SU1559285A1 - Method of quantitative determination of 1-nitroso-1-alkylureas - Google Patents

Abstract

This invention relates to analytical chemistry, in particular, to a method for the quantitative determination of 1-nitro-1-alkylureas, which can be used in sanitary laboratories. The goal is to increase the selectivity of the method. The determination is carried out by sequential processing of the analyzed sample with an excess of alkali, an excess of sulfuric acid and an excess of alkali. The ammonia released is distilled off, captured with an absorption solution and titrated with a strong acid. The method allows one to selectively determine 1-nitroso-1-alkyl ureas in the presence of buffer mixtures, in buffered solutions, in natural and waste waters, and in mixtures comprising soil. 7 tab.

Description

The invention relates to analytical chemistry, and specifically to methods for the quantitative determination of 1-nitroso-1-alkyl ureas of the formula

B-N - C-NHo I If N0 O

 where R is CH, C HgCnH4nfl.

The purpose of the invention is to increase the selectivity of the method.

Example 1, Method of quantitative determination of 1-nitroso-1-methylurea (HMM) in the presence of phosphate buffer (KH2PO + NaOH).

A. A fine weight of HMM in the range of 0.20-0.26 g (under a tight) is introduced into a 500 ml distillation flask, 100 ml of freshly prepared 0.1 M phosphate buffer (pH 7) is added and, after dissolving the bulk substances added 5 ml of 20% sodium hydroxide solution. The mixture is stirred until the solution becomes colorless and the gas bubbles (diazomethane, nitrogen) are stopped, 10 ml of a 25% solution of sulfuric acid is added and stirred. After 15 minutes, 20 ml of a 20% sodium hydroxide solution are added, the flask is attached to an ammonia stripper and ammonia is distilled into a receiver with 20 ml of 4% boric acid and 6 drops of a mixed indicator (mixture 0, 1% alcohol

ate with

N3

00 SL

ten

15

thief methyl red with a 0.1% alcohol solution of methylene blue in the ratio of 2: 1). After distillation, the cooler tube is taken out of the liquid and distillation is continued for 2-3 minutes. Collect 75 ml of distillate and titrate with 0.1 n. solution of hydrochloric acid to change the color of the indicator, 1 ml of titrant corresponds to 0.01031 g. In parallel, a control experiment was conducted.

B, An accurate weight of NMM of about 0.05 g (under the throat) is introduced into a 500 ml distillation flask.

Next come, .As indicated in Example 1A, the distillation is titrated to 0.02 N. hydrochloric acid solution. 1 ml of titrant corresponds to 0.002062 g; In parallel, a control experiment is carried out,

The results of the quantitative determination of 1 mm of HMM in the presence of 0.1 M phosphate buffer (pH 7) with hMM additions.

in the range of 0.20-0.28 g (A) and about 25 0.05 g (B) are given in table 1.

Example 2, Method for quantitative determination of 1-nitroso-1-ethyl urea (CEM) in the presence of phosphate buffer (KH4P04 + NaOH). J0

0.5 g of HEM (exact weight) is dissolved in 10 ml of water (dissolution is carried out in a volumetric flask wrapped in opaque paper), 10 ml of solution (exact volume) is added in a quantity of 500 ml, where 90 ml of M phosphate buffer (pH 7) and 5 ml of 20% sodium hydroxide solution are pre-applied. Next come, as indicated in example 1A. Q The distillation is titrated to 0.02 n. a solution of hydrochloric acid, 1 ml of titrant. corresponds to 0,002342 g CjEjN O.

In parallel, a control experiment was conducted.

Fat buffer (pK 7) are given in table 3.

Example 4, Method for the quantitative determination of 1% solution of HMM in physiological sodium chloride solution (model of the dosage form),

2.0 g of HMM (exact weight) is dissolved (under a tight) in 200 ml of a freshly prepared solution of sodium chloride in a volumetric flask wrapped in light-permeable paper. Sampling is next,

And 25 ml of the solution (exact volume) is introduced into a 500 ml distillation flask, freshly boiled and cooled water is added to a total volume of 100 ml and then proceed as indicated in Example 1A. The distillate is titrated with 0.1 n. with a solution of hydrochloric acid, 1 ml of titrant corresponds to 0.01031 g. In parallel, a control experiment is carried out,

B, 5 ml of the solution (exact volume) is introduced into a 500 ml distillation flask, freshly boiled and cooled water is added to a total volume of 100 ml and then it is fed as indicated in Example 1A. The distillation is titrated with 0.02 N, hydrochloric acid acid, 1 ml of titrant corresponds to 0.002062 g of CaH4N304. In parallel, a control experiment was carried out.

The results of quantitative determination of a 1% aqueous solution of HMM in physiological solution of sodium chloride with a sample volume of 25 ml (A) and 5 ml (B) are given in table 4.

Example 5, Method of quantitative determination of a 0.1% solution of HMM in O, 1 M phosphate buffer KH4PO4 + + NaOH (pH 7),

0.5 g of HMM (exact weight) solution50

The results of quantitative determination (under throat) in 500 ml of 0.1 M phosphonate HEM in the presence of 0.1 M phosphate fat buffer in a volumetric flask, the over-buffer (pH 7) are given in Table 2.

Example 3. Method for the quantitative determination of 1-nitroso-1-butyl urea (NBM) in the presence of phosphate buffer (KH4PO + NaOH),

Proceed as indicated in Example 1B. The distillation is titrated with 0.02 N, a solution of hydrochloric acid, 1 ml of titrant corresponds to 0.02904. In parallel, a control experiment is carried out.

The results of quantitative determination of NBM in the presence of 0.1 M phosphate

55

A nougat into opaque paper, 50 ml of the solution (exact volume) are quickly introduced into a flask for distillation, into which 50 ml of water and 5 ml of 20% pactBopa hydroxide on ri are introduced. Next come, as indicated in example 1A. The distillate is titrated with 0.02 N, a solution of hydrochloric acid I ml of titrant corresponds to 0.002062 CaH4Y3Og. In parallel, a control experiment was carried out.

Results of quantitative determination of 1% solution of HMM in 0.1 M

0

five

0

five

J0

with Q

Fat buffer (pK 7) are given in table 3.

Example 4, Method for the quantitative determination of 1% solution of HMM in physiological sodium chloride solution (model of the dosage form),

2.0 g of HMM (exact weight) is dissolved (under a grip) in 200 ml of freshly prepared solution of sodium chloride in a volumetric flask wrapped in opaque paper. The following sample is taken:

And 25 ml of the solution (exact volume) is introduced into a 500 ml distillation flask, freshly boiled and cooled water is added to a total volume of 100 ml and then proceed as indicated in Example 1A. The distillate is titrated with 0.1 n. a solution of hydrochloric acid, 1 ml of titrant corresponds to 0.01031 g. In parallel, a control experiment is carried out,

B, 5 ml of the solution (exact volume) is introduced into a 500 ml distillation flask, freshly boiled and cooled water is added to a total volume of 100 ml and then it is fed as indicated in Example 1A. The distillation is titrated with 0.02 N, hydrochloric acid . acid, 1 ml of titrant corresponds to 0.002062 g of CaH4N304. In parallel, a control experiment was carried out.

The results of quantitative determination of 1% aqueous solution of HMM in physiological sodium chloride solution with a sample volume of 25 ml (A) and 5 ml (B) are given in table 4.

Example 5, Method of quantitative determination of a 0.1% aqueous solution of HMM in O, 1 M phosphate buffer KH4P04 + + NaOH (pH 7),

0.5 g of HMM (precise weight) solution

trough (under tight) in 500 ml of 0.1 M phosphate buffer in a volumetric flask;

A nougat into the opaque paper, 50 ml of the solution (exact volume) are quickly introduced into the flask for distillation, into which 50 ml of water and 5 ml of 20% pactBopa sodium hydroxide are introduced. Next come, as indicated in example 1A. The distillate is titrated with 0.02 N, a solution of hydrochloric acid I ml of titrant corresponds to 0.002062 g of CaH4Y3Og. In parallel, a control experiment was carried out.

The results of quantitative determination of 1% aqueous solution of HMM in 0.1 M

phosphate buffer (pH 7) are given in table.5.

Example 6. Method for the quantitative determination of HMM in river water (model solution, HMM concentration of 0.025%).

0.25 g of HMM (exact weight) is dissolved (under a pull) in 1000 ml of river water in a volumetric flask wrapped in opaque paper. 200 ml of the sample (exact volume) are introduced into a 500 ml distillation flask, into which 5 ml of 20% sodium hydroxide solution is preliminarily added, and after stopping the evolution of gas bubbles, 10 ml of a 25% aqueous solution of sulfuric acid is added. acid. Next, proceed as indicated in example 1A. Distillation is titrated with 0802 n, hydrochloric acid solution, 1 ml of titrant corresponds to 0.002062 g. In parallel, a control experiment was carried out.

The results of determining MMOs in river water are given in Table 6c.

Example 7. Method for the quantitative determination of HMM in river water in the presence of soil, phosphate buffer (KHjPfy -t-NaOH) and benzene (artificial mixture, HMM concentration 0.05%)

0.5 g of HMM (exact weight) are dissolved in a 1000 ml volumetric flask in a mixture consisting of 9 parts of river water and 1 part of a 1 M phosphate buffer, pH 6 (by volume), in which 10 are suspended. g of soil and 0.1 g of benzene per 100 ml of the mixture volume. The mixture is placed in a refrigerator for 15 minutes under darkened conditions for

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precipitation of pschva. Then 100 ml of the sample are taken, introduced into a 500 ml distillation flask, into which 5 ml of 20% sodium hydroxide is introduced. Next come, as indicated in example 1A. The distillate is titrated to 0.02 n. a solution of hydrochloric acid, 1 ml of titrant corresponds to 0.002062 g of C4H4KE04. In parallel, a control experiment was carried out.

The results of determining HMM in this mixture are given in Table 7.

As can be seen from the above examples, the proposed method allows to increase the selectivity of the determination of 1-nitroso-1-alkylureas in the presence of buffer mixtures and in buffered solutions; in natural waters; in the effluent of industrial waters including some organic compounds j in mixtures comprising; soil

Claims (1)

Invention Formula The method of quantitative determination of 1-nitroso-1-alkylureas, including the processing of the sample being analyzed with the caustic alkali, followed by titration with a strong acid, which, in order to increase the selectivity of the process, after the sample being analyzed with an excess of alkali, it is additionally treated with an excess of sulfuric acid and an excess of alkali followed by distilling off ammonia, absorbing it and titrating it with a strong acid. Table 1 71559285 table 2 Table 3 100 0.048970 , 049P7 ± ± 0.000437