SU1249451A1 - Method of kinetic determining of iron(ii) - Google Patents

Abstract

. The invention relates to a method of kinetic determination of iron, can be used in the analysis of water, chemicals, alloys, and allows you to increase the sensitivity and selectivity. Add M solution of indigo-carmine, 5% solution of tartaric acid, acetate buffer solution with pH to the analyzed water. 3.8-4.5, 3% hydrogen peroxide solution and after 5 min 1 M sodium hydroxide solution. The optical density of the solution is measured on a photoelectric calorimeter. In parallel, an idle analysis was performed. The iron content in the sample is found on the graduation curve (coordinates: iron content is the difference in the optical density of the test and blank solutions),

Description

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The invention relates to analytic chemistry and can be used in the analysis of water, chemical reagents, alloys.

The purpose of the invention is to increase the sensitivity and selectivity, simplifying the determination of iron (II).

Example 1 Determination of iron (I) in water.

. To 10 ml of the analyzed water was added 5 ml of a 2-10 M solution of indigocarmine, 1 ml of a 5% tartaric acid solution, 8 ml of an acetate buffer solution pH 3.8 and 0, 1 ml of a 3% hydrogen peroxide solution . After 5 min, the volume was adjusted to the mark with 1 M sodium hydroxide solution.

The optical density of the solution on a photoelectric calorimeter in cuvettes with a layer thickness of 1 cm and a light filter No. 6 with respect to water is measured. In parallel, an idle analysis was performed.

The iron content in the sample is found on the calibration curve, built in the coordinates of the iron content (V) - the difference between the optical density of the test and blank solutions after carrying out the reaction. In the analyzed water, the known content of Fe (I) is 0.06 mg / l, 0.060 + 0.003 mg / l is found, and 0.078 + 0.003 mg / l is found for the content of 0.078 mg / l. The relative standard deviation of the five definitions is 0.05 and 0.038, respectively. The method allows to determine up to 1 ng / ml. The calibration curve is linear in the range of 0.001-1 μg / ml Fe (I). Determination is possible at 15-30 ° C. The determination of 10 μg / ml of Fe (I) does not interfere with 1 μg / ml of aluminum, the nickname “w, copper, cadmas, iron (li), and also acetates, chlorides, nitrates, and sulfates.

The reaction of indigo carmine oxidation with hydrogen peroxide to colorless isatin has a low temperature coefficient and does not require thermostatic control.

Example 2. Determination of iron (IJ) in tartaric acid.

A weighed amount of 0.1 g of tartaric acid is dissolved in 5 ml of distilled water and is determined according to Example 1. The vines are added to the blank sample.

BNIIPI Order 4230/46 Circulation 778

Proiz.-poly. pr-tie, Uzhgorod, st. Project, 4

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nuyu acid. Fe (I) in tartaric acid (known content of 0.30 and 0.36) is determined to be 0.30 + +0.01 and 0.36 + 0.01, respectively. The relative 5 standard deviation of the five definitions is 0.048 and 0.028, respectively.

Froze Determination of iron in nickel alloy.

A 0.25 g alloy weight was dissolved in nitric acid (1: 1), transferred to a 50 m volumetric flask, and made up to the mark with distilled water.

In a 50 ml beaker, 5 ml of the analyzed solution, 1 ml of a 5% solution of tartaric acid, 5 ml of acetate buffer solution of pH 4.0-4.5 are placed and irradiated for 5 min with a mercury-quartz lamp at a distance of 15 cm from the irradiated surface to reduce iron (IM) to iron (I).

After irradiation, the solution is quantitatively transferred to a measuring flask with a capacity of 25 ml, and then determined as per example 1. E (M) in the alloy is determined (Fe content according to the passport is 0.019%) 0.019 + 0.001%. The relative standard deviation of the five definitions of O, 055.

To test the developed methodology using the method of additives. Known iron content 0,029%, found 0,028 + 0,001%. The relative standard deviation of the determination is 0.034. . Known iron content 0,038%, found 0,038 + 0,001%. Relative standard deviation of determination is 0.026.

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Claims (1)

Formula Eteni The method of kinetic determination of iron (IJ), including the oxidation of an organic reagent with hydrogen peroxide and the subsequent measurement of the optical density of the solution, in order to increase the sensitivity and selectivity, to simplify the determination of iron (H) , Indigo Carmine is used as an organic reagent, and the reaction is carried out at pH 3.8-4.5 in the presence of tartaric acid. Subscription