SU1368725A1 - Method of determining sodium cyanoacetate - Google Patents

Abstract

This invention relates to analytical chemistry. The purpose of the invention is to improve the accuracy and reduce the analysis time. A sample of the analyzed sample is treated with 6-7 ml of a 2-3% aqueous solution of alkali and 2-3 ml of a 0.6-0.8% solution of picric acid. The resulting solution was spectrophotometrically. 1 tab. (L

Description

This invention relates to analytical chemistry and can be used in chemical, pharmaceutical and pharmaceutical industry to control the content of sodium cyanacetic acid - a raw material in the production of penicillin, purine preparations: caffeine theophylline, theobromine and sulfanilamide preparations.

The aim of the invention is to improve the accuracy and reduce the analysis time.

Conducting the treatment, analyze the samples with 6-7 ml of a 2-3% solution of alkali and 2-3 ml of a 0.6-0.8% solution of picric acid allows to obtain a colored complex for 30 minutes, stable for 20 minutes, - with a characteristic absorption spectrum in the UV region with a maximum at a wavelength of 520 nm.

The use of alkali solutions with a concentration below 2%, for example a 1% solution, leads to a slow incomplete formation of a colored complex. The use of alkali solutions of higher concentrations is impractical because the stability of the complex decreases with time to 10 minutes. The use of solutions of picric acid with a concentration below 0.6%, for example a 0.5% solution, does not cause complete saturation, the use of picric acid with a concentration of 0.7% and above leads to complete saturation and does not change the optical density the studied solutions. Submission to the basic law of light absorption is observed within concentrations of 0.002-0.012 m / ml.

Subjects that can be used are sodium intermediates containing sodium cyanoacetate in the production of medicinal products of caffeine derivatives, barbiturates, sulfonamides, etc. The remaining components of the intermediate product, sodium glycolate, sodium chloride, do not interfere with the determination of the main component. For the preparation of the standard solution, an exact weight of 0.1 g of cyanoacetic acid was taken. The concentration of the standard solution is 0.0001 g / ml. For preparation of the analyzed solutions, weighed samples of the intermediate product were 0.16-0.21 g. The largest value of the specific index was 0.

r

five

0

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absorption circuit registered at l 520 nm.

PRI m. 1. A precise weight (0.2 g) of the analyte is placed in a 100 ml volumetric flask, dissolved in water and adjusted to the V mark with water.

10 ml (V) of solution Y are placed in a 100 ml flask and brought to the Vj mark with water. A volume (5-7 ml) of a 2.5% solution of alkali and 2 MP of a 0.7% aqueous solution of picric acid was added to a 1 MP solution of V. Bring total volume to 10 ml with distilled water. In parallel, a control solution was prepared from (5-7 ml) 2.5% alkali alkali solutions, 2 ml 0.7% picric acid solution. Make up to the total volume of 10 ml with distilled water. The investigated solutions after 30 min spectrophotometery on a spectrophotometer (SF-26) with a thickness of 1 cm

(D, 0.55; D

and a wavelength of 520 nm is 0.61; BZ 0.59).

Thus, the choice of the alkali volume of 2.5% is in the range of 6-7 ml.

Example 2. The preparation of the test and control solutions was carried out according to the procedure described in Example 1.

Use a solution of alkali in the amount of 6 ml of different concentrations: 1-4%. When working with a 1% alkali solution, the formation of a colored complex proceeds slowly, over 60 minutes, the stability of the complex is 20 minutes (D, 0.23). When using 2 and 3% solutions of alkali, the colored complex is formed in 30 minutes, its stability is 20 minutes (D, 0.6; D, 0.59). The study of the complex, with an alkali solution of 4% showed that the formation of the complex takes 30 minutes, but the stability of 5 decreases to 10 minutes (D 0.59).

Thus, when choosing the optimal alkali concentrations, alkaline solutions of concentrations of 2-3% are found.

PRI me R 3. Optimum value of 0 volumes of picric acid solution.

The test and control solutions were prepared according to the procedure described in Example 1. The concentration and volume of alkali 5 are taken respectively 2.3% and 6 ml.

The concentration of picric acid solution is 0.7%, the volume of picric acid solution is 1-3 ml (D 0.49; D 0.6; Dj 0.59).

Therefore, when choosing a volume of 0.7% picric acid, 2-3 ml is optimal.

PRI me R 4. The optimal value of the concentration of a solution of picric acid.

Preparation of the test and control solutions was carried out according to the procedure described in Example 1. A solution of picric acid in a volume of 2 ml of different concentrations, 0.4-0.9%, was used. When working with solutions of picric acid of different concentrations (D, 0.55; DI 0.57; D, 0.59; D 0.6; BZ 0.6; De 605) the formation of the complex takes 30 minutes, the stability of the complex is maintained within 20 min.

Thus, when choosing the optimal concentrations of the solution of picric acid, the solutions are con-0.6-0.8%.

EXAMPLE 5 A sample of the sample (0.16-0.21 g) is placed in a 100 ml volumetric flask, dissolved in water, and the volume is made up with distilled water to a V mark, 10 ml (V) of solution V placed in a volumetric flask per 100 mp and brought to distilled with distilled water to mark V. To 1 ml of solution-V add 6-7 MP to a 2-3% alkali solution and 2-3 MP to 0.6-0.8% a solution of picric acid. Total volume 10 ml (test solution). At the same time, a standard solution was prepared by dissolving in a volumetric flask with a capacity of 100 MP, 6.1 g (precise weighting) of chemically pure cyanacetic acid. recrystallized (solution A), 10 ml of solution A is placed in a 100 ml volumetric flask, the solution is brought to the mark with distilled water; 1 ml of the standard solution (B) of cyanoacetic acid contains 0.0001 g / MP. A standard spectrophotometric solution is prepared in the same way as the test solution. After 30 min, the studied and standard solutions were spectrophotometrically recorded on an SF-26 spectrophotometer with a layer thickness of 1 cm and a wavelength of 520. Control-: the solution consists of 6-7 ml of a 2-3% alkali solution, 2-3 ml of a 0.6–0.8% solution of picric acid, the required amount of distilled water, a total volume of 10 ml ,

The content of cyano acetic acid in the analyzed pro687254

percent is calculated by the formula

  - LYlYiIOO. BCGTU

where DJ is the optical density of the studied solution;

D is the optical density of the standard solution;

p is the weighed portion of the sample being analyzed; V is the volume of the volumetric flask used to dissolve the weighed portion of the analyzed sample;

V is the volume of the sample solution analyzed for 2Q dilution;

V - volume of the volumetric flask, excluding

for breeding;

C is the content of cyanoacetic acid in 1 ml of the standard 25 solution;

1.26 - conversion factor;

X is the content of cyano acetic sodium,%.

15

thirty

The results of quantitative determination of sodium cyanoacetic acid are given in the table.

0

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EXAMPLE 5 An accurate weighed sample of the sample to be analyzed was 0.1929 g, placed in a 100 ml volumetric flask, dissolved in water, and the volume was adjusted to the mark V with distilled water. 10 ml (V) of solution V are placed in a 100 ml volumetric flask and volume is made up with distilled water to mark V. To 1 ml of solution V add 7 ml of 2.5% aqueous NaOH solution and 2 mp 0.7% - picric acid solution. Total volume 10 ml (test solution). At the same time, a standard solution is prepared by dissolving in a measuring cup with a capacity of 100 ml of 0.1 g of cyanacetic acid brand H.h. recrystallized (solution A). 10 ml of solution A are placed in a 100 ml volumetric flask, solution B is brought to the mark with distilled water; 1 ml of solution B contains 0.0001 g / ml of cyanoacetic acid. Then, after 30 minutes, the standard and test solutions are spectrophotometrized on an SF-26 spectrometer with a layer thickness of 1 cm and a wavelength of 520 nm. As a control

five

5 1368725. 6

Claims (1)

solution used 7 ml of 2.5% ras-formula of the invention of the solution of NaOH, 2 ml of 0.7% solution picric acid, 10 ml cyanuksusnodo determination method (DX 0.605; D 0.670) was adjusted. the sample analyzed by alkali solutions The content of cyanacetic acid NO and picric acid and research It is 59.08% of the solution obtained, according to the formula, which is distinguished in this way by the optimal level and with the fact that, in order to improve the analysis, they are accurate and reduce the time treatment of the analyzed sample 6-7 ml analysis, use 2-3% solution 2-3% aqueous solution of alkali and 2-3 ml of alkali in the amount of 6-7 ml and 0.60, 6-0.8% aqueous solution of picric acid; 0.8% solution of picric acid acid, spectrophotometry of the amount of 2-3 ml and spectrophotometrically irradiated solution with the thickness of the layer is the result of the obtained solution with a length of 1 cm and a wavelength of 520 nm. Waves 520 nm.