Method for determining benzene series substances in atmosphere

A technology of benzene series and gas phase, applied in the direction of measuring devices, material analysis using sound waves/ultrasonic waves/infrasonic waves, instruments, etc., can solve the problems of expensive and bulky instruments, and achieve low power consumption, fast response speed, and good selectivity Effect

Inactive Publication Date: 2010-05-26
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although the method has high detection sensitivity and accurate quantification, the instrument required by this method is relatively large and expensive

Method used

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  • Method for determining benzene series substances in atmosphere
  • Method for determining benzene series substances in atmosphere
  • Method for determining benzene series substances in atmosphere

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] (1), 10MHz QCM quartz crystal resonator in absolute ethanol, ultrasonic cleaning, drying, QCM measurement fundamental frequency, record the precise frequency value f 0 =9.969742MHz, the chip is packaged for use;

[0030] (2), accurately weigh 105mg ionic liquid C 4 mimNTf 2 , dissolved in 7mL of chloroform to prepare a 15mg / mL coating solution.

[0031] (3), the cleaned 9.969742MHz quartz crystal oscillator is suspended in 15mg / mL ionic liquid C 4 mimNTf 2Soak in the chloroform solution of 30sec, treat that the volatile organic solvent chloroform on the wafer surface volatilizes completely.

[0032] (4) Purge the coated quartz crystal oscillator at 30°C with 90mL / min of high-purity nitrogen, the frequency will be stable in about 1h, and the frequency f will be measured on the QCM 1 =9.9624MHz, then the frequency reduction value |Δf|=|f 1 -f 0 |=|9.969742MHz-9.9624MHz|=7342Hz, that is, the decrease value of the oscillation frequency caused by the slight increase o...

Embodiment 2

[0034] Using the ionic liquid C prepared in Example 1 4 mimNTf 2 The piezoelectric chemical sensor composed of a QCM resonator with a sensitive film has measured the response of various concentrations of benzene gas in the concentration range of 100-6500ppm. figure 1 Shown is the real-time frequency response curve of the sensor to benzene gas, and the abscissa (%) represents the percentage of the corresponding measured gas concentration relative to the prepared saturated benzene gas concentration. It can be seen from the figure that the sensor has fast response speed and excellent reversibility, which is convenient for multiple and continuous measurements. as attached figure 2 Shown is the relationship curve between frequency change and concentration, showing a good linear relationship (R 2 =0.9992), so the concentration of the gas to be measured can be obtained by measuring the frequency decrease value caused by a certain concentration of benzene gas on the sensor, and ac...

Embodiment 3

[0038] Using the ionic liquid C prepared in Example 1 4 mimNTf 2 The piezoelectric chemical sensor composed of a QCM resonator with a sensitive film measured the responses of various VOCs at different concentrations, and the obtained response sensitivities to various VOCs are shown in the attached Figure 4 shown. In particular, the sensitivity here refers to the amount of frequency change caused by a unit concentration. It is usually expressed as: S=Vf / Vc, and its unit is generally Hz / ppm or Hz / vol%. attached by Figure 4 It can be seen that the sensor of the present invention has an absolute advantage in selectivity to benzene series, and the sensitivity increases with the enhancement of the electron donating energy of the substituent on the molecular formula of the analyte.

[0039] Experimental conditions: The temperature of the detection cell is 30°C, the gas flow rate is 30-90mL / min, and the carrier gas and diluent gas used are both nitrogen.

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Abstract

The invention discloses a method for quickly determining benzene series substances in atmosphere. The method comprises the following steps: taking a hydrophobic ionic liquid material which is specifically sensitive to the benzene series substances as a sensitive coating material of a sensing element of a sensor based on mass-sensitive piezoelectric sensing technology, and obtaining the concentration of measured gas in a gas phase by detecting a frequency reduction value caused by the increase of trace mass caused by a measured object which is reversibly absorbed on a film of a resonator of the sensor. The method for determining the benzene series substances has the advantages of simple equipment structure, small volume, low cost, high sensitivity, good selectivity, quick response speed and the like, which particularly meets the need of field real-time and on-line monitoring.

Description

technical field [0001] The invention relates to a rapid detection technology of benzene series in the atmosphere, specifically a mass-based piezoelectric chemical sensor, using ionic liquids that are sensitive to benzene series as sensitive coating materials for sensor sensitive elements or resonators , to achieve continuous and real-time monitoring / detection of the measurement object through reversible physical selective adsorption / desorption. Background technique [0002] Benzene series usually refer to benzene, toluene, ethylbenzene, xylene and other substituted benzene compounds. They are colorless liquids with special aromatic odor. They are widely used in the fields of organic chemical industry, pesticide, medicine, paint and coating for home decoration, etc. Important solvent, due to its high volatility, these benzene series exist in the atmosphere in the form of vapor at room temperature; in addition, smoking, motor vehicle exhaust and various combustion processes wi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N29/028
Inventor 李海洋李安林徐秀明赵宗保李昌志
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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