of the electrodissuance of the precipitate from the electron accumulation potential Ee to its complete dissolution is recorded.

As a background electrolyte, 0.02-0.05 M solutions of potassium or sodium nitrate can be used, as well as 0.02-0.05 M solutions of potassium or sodium acetate with the indicated pH. Potassium nitrate contains 1 10 2.5-10, 5-10 M permanganate ions 1 (1-0.03 V (rel. K.c.e.), Amine (time IIj),, 04 V / s (W - potential sweep rate), pH 10.5 (figure 1) Figure 2 shows the dependence of the height of the cathode peak on the concentration of permanganate ions in a 0.02 M solution of potassium nitrate, pH 10.5,

 min, 04 V / s. The lower limit of detectable concentrations. is 1 m.

The proposed method for the determination of permanganate ions in a solution has a fairly good reproducibility, rapidity, and can be used in the analysis of chemical reagents, preparations, and industrial technological objects containing permanganate ion as impurities. The relative determination error does not exceed 9%. The determination of permanganate ions does not interfere with the presence of a 100-fold excess of chloride ions, nitrate ions, acetate ions, oxalate ions, 4-fold excess of sulfate ions. The determination is prevented by the presence in the solution of comparable concentrations of bromide ions and iodide ions, phosphate ions.

Claims (1)

Invention Formula An inversion voltammetric method for determining permanganate ions in one solution, which consists in concentrating the detected ions from the test solution on the electrode surface in the form of a poorly soluble sediment, followed by recording cathode voltammograms, characterized in that, in order to increase the sensitivity and selectivity, permanganate ions are concentrated on a silver electrode in the potential range from -0.03 to -0.04 V against a background of 0.02 - O 05 M solutions of potassium or sodium nitrate, or potassium acetate or sodium acetate pH 10.5 - 11.5 with posledutoschey registration cathode current-voltage curves and the concentration of ions permanganat- determined by the peak height in the potential range of -0.24 to -0.29 V. About U.Stf -OM4 0,2t O. Sl eight 1216 Fie.2