SU1043534A1 - Naphtalene 1-amino-4,8-disulphoacid mono-sodium salt determination method - Google Patents

Abstract

METHOD FOR DETERMINING MONONATRIC SALT 1-AMINO-4,8-disulfonic naphthalene including photometry of the colored compound, characterized in that, in order to increase the sensitivity of the method, the analyzed sample is sequentially treated with zinc dust at 75-80 ° C, sodium hydrogen acetic acid pr.i and boiling, then a solution of ferric chloride (P1) at a pH of 1.0-1.2, followed by photometry of the resulting solution.

Description

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Ro 4 The invention relates to analytical chemistry, in particular, to the quantitative determination of the monosodium salt of α-amino-4,8-disulfonic acid naphthalene (amino-C-acid). A known method for determining 1-naphthol-4,8 disulfonic acid naphthalene by treating a sample of the analyte with phosphomolybdenum acid (Folin's reagent) with n following photometry of the obtained solution 1J. The disadvantage of this method is its non-selectivity. The closest to the invention in technical essence and the achieved result is a method for determining amino-naphthylsulfonic acids, including the amino acid 4, 8-disulfonic acid naphthalene monosodium salt by treating the analyte with naphthalene CL-sulfonic acid in the presence of sulfuric acid, followed by titration of the resulting solution at 15 ° C sodium nitrite solution with iodine starch paper as indicator 2. A disadvantage of the known method is its relatively low sensitivity. The goal is achieved in that according to the method for determining the monosodium salt of 1-amino-4,8-disulfonic acid naphthalene by treating the sample being analyzed successively first with zinc dust at 7580 ° C with sodium hydrosulfite in the presence of acetic acid at boiling, then growing; thief of ferric chloride (lj.i) at pH 1.0-1.2, followed by photometry of the resulting solution. To build a calibration graph, a standard solution of amino-C-acid (from 0.25 to 10 mg / l) was introduced into a series of 100 ml volumetric flasks, 5 ml of 1N each was added. solution of HC1 and on the tip of the spatula zinc dust. Heat for 15 minutes under reflux at 80 ° C. Add 2 ml of 30% acetic acid and 2 ml of freshly prepared hydrosulfite. The mixture is heated under reflux for 1 hour. The refrigerator is disconnected, alkalinized with sodium hydroxide solution until pH. Yun is boiled until the removal of NH3- Acidified with hydrochloric acid and boiled until SOj is removed. The resulting solutions are quantitatively transferred into a 100 ml volumetric flask, 0.5 ml each are added. The O.Cl of FeClj prepared in 0.1% hydrochloric acid solution. The volume is brought to the mark with distilled water and The optical density of the solutions was measured for 15 min. a grophotometer in a cuvette with an absorbing layer thickness of 1 cm at a wavelength of 595 im against a blank sample. The spectrophotometric determination of amino-C-acid is carried out as follows: 25 ml of the test sample with a substance content of up to 10.0 mg / l are introduced into a 100 ml conical flask and the sample is processed as in the construction of a calibration graph. Measurement of optical density is carried out against the background of a blank containing all reagents except for amino-C-acid. Example. Artificial samples were analyzed whose composition is close to the composition of polluted natural and waste waters and individual samples. 25 ml of the test sample with a substance content of up to 10.0 mg / d are introduced into a conical flask, treated with zinc dust at 75 ° C for 10 minutes, 2 ml of a zone solution of acetic acid are introduced with 2 ml of freshly prepared sodium hydrosulfite and boiled for . 50 min. Under reflux. The treatment of PECl 2 is carried out at a pH value of 1.0, the molar ratio is 1: 1. The results of the determination are shown in Table G1. 1 and 2 are statistically processed. Example 2. 25 ml of the test sample with a substance content of up to 10 mg / l are introduced into a conical flask, treated with 1 flashed dust at 80 ° C for 15 minutes, 2 ml of 30% acetic acid solution are injected , 2 ml of freshly prepared sodium hydrosulfite and boil for 60 minutes under reflux. The ReSTZ treatment is carried out at a pH value of 1.2, a molar ratio of 1: 1. The results of the determination are shown in Table. 3 and 4 are statistically processed. To obtain comparative data, similar samples were determined in parallel by known and proposed methods. The data are summarized in table. 5. The use of the proposed method of spectrophotometric determination of amino-C-acid provides, as compared with the basic object, the possibility of selective determination of amino-C-acid in the presence of other naphtha linsulfonic acids and a high sensitivity of 0.25 mg / l (58% higher than that of). Zestnogo way-),

Table 1

Amino Acid

Aminr-Acid.

table 2

6.30

0.67 g / l 8.40 g / l

Spreadsheets

Table 4

Claims (1)

METHOD FOR DETERMINING 1-AMINO — 4,8-DISULPHIC ACID OF NAPHTALINE MONOSODIUM SALT, including photometry of a colored compound, characterized in that, in order to increase the sensitivity of the method, the analyzed sample is sequentially treated with zinc dust at 75-80 ° C, sodium hydrosulfite in the presence of acetic acid upon boiling, then with a solution of ferric chloride (I!) at a pH of 1.0-1.2, followed by photometric analysis of the resulting solution. · 1043534 2