SU1500915A1 - Method of determining manganase (vii) in solutions - Google Patents

Abstract

The invention relates to methods for the photometric determination of manganese (UE) in solutions. The method includes the introduction of reducing agent - ferrous sulfate, sulfuric acid to a concentration of 1 in the analyzed solution ^. 10 ^-4 - 1 ^. 10 ^-2 M, organic reagent - the basic dye of basacrylate red W, lithium chloride to a concentration of 7-9 M, extraction of the resulting ionic associate with toluene and subsequent photometric measurement of the extract. The molar repayment rate is 3.9 ^. 10 ⁵ , the detection sensitivity is 0.0007 mol / L, the relative error is 2–4%, the duration of the analysis is 10–15 min. Beer's law is performed in a concentration range of 0.5-5 µg / ml manganese. 2 tab.

Description

The invention relates to analytical chemistry, specifically to methods of photometric determination of trace amounts of manganese (VII) c. solutions. .

The aim of the invention is to increase the sensitivity of the analysis and accelerate the process.

Example 1. The analyzed solution is placed in graduated test tubes with ground stoppers, 0.2 MP 2 -10-3 M solution of Mohr salt is added to them (a portion of the salt is dissolved in a 0.02 M solution of sulfuric acid). After 2 minutes, 3.2 ml of a 13 M solution of lithium chloride (its concentration in the final solution is 8.3 M) are added, 0.3 ml of a 2-10-3 M solution of an organic reagent — basacrylbrystalline red F (chloride 2- ( n-dimethyl shnostiril) -1,3,3-trimethyl- (3n) indoles) (BCG), diluted to 5 ml, 5 ml of toluene are poured, extracted for 1 minute, the organic phase is separated, centrifuged and measure the optical. the density of the extract in 0.3 cm cuvette at D 575 nm on the spectrophotometer SF-26.

The mechanism of the reaction of manganese (VII) reduction, the formation of a colored ionic associate and extraction can be represented as follows (R is the CGY dye cation):

ABOUT

| W

SP

MpO; + 5Fe2 +

+ 8H - -

Mn2-5Fe3 + HBZO;

f.Cf

,

- (- 401 + R Li ce

(1) FeClJR;

p e. (toluene

The molar ratio of the proposed method is 3.910 (by a known method - 1.6 10). Sensitivity of determining О50007 mol / l (sensitivity by the known method 0.0017 mol / l) Relative error 2-4% (by the known method also 2-4%) „Duration of analysis 10-15 min (by the known method 50-60 min) . Bar's law is observed in the concentration range of 0.5-5 µg / ml of manganese (VII).

 PRI me R 2 Determination of manganese in a standard solution e containing 25.00 μg of manganese. The analysis is conducted as described in the example. 1, The reduction is carried out in the presence of 1 - M sulfuric acid, and the extraction is carried out from solutions containing 7 M lithium chloride,

2.02 μg of manganese “Relative standard deviation (n 6; P 0.95) was found in the solution .S J, 0.032,

Trick, Determination of manganese in a standard pacTBopej containing 2, 00 µg of manganese.

The analysis is carried out as described in Example 1. The reduction is carried out in the presence of 1 M sulfuric acid, and the extraction is carried out from solutions containing 9 M lithium chloride,

In the solution found 2.01, mcg nar. Ganza „Relative standard deviation (n 6; P 0.95) Sj, 0.024

In tab. Figure 1 shows the experimental data showing the dependence of the detection sensitivity on the content of sulfuric acid during the reduction.

Table 2 shows the experimental data showing the dependence of the sensitivity of the assay on the content of 3 lithium chloride solution during extraction.

ten

15

the analyzed solution of a reducing agent, a mineral acid, an organic reagent — the main dye, extraction of the resulting ionic associate with toluene, and subsequent photometry of the extract, characterized in that, in order to increase the sensitivity of the analysis and accelerate the process, iron sulfate (II ), as a reagent - basacrylate-brilliant red W, reduction is carried out in the presence of 1 1 -10 M sulfuric acid, and extraction is carried out from solutions containing 7-9 M lithium chloride.

Table 1

Table 2

Claims (1)

F ό r m a l invention A method for determining manganese (VII) in solutions, including introducing a reducing agent, a mineral acid, an organic reagent — a basic dye into the analyzed solution, extraction of the formed ionic associate with toluene and subsequent photometry of the extract, characterized in that, in order to increase the sensitivity of the analysis and speed up the process, iron (II) sulfate is used as a reducing agent, basacrylbrilpiante red Ж is used as a reagent, reduction is carried out in the presence of 1 Ί 0 ⁴ 1 · 10 ~ ² M sulfuric acid, and traction - from solutions containing 7-9 M lithium chloride.