CS239536B1 - Method for determination of active chlorine content in hypochlorite and chloramine solutions - Google Patents

Abstract

In the determination method, a solution of hypochlorite or chloramine with free chlorine is introduced into a solution consisting of 2 to 0.1 mol.l"x potassium bromide in 5 to 0.1 mol.l"! inorganic acid and the change in potential is measured using a platinum measuring electrode. The determination according to the invention can find application in the analysis of hypochlorites, chloramines and their mixtures in the textile industry, in medicine and in the military field.

Description

239 536

The invention solves determination of 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 .: From Inorg. und allg. Chem., 268, 244, 1952). Others postulate oxidation due to the release of atomic oxygen or free halogen (Bishop, J., Jennings, V.J .: Talanta, 1, 197, 1958; Bishop, B., Jennings, V.J .: Talanta, 8, 22, 1961).

In practice, the iodometric titration method or the titration method using arsenite or hydrazine sulphate (Narkus, P.K .; Prokopčík, A.J.) Is used to determine the active chlorine content of hypochlorite and chloramine solutions.

OF. analit. Chim., 16, 323 (1961). These classical assays are very lengthy and chemical-intensive.

The aforementioned drawbacks are eliminated by the method of the invention, which is based on a method for determining the active chlorine content of hypochlorite and chloramine solutions by direct potentiometry, wherein a solution of hypochlorite or chloramines with free chlorine is introduced into a potassium bromide solution in sulfuric acid medium. platinum electrodes.

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

239 536

From the basic solution 1 tnol.l “! of potassium bromide, 1 mol ^/ l sulfuric acid was measured with 15 ml of the 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, only the base solution was measured with 10 ml into 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 determination error achieved in the concentration range 0.05 to 0.001 percent active chlorine did not exceed 5 percent.

Example 3

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 239 536 Method for determining the content of active chlorine in hypochlorite solutions and chloramines direct potentiometry, characterized in that sodium hypochlorite or chloramine free chlorine was added to a solution comprising 2 to 0.1 M of potassium bromide in ¹ to 5 ¹ 0.1 M inorganic acid, such as sulfuric acid, and potential change is measured using a specific platinum electrode.