CS239632B1 - Method for determination of active chlorine content in hypochlorite and chloramine solutions - Google Patents

Abstract

The solution concerns a method for determining the active chlorine content using a simple, low-cost direct potentiometry method. This purpose is achieved by using the proposed method of determination, in which a solution of hypochlorite or chloramines with free chlorine is introduced into a solution consisting of 10~2 to 10-4 mol. I-·1- manganese sulfate with 2 to 0.1 mol.l-1 potassium bromide in an environment of 5 to 0.1 mol.l-1 inorganic acid and the change in potential is measured using a platinum measuring electrode. The solution can find application in the analysis of hypochlorites, chloramines and their mixtures in the textile industry, in medicine and in the military field.

Description

(54, Method for determining the content of active chlorine in hypochlorite and chloramine solutions

The present invention relates to a method for determining the active chlorine content using a simple, straightforward method of direct potentiometry.

This is achieved by using the proposed assay method in which a solution of hypochlorite or chloramines with free chlorine is introduced into a solution of 10 -2 to 10 ^-4 mol. I ^{- 1} - manganese sulphate with 2 to 0.1 mol.l ^-1 of potassium bromide in a medium of 5 to 0.1 mol.l ^{-1 of} inorganic acid and the potential change is measured using a specific platinum electrode.

The solution can be used in the analysis of hypochlorites, chloramines and their mixtures in the textile industry, in medicine and in the military field.

The invention solves the determination of the active chlorine content in hypochlorite and chloramine solutions by direct potentiometry.

Chloramines and hypochlorites are used in analytical chemistry, in the textile industry, in the military field, and in medicine (Afanasjev, B. N.: Usledchi chimii, 21, 69, 1952). Their oxidation and chlorination effects are used here. Most authors attribute the oxidative effects of these compounds to hypochlorous acid (Komarovskij, A. S., Filonova, V. F., Korenman, J. M.

OF. he said. chim. 6, 742 (1933); Poethke, W., Wolf, F., Z. anor.g. und allg. Chem. 268, 244 (1952). Others assume oxidation due to the release of atomic oxygen or free halogen (Bishop, E., Jennings, V.J .: Talanta, 1, 197, 1958; Bishop, E., Jennings, V.J .: Talanta, 8, 22, 1961).

In practice, the iodometric titration assay or the titration assay using arsenite or hydrazine sulfate is used to determine the active chlorine content of hypochlorite and chloramine solutions (Narkus, P. K., Prokopčík, A. J .: Analit. Chim. 16, 323, 1961). These classical assays are very lengthy and chemical-intensive.

The above drawbacks are eliminated by determining the present invention, whose essence is the method of determining the content of active chlorine in hypochlorite solutions and chloramines direct potentiometry, when sodium hypochlorite or chloramine free chlorine was added to a solution consisting of ¹⁰ to 2 to 10 ^{4 -4} mol.Å sulfate manganese 2 to ^-4 0.1M potassium bromide in an environment of 5 to ^-1, inorganic 0.1M sulfuric acid and the change in potential measured with a platinum electrode density. Under these conditions, the oxidative effects of active chlorine, both hypochlorites and chloramines, are quantitatively manifested.

The assay according to the invention is fast, simple, accurate and particularly suitable for series analysis.

Example 1

From the basic solution 10 mol m ^{-3 -1} manganese sulfate, 1 mol m ^-1 of potassium bromide in 1 mol.l ^-3 sulfuric acid were metered in 15 ml of solution into a 50 ml beaker. A pair of electrodes, a shiny platinum electrode, rinsed in concentrated sulfuric acid and distilled water, and a saturated calomel electrode were immersed in the solution. The solution was then pipetted with 1 ml of a chloramine solution with a measured content of active chlorine. The electromotive force of the galvanic cell was measured and the active chlorine content was subtracted from the calibration graph. A calibration graph showing the dependence of the platinum electrode potential on the active chlorine content of the solution was obtained by measuring a set of calcium hypochlorite solutions standardized by the iodometric titration method. The relative determination error achieved in the concentration range 0.5 to 0.01 percent active chlorine did not exceed 3 percent.

Example 2

The sensitivity of the assay can be increased by adjusting the workflow. The determination was carried out as in Example 1, except that only 10 ml of the stock solution was measured in a 50 ml beaker and 10 ml of a hypochlorite solution with a measured content of active chlorine was pipetted into this solution. The relative error of determination achieved in the concentration range 0.05 to 0.001 percent active chlorine did not exceed 5 percent.

Example3,

The assay was performed as in Example 1. However, a mixture of hypochlorite and chloramine was pipetted. The relative determination error did not exceed 3 percent, as in Example 1.

Claims (1)

SUBJECT OF THE INVENTION Method for determining the content of active chlorine in solutions of hypochlorites and chloramines by direct potentiometry, characterized in that the analyzed solution of hypochlorites or chloramines with free chlorine is introduced into a solution consisting of 10 ^-2 to 10 "^ mol.l"! manganese sulphate with 2 to 0.1 mol.l ^-1 potassium bromide in a medium of 5 to 0.1 mol.l ^-1 inorganic acid, for example sulfuric acid, and the change in potential is measured using a specific platinum electrode.