SU1295306A1 - Method of quantitative determining of phosphonates in water - Google Patents

Abstract

The invention relates to analytical chemistry, in particular, a method for the determination of phosphonates in water, and can be used in the analysis of the cooling water of heat exchangers of power plants. To speed up and simplify the analysis, before photometry of the solution obtained after processing a sample of saltwater after heating it, o-tolidine, benzidine, methyl orange, p-phenetidine or pyrocatechol violet are introduced into it. The method provides a reduction in the time and number of operations 2 times. Table. (L с: ГЧЭ co-eaten

Description

The invention relates to an improved method for the quantitative determination of phosonates in water, which can be used in the analysis of station cooling water.

The purpose of the invention is to accelerate and simplify the method of determination.

Example 1. For determination, take solutions of substances: 0.001 n. a solution of cerium sulphate at 1 and. sulfuric acid and a 0.05% solution of o-tolidine on 2 n, sulfuric acid.

Aliquots of the analyzed solutions with a content of 0.001-0.05 mg of phosphonate are introduced into glasses with a capacity of 100 ml, diluted to 20 ml with distilled water, 1.5 np of ceric acid solution are added and heated in a boiling water bath 2-3. min After cooling, the solution is transferred into a 50 ml volumetric flask, injected with 1 ml of o-tolidine solution, diluted to the mark with distilled water, mixed and the optical density is measured using an orio photoelectric spectrometer 400 nm in a cell with a 50 mm absorbent layer to distilled water

EXAMPLE 2 For the determination, solutions of the substances are taken: 0.001 N, a solution of cerium sulphate on 2 1, sulfuric acid and a 0.05% aqueous solution of benzidine hydrochloride.

Aliquots of the analyzed solutions with a content of 0.001-0.05 mg of phosphonates are introduced into glasses with a capacity of 100 ml, diluted to 20 ml with distilled water, 1.5 ml of cerium sulphate solution are added and heated in a boiling water bath. 2-3 missions The solution is then transferred to a 50 ml volumetric flask, 1 ml of benzidine hydrochloric acid solution is diluted to the mark with distilled water, mixed and the optical density is measured using photoelectric polarizer at 400 nm in a cell with an absorbing layer 50 mm thick. with respect to distilled water. II p and me R 3. For the determination take solutions of substances: 0.001 n. cerium sulphate solution by 2 n. sulfuric acid and a 0.005% aqueous solution of methyl orange.

Aliquots of the analyzed solutions with a content of 0.005-0.1 mg 4 osphonates are introduced into glasses with a capacity of 100 ml.

diluted to 20 ml with distilled water, add 3 ml of cerium sulphate solution and heat on a boiling water bath for 2-3 minutes. Then the solution is transferred to a 50 ml volumetric flask, 1 ml of methyl orange solution is added, diluted to the mark with distilled water, mix and measure the optical density using a photoelectrocolorimeter at 490 nm in a cuvette with an absorbing layer thickness of 50 mm with respect to distilled water.

The content of phosphonates in the analyzed samples is found according to the corresponding calibration graphs.

To construct calibration graphs, standard solutions are prepared containing 0.001-0.1 mg of phosphonic acid in a sample, diluted to 20 ml with distilled water, and then do the same as with the analyzed sample. The calibration curve is plotted, the content of phosphonic acid in the sample is plotted on the horizontal axis, and the optical density is plotted on the vertical axis.

Accuracy characteristics of the proposed method are verified by the additive method. The results of the static treatment are given in Table. one.

The results of the determination of HEDP and NTF in natural water (salt content 860, mg / l, hardness 6.2 mEq / l) used to cool the heat exchangers at the thermal power plant, according to the proposed and well-known tabl, 2, 1

Table 3 shows the comparative characteristics of the proposed and known methods.

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Claims (1)

Invention Formula The method of quantitative determination of phosphonates in water by treating an analyzed sample of a salt of a cerium when heated in a boiling water bath, followed by photometry of the resulting solution, characterized in that ne55 way to speed up and simplify O-tolidine or benzidine or methyl orange or p-phenetidine or pyrocatechol violet are introduced by photometric measurements. T a b ln c a 1 Table 2 3 I Feature Offered Known Analysis time, min ten Cerium sulfate One of the things on TV: o-tolidine, benzidine, methnlo-bbuij orange Not more than + 15 rel.% Editor E. Papp Representative S.Hovanska Tehred I.Popovich Proofreader L.Pilipenko Order 612/51 Circulation 777 Subscription VNIIPI USSR State Committee on cases of discoveries and discoveries 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and printing company, Uzhgorod, st. Project, 4 Table3 20 2 Cerium sulfate Sulfuric acid. Ammonium molybdenum-acid. Tin chloride Not more than 15 rtn. /