SU1286971A1 - Method of determining aniline vapor in air - Google Patents

Abstract

The image refers to analytical chemistry, in particular to the method for the quantitative determination of aniline vapor (A) in air. An increase in the sensitivity of the method is achieved due to an indicator solution (IL) of a different composition. The determination of vapor A is carried out by absorbing the analyte IR, followed by photocolorimetry of the obtained colored solution. IR has the composition, wt;%: p-dimethylaminobenzaldehyde 1.0-1.5; forssoric acid 1-2; hydroquinone 0.1; ethyl or isopropyl alcohol to 100. The sensitivity of the determination in comparison with the known method increases from 0.82 to 0.05 µg / ml with a lower consumption of IL-10 ml versus 25 ml, i.e. sensitivity as a whole is 40 times higher than the known. 3 tab. In l

Description

112

The invention relates to sanitary and hygienic control of the air environment, to methods for the quantitative determination of aniline vapor in the air.

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

The method is carried out as follows.

8 MP indicator solution is poured into the absorption device and 2 to 10 liters of analyzed air is passed through it with a flow rate of 0.7 l / min. As an indicator solution using an acidic solution of p-dimethylaminobenzaldehyde in ethyl or isopropyl alcohol, and an acidic solution of p-dimethylaminobenzaldehyde in ethyl or isopropyl alcohol is used in the following ratio of components% by mass:

p-Dimethylaminobenzal degida Phosphoric acid

 Hydroquinone

Alcohol Else The absorber contents are transferred to a 10 ml graduated colorimetric tube, the absorber is washed with 2 ml of indicator solution, the volume of the solution in the tube is adjusted to 10 ml and photocolorimetric with a blue filter. The concentration of aniline in the analyzed air is determined according to a previously plotted optical density - and on concentration.

When applying the proposed method, the sensitivity of the determination of aniline is significantly increased (see Table 1).

Spreadsheets

1-1,5 1-2

Known 0.82

1.64 2.46

way 0,003 0,065 0,090

 Continued table.

fO

The proposed method

five

0

five

0

one

five

As can be seen from the results given in table. 1, the lower limit of the detection of aniline by the proposed method is more than 16 times less than that of the known method (0.05 µg / / ml instead of 0.82 µg / ml). In addition, a larger volume of an indicator solution of 25 ml is used in the antiviral method according to a known method, and in this one 10 ml, which requires a larger amount of aniline to create the desired concentration in the analyzed solution and, accordingly, necessitates the use of large volumes of the analyzed air. - ha.

The amount of aniline in the indicator solution at the limit of sensitivity in the known method is 0.02 mg, in the proposed method - 0.0005 mg. The volume of air required for accumulation of the indicated amount of aniline with a concentration of 0.1 mg / m (CC) in the known method is 200 m, in the proposed m-5 m.

Thus, if we express the sensitivity of the method in mg of aniline in the analyzed volume of the solution, the sensitivity of the proposed method; Soba is above 40 times.

In tab. 2 shows the dependence of the sensitivity of the indicator solution on the nature of the solvent.

312869714

Table 2

Optical density of p-dimedeniline tylaminobenzaldehyde solutions after reaction with in the sample, mg aniline

in aqueous solution in alcohol

re-g ™

isopropyl i ethyl

0,001 0,0180,102 0,110

0.003 0.050.279 0.292

The data show that the indicator solution in 5-6

use as solvent P g.

p-dimethylaminobenzaldehyde indicated-.20 ° the concentration of the main alcohol increases the sensitivity of the indicator solution sludge; luster in table. 3

-. . (g a b l and c a 3

Concentration Quantity Concentration Optical

1 DMAB to rast-add. Ani-N PO in plant density

: thief,% ling, milliwort,% solution

h

0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001

0.00

0.021

0.103

0.105

0.086

0,102

0.091

0.104

Claims (1)

The claims of the invention ^ A method for determining aniline vapor in air by absorbing an analyte with an indicator solution followed by photocolorimetry of the obtained colored solution, characterized in that, in order to increase the detection sensitivity, a solution of the following composition is used as an indicator solution, wt.%: · N-Dimethylaminobenzaldehyde 1.0 -1.5 Phosphoric acid 1-2 Hydroquinone. 0.1 Ethyl or isopropyl alcohol Up to 10 ° C