SU1622801A1 - Method of quantitative determination of phenol - Google Patents

Abstract

The invention relates to analytical chemistry, in particular the quantitative determination of phenol, which can be used in the manufacture of drugs based on phenol. The chain is an increase in detection sensitivity. To do this, the initial sample is treated with chloroform and isopropanol, followed by heating with an 8% aqueous KOH solution and measuring the fluorescence intensity in N, N-dimethylformamide and 10% ammonium hydroxide solution, taken in a volume ratio (9 - 4): 1. The concentration of the substance is determined according to a calibration graph. In this case, the minimum detectable concentration is 0.04 µg / ml against 5.50 µg / ml, and the aryl impurities do not interfere with such a reaction. 6 tab.

Description

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This invention relates to analytical chemistry, in particular to methods for analyzing phenol, and can be used in the analysis of drugs.

The aim of the invention is to increase the detection sensitivity.

Example 1. Determination of phenol in substance.

A precise weight of phenol (1.0-0.002 g) is introduced into a 100 ml volumetric flask and dissolved in i-propyl alcohol, the volume of the solution is made up to the mark (solution A). 1 ml of solution A is introduced into a 50 ml volumetric flask and the volume of the solution is made up to the mark with propyl alcohol (solution B). 0.5 ml of 8% potassium hydroxide and 0.5 ml of chloroform are added to 1 ml of solution B. The solution is heated in a water bath at 70-80 ° C for 15-20 minutes and the volume is made up to 5 ml with a mixture containing NN-dimethylformamide and 10% ammonium hydroxide in the ratio (4-9) 1. The fluorescence intensity is measured with an excitation of 396 nm and an emission of 486 nm. The concentration of the substance is determined from a calibration graph. The proposed method allows determination of 60 - 0.04 µg / ml.

The results of the determination of phenol in the substance are presented in table 1.

Example 2. Determination of phenol in homeopathic dosage forms.

0.5 ml of an alcoholic solution of phenol (3 x) is diluted to 10 ml with propyl alcohol. To 1 ml of the solution obtained was added 0.5 ml of 8% potassium hydroxide, 0.5 ml of chloroform and heated on a water bath for 15-20 minutes at 70-80 ° C. After that, the volume of the solution is made up to 5 ml with a mixture of N. N-dimethylformamide - 10% ammonium hydroxide (ratio (4-9): 1) and measured

The fluorescence intensity at R 22 I / 396 nm and I radiation 486 nm relate to a standard solution, treated like a sample of the analyzed solution and containing 10 µg / ml.

The results of the determination are presented in Table 2.

Example 3. Determination of phenol in the form of insulin.

0.1 ml of insulin for injection (4.0 units) was diluted to 10 ml with isopropyl alcohol. To 1 ml of the resulting solution was added 0.5 ml of 8% potassium hydroxide, 0.5 ml of chloroform, heated on a water bath for 15-20 minutes at 70-80 ° C and the volume was brought to 5 ml with a mixture of NN-dimethylformamide - 10% ammonium hydroxide in the ratio (4-9): 1 .. Fluorimetry was carried out at an excitation wavelength of 396 nm and an emission wavelength of 486 nm against a standard solution treated similarly to the analyzed sample and containing 3 µg / ml.

The results of the determination are presented in table 3

Data on the dependence of the intensity of fluorescence on the concentration of alkalis are given in table 4.

The dependence of the fluorescence intensity on the volume of 8% potassium hydroxide is shown in Table 5.

The dependence of the fluorescence intensity on the ratio of the volumes of N.N-dimethylformamide and 10% ammonium hydroxide is shown in Table 6.

As can be seen from the table. 4 and 5, the maximum fluorescence intensity is observed using 8% potassium hydroxide taken in a volume of 0.5 ml. When the volume of chloroform varies from 0.5 to 1.2, the fluorescence intensity varies slightly, therefore, for convenience of analysis, a volume of 0.5 ml is chosen.

The proposed method is more sensitive than the known (the detectable minimum of concentrations is reduced from 0.050 µmol / ml (5.5 mg / ml to 0.04 µg / ml, i.e. 137 times). The analysis is acceptable in the case of determining the amount of phenol in pharmaceutical preparations.Aryl neftecholnogo nature of this reaction does not give.

Claims (1)

Invention Formula A method of quantitatively determining phenol by treating the sample to be analyzed with chloroform and potassium hydroxide under heating, characterized in that, in order to increase the detection sensitivity, the treatment is carried out in an isopropyl alcohol medium, an 8% aqueous solution of hydroxide potassium is used as potassium hydroxide and the treatments measure the fluorescence intensity in M, M-dimethylformamide and 10% ammonium hydroxide solution, taken in a volume ratio (9-4): 1. Table 1 Table 2 Table3 Tables ab