SU1376045A1 - Method of determining vanadium (iv) - Google Patents

Abstract

The invention relates to analytical chemistry, in particular, to methods for determining vanadium (IV), which makes it possible to increase the sensitivity and selectivity of the analysis. 0.25 ml of a 2 10 n solution of 4-diethyl amino phthalhydride, 0.5 ml of 0.1 M are introduced into a cuvette. a solution of KOH, 0.355 ml of bidistilled water, 0.5 ml of 10 Mastvore these lendiamine tetraacetic acid, 0.1 ml of 1 HjOj solution and 0.1 ml of vanadium sulfate solution. The amount of light is measured in the range of 5-30 seconds from the moment the sample is introduced. The vanadium content is found on the calibration curve. The sensitivity of the determination of vanadium is 5-10 µg / ml. 3 hp ff, 1 tab. with S cl

Description

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The invention relates to analytical chemistry, in particular to methods for determining vanadium (IV), and to be used for the analysis of industrial process solutions, natural and waste waters, food products and objects of biological origin.

The purpose of the invention is to increase the sensitivity and selectivity of the analysis.

Example T. A 0.25 ml of a 2-10 M solution of 4-diethyl-aminophthalhydrazine (DEAFG), 0.5 ml of a 0.1 M solution of KOH, 3.55 ml of bidistilled water, 0.5 ml 1 are injected into a cuvette. -Yu M solution of ethylenediaminetetraacetic acid (EDTA), 0.1 ml of 1 solution of HjGj, 0.1 ml of vanadn sulfate solution. The amount of luminescence is then measured at a time interval of 5-30 seconds from the moment the sample is introduced. The vanadium content is found according to the calibration curve. The sensitivity of the vanadium determination is 5.-10 µg / ml.

The table presents the results of the dependence of the sensitivity of the determination of vanadium on the solution pH at concentrations of DEAFG, EDTA, 1-10-M, 1 -lO-M-l and 2. respectively.

PH value

10.0 11.0 12.0 12.5 13.0

The sensitivity of the analysis, µg / ml 40 -10 10-10 5-10-Yu-YuO-Yu

Example 2. All components were introduced into the cuvette in the amounts indicated in Example 1, except for the amount of DEAPHG, which was injected with 0.2 ml 1. The amount of bidistilled water is introduced based on a total volume of 5 ml. The analysis is carried out as described in streamer 1. The sensitivity of the determination of vanadium (IV) is 10: µg / ml.

Example Z. All components are introduced into the cuvette in the amounts indicated in Example 1, except for the amount of DEAPHG, which is injected with 1 ml of 5 -10 M. The amount of double-distilled water is injected, based on a total volume of 5 ml. The analysis is carried out as described in Example 1. The sensitivity of the determination of vanadium. (IV) is 20 10 µg / ml.

Example 4. A cuvette is injected with all the components in the amounts indicated in Example 1, except for the quantity N., Oz J which is injected 0.1 ml.

five . The amount of bidistilled water is introduced based on a total volume of 5 ml. The analysis is conducted as. described in example 1. The detection sensitivity of vanadium (IV) is 12–10 µg / ml.

Example 5. A JL is injected into the cuvette with all components in the amounts indicated in Example 1, except for the amount of EDTA, which is injected with 0.5 ml.

0 5

0 5

0

five

5 -10 M. The amount of bidistilled water is introduced based on a total volume of 5 ml. The analysis is carried out as described in Example 1. The sensitivity of the determination of vanadium (IV) is 10-10 µg / ml.

Example 6. All components are introduced into the cuvette in the amounts indicated in Example 1, except for the amount of hydrogen peroxide, which is injected with 0.1 ml of 5-10 K. The amount of bidistilled water is injected, based on a total volume of 5 liters. The analysis is carried out as described in Example 1. The sensitivity of the determination of vanadium (IV) is 15 -10 µg / ml.

Example 7. All components were introduced into the cuvette in the amounts indicated in Example 1, except for the amount of EDTA, which was injected with 0.5 ml of 5-10 M. The amount of bidistilled water was introduced based on a total volume of 5 ml. The analysis is carried out as described in Example 1. The sensitivity of the determination of vanadium (IV) is 10,

The proposed method, in comparison with the known method, makes it possible to increase the sensitivity of the determination of vanadium 200 times.

The determination of trace amounts of vanadium under optimal conditions is not hampered by a 1000-fold excess of Ca, Mg ions,

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Claims (4)

1. A method for determining vanadium (IV) by its catalytic effect on the oxidation reaction of an organic compound by hydrogen peroxide and quantitative registration by a chemiluminescence method, characterized in that, in order to increase the sensitivity and selectivity of the analysis, 4-dythylamino is used as an organic reagent j 10-15 phthalhydrazide and the reaction is carried out in the presence of ethylenediaminetetraacetic acid at pH 11.0-12.5. 2. Method POP1, characterized in that a solution of 4-diethylamino-phthalhydride with a concentration (4-1000) is used. 3. Method pop.1, which is also distinguished by the fact that hydrogen peroxide solution with a concentration of (1-tO) is used. 4. Method POP.1, characterized., With the fact that they use a solution of ethylenediaminetetraacetic acid with a concentration of (5-500) 10 M.