SU1363032A1 - Method of determining oxygen in gases - Google Patents

Abstract

The invention relates to analytical chemistry, in particular to the field of luminescent analysis of inorganic substances, and can be used to determine trace amounts of oxygen in gases. The goal is to increase the detection sensitivity in the concentration range of 150-1000 µg / L. The method includes sorption of rhodamine dyes in the amount of 7-10 -3 -10 M-g, processing the sorbent with a lithium iodide solution and measuring the linear increase in the intensity of the delayed fluorescence of the sorbent surface. (L 00 O5 with OQ

Description

1363032 2

The invention relates to analytical (0.3 mm) in a beaker, 5 ml of chemistry is added, namely to the luminescent solution of rhodamine CZ and to the assay of inorganic substances, and can be used to determine the trace amount of oxygen in gases.

The purpose of the invention is to increase the sensibility for 5 minutes. The colorless liquid above the sorbent is poured off, before, —Bavl 10 ml of a 1 10 M solution of lithium iodide and stirred for 5 minutes. The liquid above the sorbent is drained and the sorbent is dried in air at

determination of oxygen in

stir for 5 min. The colorless liquid above the sorbent is poured off, before, —Bavl 10 ml of a 1 10 M solution of lithium iodide and stirred for 5 minutes. The liquid above the sorbent is drained and the sorbent is dried in air at

concentration range of 150-1000 µg / l. 0 room temperature. 0.1 g obtained Using rhodamine sorbent dye (the content of dyes is due to the large values of their fast fluorescence quantum yields, and the addition of lithium iodide

2) is placed in a cuvette, which is attached to a vacuum post with a forevacuum and diffusion mash-up by increasing the output to the triplet-15 pumps and a nitrogen trap, and

Vacuum the cuvette to 5-10 mm Hg. The dosing of oxygen in the cuvette is carried out by adding air (at a known temperature and pressure) from

20

the state of rhodamine dye molecules, which together leads to an increase in the detection sensitivity. Maximum detection sensitivity is observed at

7 X

the introduction of the dye in the number of X. When the dye content is less, the detection sensitivity decreases. When the content of the dye is greater than 3 x X 10 Mg, the detection sensitivity decreases and the dependence of the intensity of the delayed fluorescence on the oxygen concentration is nonlinear. The intensity of the delayed fluorescence of ZODs sorbed on silica molecules of rhodamine dyes in the presence of lithium iodide is associated with an oxygen concentration in the range of 130-1000 µg / l linear dependence, the slope of which is determined by the effective combined effect of external heavy atoms (iodides - ions) and triplet oxygen molecules for intercombination transitions in rhodamine dye molecules attached to the surface of the sorbent.

The intensity of the delayed fluorescence was measured on an installation consisting of a 1mm quartz cell, where silica (0.1 g) with a dye sorbed on it was placed, a laser LPITCH-4 excitation source operating in a mode of modulated small accurately measured volumes. the air introduced into the system to the volume of the cuvette is determined in advance. The intensity of the delayed fluorescence (Ijij) at a maximum of 25 of its luminescence (D 560 nm) is measured and plotted

calibration characteristic in the coordin. Oxygen concentration, µg / l.

in the range of oxygen concentrations of 150-1000 µg / l, the calibration characteristic is a direct

35

40

the line, and the intensity of the delayed fluorescence increases 18 times, the sensitivity coefficient is 0.034 and does not change with a change in the content of rhodamine C in the range. U –3 –Y – M – g.

The intensity of the delayed fluorescence does not change in the presence of nitrogen and helium (at atmospheric pressure). .. Example 2. KO, 2 g of Silochrom C-80 brand silica are added with 5 ml of an I-IO M solution of rhodamine 6G. Next, proceed as in example 1, and get the sorbent with a dye content of 2.5 to 10 M-g. In the range of oxygen concentrations of 150-1000 µg / l, the calibration characteristic is

Q-factor (20 n) with amplification is a straight line, intensity by IZ-25 body (energy mJ on delayed fluorescence increases 18 times, sensitivity coefficient is equal to 0.034.

1060 nm) and a frequency doubler based on niobate lithium (D 530 nm), an FEU-84 photomultiplier with an electric photo gate with a resolution time of 50 n and an S8-13 oscilloscope.

Example 1. KO, 2 g of Silochrom C-80 brand silica (fraction 0.255

For ethyl ester of unsubstituted rhodamia and butyl ether of rhodamine CS, the Bbmie values are similar.

0.3 mm) in a cup, add 5 ml of rhodamine CZ solution and mix for 5 minutes. The colorless liquid above the sorbent is poured off, before, —Bavl 10 ml of a 1 10 M solution of lithium iodide and stirred for 5 minutes. The liquid above the sorbent is drained and the sorbent is dried in air at

small accurately measured volumes. The ratio of the air introduced into the system to the volume of the cuvette is determined in advance. The intensity of the delayed fluorescence (Ijij) at the maximum of its luminescence (D 560 nm) is measured and

calibration characteristic in the coordin. Oxygen concentration, µg / l.

in the range of oxygen concentrations of 150-1000 µg / l, the calibration characteristic is a direct

ZO

35

40

the line, and the intensity of the delayed fluorescence increases 18 times, the sensitivity coefficient is 0.034 and does not change with a change in the content of rhodamine C in the range. U –3 –Y – M – g.

The intensity of the delayed fluorescence does not change in the presence of nitrogen and helium (at atmospheric pressure). .. Example 2. KO, 2 g of Silochrom C-80 brand silica are added with 5 ml of an I-IO M solution of rhodamine 6G. Next, proceed as in example 1, and get the sorbent with a dye content of 2.5 to 10 M-g. In the range of oxygen concentrations of 150-1000 µg / l, the calibration characteristic is

For ethyl ester of unsubstituted rhodamia and butyl ether of rhodamine CS, the Bbmie values are similar.

 one

PRI me R 3. Determination of oxygen in helium gas of high purity.

A sorbent is prepared as described in Example 1. The cuvette is evacuated, the analyzed gas is passed through the sorbent at atmospheric pressure, and the intensity of the delayed fluorescence is measured. The oxygen content is found according to the calibration characteristic, the construction of which is described in Example 1.

Found oxygen, µg / l: 1.3 ± 0.1, p 5.

Thus, the method allows to increase the detection sensitivity. In addition, the method is characterized by a small value of the lower limit of the determined oxygen content and high reproducibility of the analysis results - the minimum value of the relative standard deviation. I. Rybchenko editor Order .6396 / 32

Compiled by O. Badtieva Tehred M. Khodyuchch

Circulation 776 VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab. / d. four

Production and printing company, Uzhgorod, st. Design, And

630324

nor equal to 0.05. The dye sorbent retains its characteristics for at least six months; with at least one sample of the sorbent, you can perform at least two thousand analyzes.

Claims (1)

Invention Formula ten The method for determining oxygen in gases, including the sorption of basic dyes on silica and measuring the luminescence of the surface of the sorbent, 15 that with the fact that, in order to increase the sensitivity of the determination of oxygen in the concentration range of 150-1000 µg / l, silica containing rhodamine dye in 20, the amount of 7-10G -3-10 M, is treated with a solution of lithium iodide and measure a linear increase in the intensity of the delayed fluorescence. Proofreader V.Girn to Subscription