SU1558953A1 - Method of obtaining luminescent sensor of oxygen - Google Patents

Abstract

The present invention relates to a method for producing a luminescent oxygen sensor and makes it possible to increase the stability of the fluorescence parameters of a sensor. The silica gel is treated with dimethyldichlorosilane, then impregnated with an alcohol solution of trypaflavin and dried. 2 tab.

Description

The invention relates to analytical chemistry, in particular to the manufacture of luminescent sensors for the quantitative determination of oxygen in gases, and can be used to quickly and sensitively monitor the oxygen content in inert gases, nitrogen and air in the region of 0-100% (from atm. ).

The determination of oxygen is based on quenching the fluorescence of sensors with oxygen.

The aim of the invention is to increase the stability of the sensor.

PRI me R. In the manufacture of sensors, which are adsorbents of an activator on silica, industrial silica gel KSK-2 (specific surface 338 m2 / g, average pore radius 7 nm) and SSC (300 m2 / g and 6 nm) fractions of 0.1-0.6 mm. The use of these silica gels

This is caused not only by the fact that they have a rather large average pore radius (2 nm), but also by the fact that they are vitreous and have a developed surface. Silica gel washed from possible impurities, treating them first HCl (1: 1), and then with water.

Dimethyldichlorosilane is used to hydrophobize silica gels. Hydrophobization is carried out in the gas or liquid phases, special attention is paid to the exclusion of the formation of polymolecular layers of silicone derivatives on the surface of silica gel, which could reduce the average radius of the sorbent pores and the sensitivity of the sensor to oxygen. To do this, before treating dimethyldichlorosilane, the sorbent samples, the solvent (CC1 ±), and the carrier gas are dehydrated

Tripaphlavin is used as a fluorescent activator.

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with

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(TPF), since it has a high quantum yield of fluorescence and its fluorescence is quenched with oxygen with relatively high rate constants: greater, for example, than in the case of uranin or rhodamine BJ. In addition, the spectral characteristics of the TFTs allow the use of simple photoluminescence excitation sources and radiation detectors.

TPP is introduced into unmodified hydrophilic silica by sorption from an aqueous solution, and into hydrophobicized materials by impregnation with an alcoholic solution of a dye. The resulting adsorbents contain about mol TPP per 1 g of silica gel. The adsorbates are dried at 120-НО С in during the hour. The dried adsorbates are stored in containers with well ground stoppers in the dark. Under such storage conditions, TPF adsorbates retain their spectral and luminescent characteristics relatively well, i.e. does not fade. However, outdoors, even in the dark, the TPF fades in a silica sorbent. The process is accelerated by the action of light, but the TPF photo-efflorescence process in fluorescent sensors can be minimized by attenuating the excitation light, therefore it is important to increase the tempo stability of the dye.

In tab. Figures 1 and 2 present the estimates of the dark fading of the TPF in silica (G is the hydrophobic sample, and the index contains the number of the experiment in water repellency), with the degree of fading. estimated by the ratio IkCJf / Ic, where I ref is the fluorescence intensity of the adsorbate stored after being obtained in the dark in a closed container, 1C is the fluorescence intensity of the same adsorbate aged or in the open air at room temperature (Table 1), or in closed ampoules at 170 ° С, adsorbates placed at 70% humidity are placed in ampoules (Table 2) „The values of the fluorescence intensity of the adsorbate samples are determined at room temperature in air atmosphere c. identical conditions using a laboratory fluorimeter. The closer the ratio of TUOK / IC to one, the higher the stability of the TPF, and accordingly the higher the stability of the sensor. In the first approximation, the rate of destruction of the dye is characterized by the quantity (1), referred to the unit of aging time.

Table 1

20

table 2

Some increase in fluorescence after aging.

The data presented in Tables 1 and 2 show that the hydrophobization of the silica base can greatly inhibit the dark destruction of the TPF in the sorbent. So, during aging of adsorbates in the open air at room temperature, the destruction rate of TPF in hydrophobized silica KSK-2-G is approximately 5 times less than

in unmodified hydrophilic KSK-2 (Table 1). With accelerated aging of wet adsorbates in sealed ampoules at 170 ° C, an even greater decrease in the rate of TP destruction is observed when the base of the adsorbates is hydrophobized (Table 2).

Thus, the proposed method for the manufacture of a luminescent oxygen sensor based on a previously hydrophobised silica sorbent significantly increases the sensor stability. When the fluorescence intensity of the sensor is stabilized by reducing the fading of the activator, the stability of the fluorescence quenching constant of the sensor with oxygen should also increase. Such an increase in the stability of the fluorescence parameters of the sensor should increase the reliability and reproducibility of the determination of oxygen with the aid of a sensor,

ten

15

oxygen is practically the same as sensors prepared by a known method.

Claims (1)

DETAILED DESCRIPTION OF THE INVENTION The invention includes a method for producing a luminescent oxygen sensor, which includes treating silica gel with a solution of tripaperna, characterized in that, in order to increase the stability of the sensor, the silica gel is preliminarily hydrophobized with dimethyldichlorosilane, and an alcohol solution of tripaflavin is used for treatment. Compiled by T. Chilikin Editor I. Perbak Tehred A. Kravchuk Order 818 Circulation 579 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR I3035, Moscow, Zh-35, Raushsk nab. v. V5 Production and Publishing Combine Patent, Uzhgorod, Gagarin str., 191 Proofreader O. Tsiple Subscription