SU1693544A1 - Method of chloride determination - Google Patents

Abstract

The invention relates to methods for the photometric determination of chlorides and can be used in the sanitary control of air. The purpose of the invention is to increase the sensitivity of the analysis. The essence of the proposed method consists in carrying out an analytical reaction of converting chlorides into an iron-rhodanide complex in the presence of acetic and perchloric acids with their content in solution,%: 60-80 and 3-8, respectively. The sensitivity of the assay is 0.1 μg / ml, in the prototype 0.5 μg / ml. 2 tab.

Description

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This invention relates to fo. determination of chlorides and can be used for sanitary air control.

The purpose of the invention is to increase the sensitivity of the determination of chlorides.

Example. Air at a rate of 20 l / min is taken to the filter AFA-VP for 1 min, wash off the selected sample of metal chloride with 10 ml of water. 10 ml of an aqueous solution containing 0.5-25 μg of chloride ion are placed in a 50 ml glass of heat-resistant glass, evaporated to dryness in a sand bath. To the cooled samples add 5 ml of the reactive solution, mix and measure the optical density using a photoelectric colorimeter at a wavelength of 490 nm. The reactive solution is prepared as follows. To 350 ml of acetic acid are added 50 ml of a 0.25% solution of mercury rhodanide and 100 ml of 2.5%

a solution of iron ammonium alum (2.5 g in 100 ml of an aqueous solution of perchloric acid 3: 2). The content of chloride ion in the sample is determined by a pre-constructed calibration curve.

Table 1 presents data on the effect of concentrations of acetic and perchloric acids in the reaction of the chloride ion with the mercury rodidin and iron ammonium alum.

From Table 1 it follows that the best results for the determination of chloride ion are obtained in a reaction mixture containing more than 60 vol.% Acetic acid and more than 3% perchloric acid.

Table 2 compares the results of the analysis of artificial solutions using known and proposed methods.

As can be seen from table 2, the sensitivity of the proposed method is 0.5 μg of chloride ion in the analyzed solution volume (5 ml 0.1

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µg / ml), which is 5 times higher than in the known method.

The proposed method is applied for the determination of sodium chloride as well as calcium chloride in the air.

The formula of the invention. A method for determining chlorides, which includes translating them into a complex compound with mercury rodanide and iron ammonium alum in an acidic medium and subsequent photometry, which is different. In order to increase the sensitivity of the assay, an acidic medium is created with a mixture of acetic and perchloric acids with their content in a solution of 60-80 and 3-8% by volume, respectively.

Table 1

table 2

Claims (1)

Formulas a. inventions A method for the determination of chlorides, including their conversion into a complex compound with mercury thiocyanate and iron-ammonium alum in an acidic medium and subsequent photometry, characterized in that, in order to increase the sensitivity of the analysis, an acidic medium is created with a mixture of acetic and perchloric acids when they are contained in a solution of 60 -80 and 3-8 vol.%, Respectively. Table 1 Concentration, vol. % The optical density in the determination of chloride ion (25 kg) X ± j? Acetic acid Perchloric acid 0 0 0 B 6 0.18 ± 0.005 10 6 0.22 ± 0.026 20 6 0.30 ± 0.005 40 6 0.42 ± 0.010 60 6 0.62 ± 0.020 70 6 0.62 ± 0.020 80 6 0.60 ± 0.020 60 0 Precipitate 60 2 and 60 3 0.62 ± 0.030 60 4 0.62 ± 0.030 60 8 0.60 ± 0.020 Table 2 15. Chloridion introduced, mcg Found chloride ion, X ± x (P-0.95; η = 6) μg The known method. The proposed method 0.5 0 - 0.5 ± 0.05 0,095 1.5, 1.2 ± 0.2 0.19 1.6 ± 0.05 0,03 5 6.2 ± 1.6 0.25 4.8 ± 0.16 0,03 25 26.2 ± 3.8 0.14 25 ± 0.96 0,03 Compiled by G. Tsoi Editor M. Blanar Tehred M. Morgenthal Corrector T. Paly Order 4076 Circulation Subscription VNIIIPI of the State Committee for Inventions and Discoveries under the State Committee for Science and Technology of the USSR '113035, Moscow, Zh-35, Raushskaya nab., 4/5 Production and Publishing Plant Patent, Uzhgorod, Gagarin St. 101