SU1293588A1 - Method of quantitative determination of 4,6-dinitro-orthocresol and 2-acetamine-5-nitrothiazole - Google Patents

Abstract

This invention relates to analytical chemistry, in particular to the quantitative determination of 4,6-dinitro-0-cresol and 2-acetamino-5-nitrothiazole, which can be used in the definition of aromatic and heterocyclic nitro compounds. Improving the sensitivity and accuracy of the process is achieved by further treating the solution with a reagent before extraction and using another organic solvent. The analysis is carried out by dissolving the sample in an aqueous solution of alkali and treating with 2,3-, 5-triphenyltetrazol chloride at pH 9.0-9.2. The mixture is then extracted with chloroform and the extract is photometrized. The sensitivity of this method is up to 0.40 µg / ml versus 0.83 µg / mg. The accuracy of the analysis is enhanced by increasing the optical density of the solution at 8 times the same concentration. 2 tab. I (L

Description

And: the invention relates to analytical chemistry, namely, to a method for determining aromatic and heterocyclic nitro compounds.

The purpose of the invention is to increase the sensitivity and accuracy of the method.

Example 1. The definition of 4,6-β-dinitroorthoresol (DNOC).

A weighted portion of about O, 1 g (exact) DNOC is dissolved in O, 1 n. a solution of sodium hydroxide in a 100 ml volumetric flask and adjusted to the mark with 0.1 N, sodium hydroxide solution (solution no. 1). 2 ml of solution No. 1 is transferred to a 50 ml volumetric flask and made up to the mark with a buffer solution (solution No. 2). The concentration of DNOC in the second pacTBopie is about 0.00004 g / ml

1.5 ml of this solution is placed in a separatory funnel, 10 ml of chloroform and 8.5 ml of buffer solution with pH 9.0-9.2 are added. The resulting colored product is extracted with chloroform. The chloroform layer is separated and transferred to a 50 ml volumetric flask. The colored product is extracted three times with 10 ml portions of chloroform, the combined extraction is adjusted to a precise volume of 50 ml with chloroform. The optical density is recorded on a FEK-56M instrument in a cuvette with a working layer thickness of 50 mm with a No. 3 light filter (400 nm wavelength) against the background of the control solution. The calculation of the content of DNOC is carried out according to the equation of the calibration graph calculated by the least squares method: D 282500-0 + 0,0165, where D is the value of optical density; C - concentration of DNOC, g / ml.

The results of the quantitative determination of DNOC and the metrological characteristics for the ten definitions are presented in Table 1.

Definition of 2-, acetamino-5-nitrothiazole (nitazole).

A weighed amount of about 0.1 g (exact) of nitazole is dissolved in O, 1N. sodium hydroxide solution in a 100 ml volumetric flask and adjusted to 0.1 n with sodium hydroxide solution (mark no. 1). Then, 2 ml of solution No. 1 is transferred to a 50 ml measuring flask and made up to the mark with a buffer solution (solution No. 2). Koytsentra

The nitazol q in the second solution is about 0.00004 g / ml. 2 l of this solution is placed in a separating funnel, 10 ml of chloroform and 8.0 ml of buffer solution (pH 9.0-9.2) are added. The resulting colored product is extracted with chloroform. The chloroform layer is separated and transferred to a 50 ml volumetric flask. The dyed product is extracted three times with 10 ml portions of chloroform, the combined extraction is adjusted to a precise volume of 50 ml with chloroform. The optical density is recorded on the device FEC-56M in a cuvette with a working layer thickness of 50 mm with a No. 3 light filter (400 nm wavelength) against the background of the control solution. The calculation of the nitazole content is carried out according to the equation of the calibration graph calculated by the least squares method:

0

D 255000-C - 0.038,

where D is the value of optical density;

C is nitazole concentration, g / ml. The results of the quantitative determination of nitazole and the metrological characteristics for the ten definitions are presented in Table 2.

When using the proposed method, the accuracy of the analysis is increased due to the fact that the optical density of the solution at the same concentrations increases 8 times.

In addition, the sensitivity of the method is increased to 0.40 µg / ml (the sensitivity of the known method

0.83 µg / ml).

Claims (1)

Invention Formula The method of quantitative determination of 4,6-dinitroortocresol and 2-ace, tamino-5-nitrothiazole by dissolving the analyzed sample in an aqueous solution of alkali, extraction with an organic solvent and photometry of the extract, so that In order to increase the sensitivity and accuracy of the method, before extraction, the solution is treated with 2,3,5-triphensh-tetrazole chloride at pH 9.0-9.2 and as a grade. chloroform is used as the organic solvent. Table 1