SU471527A1 - Method for quantitative determination of oximes - Google Patents

Description

one

This invention relates to analytical chemistry and relates to the determination of compounds containing an oxime function using reagents that produce a color reaction with the test substance.

A known method for the quantitative determination of oximes by adding sulfuric acid to the analyte to conduct hydrolysis, determining the hydroxylamine formed using iron ammonium alum, followed by colorimetrization of the resulting short compound.

However, this method involves many intermediate operations. According to the proposed method, successively used aqueous solutions of alkali, phenol and alkali metal hypochlorite are used as a reagent. Oximes in aqueous solution, interacting sequentially with aqueous solutions of alkali, phenol and alkali metal hypochlorite, form an idophenol dye. For oximes, the reaction proceeds the same compared to the nitrogen-containing compounds studied so far.

Quantitative determination is based on the increase in light absorption of the solution of indophenol, resulting from the phenol-hypochlorite reaction with increasing concentration

OXYMES.

The optimal conditions for determining oximes are as follows:

a) phenol concentration of 4.56-5.45 mg per 1 ml of the test mixture;

b) sodium hypochlorite concentration of 0.420-0.866 mg per 1 ml of the test mixture;

c) temperature of interaction with phenol 20 ° С, with sodium hypochlorite 65-70 ° С;

d) interaction time with phenol 2 minutes, with sodium hypochlorite 30 minutes.

Using the given optimal conditions, a concentration curve is constructed, which is subsequently quantified. The high sensitivity of the method allows it to be used for the analysis of wastewater and reservoir water for the content of trace amounts of oximes.

Example. 1 ml of wastewater to be analyzed is poured into a wide 20 ml test tube, 8 ml of bidistillate is added, 1 ml of 1N. caustic soda solution and carefully moved. Then 1 ml of a solution of 5-5.5% phenol is added, shaken vigorously and kept at 20 ° C for

2 minutes. Thereafter, 1 ml of a 0.5-1% sodium hypochlorite solution is added to the reaction mixture, shaken again and kept in a water bath at 65-70 ° C for 30 minutes. Then the solution is cooled down.

test tube in a glass of water at room temperature, and colorimetric. In case the solution is too intensely colored, the wastewater is pre-diluted to obtain a color that matches the calibration curve.

A calibration curve is composed as follows: a graduated pipette is taken of 0.1-1 ml of 0.0002 M solution of the corresponding oxime with an interval of 0.1 ml and added to ten clean test tubes. Next come the same way as the analysis.

To plot the calibration curve, the arithmetic average value of the optical density of four parallel experiments is taken; Comrade

The table shows the oxime content in the reaction mixture.

The subject of the image.

The method of quantitative determination of oximes by introducing into the test solution a reagent that gives a color reaction with the test substance, followed by colorimetrization of the obtained colored solution, characterized in that, in order to increase the sensitivity and accuracy of determination, aqueous alkaline solutions of phenol are used as a reagent and alkali metal hypochlorite. Priority calculated from 04/12/69