SU315117A1 - METHOD FOR QUANTITATIVE DETERMINATION OF HEXAMETHYLENEDIAMINE IN WASTEWATER - Google Patents

Description

This invention relates to analytical chemistry.

A known method for the quantitative determination of hexamethylenediamine (HMD) by treating a sample of the water to be analyzed with 2,4-dinitrofluorobenzene followed by the identification of the obtained colored compound by a known method, for example by colorherization.

However, the known method is not very sensitive, since in the wastewater, hexamethylenediamine is present in a mixture with other aliphatic diamines in minimal concentrations (less than I f per liter of wastewater).

In order to increase the specificity of the analysis, a method was proposed for the quantitative determination of hexamethylenediamine, consisting in that a sample of the water to be analyzed is treated with a solution of 1-dimethylamino-naphthalen-5-sulfonic acid chloride, followed by extracting the resulting product with an extractant, such as chloroform, thin-layer chromatography and elution chromatography. absolute alcohol.

The method allows to determine hexamethylenediamine in wastewater at a concentration of 1 u / l.

Example. 200 ml of test water containing 0.5–10 p / l of HMD (Note 1), in a 500 ml round-bottomed flask, are acidified with sulfuric acid (about 0.1 ml of concentrated H2SO4) and in a vacuum created by a water-jet pump at a temperature of 45 - 50 ° C. Distilled water. To the wet residue was added 5 ml of distilled water, 0.6 g of sodium bicarbonate, 20 ml of acetone and 0.5 ml of 1% acetone solution of 1-dimethylamino-11-naphthalen-5-sulfochloride (D. LMS) (note 2) and heated at 45 ° C for 15 min. After 15 minutes, the contents of the flask were quantitatively transferred to a 100 ml separating funnel and extracted twice with chloroform (60 ml), the chloroform extract was washed with 40 ml of distilled water, filtered through anhydrous sodium sulfate (1.5 g), which was washed with chloroform (about 5 -7 ml).

From the filtrate in a 100 ml round-bottom flask in vacuum at 40 ° C, the solvent is distilled to a residue volume of 0.4-0.5 ml. The residue with 1 ml loupets is applied quantitatively by frontal administration onto the starting line of an alumina chromatographic plate, a drop of a 0.001% aqueous solution of chloroform is placed at a distance of 1 cm and chromatographed in a solvent system of chloroform-ether ether.

m.p. 40-bOS) -methanol (15: 5: 1) (note 3). On a chromatographic plate, when illuminated with a mercury-quartz lamp, a band located on the same line with the spot of a witness is visually detected using a characteristic green fluorescence. The adsorbent with the next strip is transferred to a No. 3 glass filter and treated in separate portions of dry acetone (25 ml). The solvent is distilled off in vacuo from the filtrate in a 500 ml round-bottom flask. The dry residue is dissolved in absolute ethanol, transferred to a volumetric flask and made up to 10 ml. The fluorescence intensity of the resulting solution was measured on an EF-3M fluorometer with a BI filter. The amount of HMD in the tested β-sample of water is determined by the calibration curve (Note 4) and calculated by the formula

L V

Hr

where L is the concentration of the HMD in the test water, mg.l; V-volume of test water taken from

determinations, ml;

n- found the number of GMI on the calibration curve in a 0.2 l flask. Note 1. When determining the HMD in samples with a higher content of diamine, they start from a smaller sample volume, then diluted with distilled water to 200 ml.

In determining the HMD in the atmosphere, sample preparation is reduced to the suction of the test air through an absorption vessel containing 1.5-2 ml of distilled water acidified with sulfuric acid. The amount of test air to be tested is determined empirically for each production point to be monitored.

Note 2. A 1% acetone solution of the reagent is prepared by dissolving 0.1 g of DAAC in 12.5 ml of solvent. The shelf life of the solution for 2 weeks when stored in a sealed container of dark glass.

Note 3. Alumina is applied on a 9X18 cm glass plate (TU-P chromatographic) and rolled by a roller to obtain a uniform layer 1.5-2–2 mm thick. After applying the test substance and the witness to the starting line, the plate is placed in a cuvette with a mixture of solvents at an angle, taking into account the wetting of the bottom edge of the adsorbent layer. Notes 4. Construction of the calibration curve. To prepare a standard solution of HMD (10), on the analytical balance, 50 mg of freshly distilled HMD are precisely injected and dissolved in 500 ml of distilled water. 50 ml cooked

the solution is diluted with distilled water to a volume of 500 ml. Then 0.05; 0.02; 0.4 and 0.8 ml of the standard solution in 200 ml volumetric flasks are diluted with water to the mark and subjected to analytical manipulation

described above method.

The concentration of condensation products in the resulting alcohol solutions is measured by fluorescence intensity on an EF-3M fluorometer with a BI filter. To obtain

The calibration curve on the coordinates of the graph is plotted on the scale of the instrument and the concentration of the HMD, equivalent to the content of the condensation product in the prepared alcohol solutions. Calibration

The curve is subject to periodic verification.

Subject invention

The method of quantitative determination of hexamethylenediamine in wastewater by treating a sample of the analyzed water with an organic reagent with further identification

the resulting short compounds obtained by known methods, characterized in that, c) to increase the specificity of the determination, a solution of 1-dimethylaminonaphthalene-5-sulfonic acid chloride is used as a reagent, followed by extraction of the resulting product with an extractant, for example chloroform, chromatography of the extract in a thin layer and fluorometry the eluate in absolute alcohol.