Quartz crystal resonator, preparation and application thereof

A quartz crystal and resonator technology, applied in the field of quartz crystal resonators, achieves the effects of fast response, high sensitivity and simple production

Inactive Publication Date: 2009-04-01
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

High accuracy, good reliability and no complicated sample preparation process

Method used

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  • Quartz crystal resonator, preparation and application thereof
  • Quartz crystal resonator, preparation and application thereof
  • Quartz crystal resonator, preparation and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] A. Take the quartz crystal oscillator and soak it in absolute ethanol, ultrasonically clean it for 3 minutes, dry it, measure the fundamental frequency with QCM, and record the precise frequency value f 0 =9992120Hz, package the chip for use;

[0043] B. Accurately weigh 70mg of ionic liquid [C 4 MIm]Cl, dissolved in 7mL of chloroform, prepared as a 10mg / mL coating solution.

[0044] C. Suspend the cleaned 9992120Hz quartz crystal oscillator in 10mg / mL ionic liquid [C 4 MIm]Cl in a chloroform solution for 30 sec, until the volatile organic solvent chloroform on the surface of the wafer is volatilized.

[0045] D. Purge the coated quartz crystal oscillator at 60°C with 60mL / min of high-purity nitrogen, the frequency is stable for 1-2 hours, and the frequency f is measured on the QCM 1 =9987750Hz, then the frequency reduction value |Δf|=|f 1 -f 0 |=|9987550Hz-9992120Hz|=4550Hz is the decrease in oscillation frequency caused by a slight increase in wafer quality cause...

Embodiment 2

[0049] Use the ionic liquid prepared in embodiment 1 [C 4 MIm]Cl is a QCM oscillator with sensitive membrane material, and the response sensitivities to dichloromethane (DCM), ethanol (ethanol), acetone (acetone), toluene (toluene) and benzene (benzene) were measured respectively, as shown in the attached image 3 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 image 3 It can be seen that the ethanol sensor of the present invention has an absolute advantage in selectivity to ethanol gas and is basically free from interference from other organic pollutants.

[0050] Test conditions: The temperature of the detection cell is 30°C, the gas flow rate is 120mL / min, and the carrier gas and diluent gas used are both nitrogen.

Embodiment 3

[0052] Use coated ionic liquid [C in embodiment 1 4 MIm]Cl is a QCM oscillator with sensitive membrane material, and the frequency response value of the sensor is measured for 70-2500ppm ethanol gas, and the relationship curve between frequency change and concentration is made, as shown in the attached Figure 4 As shown, the two form a good linear relationship (R 2 =0.9992), therefore, by measuring the frequency change value caused by a certain concentration of ethanol gas on the QCM ethanol sensor, and substituting it into the frequency-concentration relationship equation C=15.0|Δf|+29.8, the concentration value of the measured gas can be obtained, The unit is ppm.

[0053] Test conditions: The temperature of the detection cell is 30°C, the gas flow rate is 50-150mL / min, and the carrier gas and diluent gas used are both nitrogen.

[0054] For example, the measurement process of 709ppm ethanol gas is as attached Figure 5 As shown, the measurement conditions: the temperatu...

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Abstract

The invention relates to a gas sensor, in particular to a quartz crystal resonator which is sensitive to ethanol, and preparation and application thereof, comprising an AT-cut quartz wafer and a gold electrode fixed on the quartz wafer, wherein, the outer surface of the gold electrode and/or the quartz wafer is coated with an ionic liquid membrane. The resonator is applied to a conventional QCM sensor to prepare a QCM ethanol gas sensor, and the operation principle is the quartz crystal microbalance technology; the response frequency of the sensor is reduced with the fractional increase of the surface quality of the resonator caused by the absorption of the ethanol gas on the surface of a sensitive membrane of the quartz resonator, and the reduced value of the frequency and the concentration of the ethanol gas are linear. The gas sensor has the advantages of simple structure, small size, fast and real-time response, high sensitivity, good selectivity, no need of analog to digital conversion for the output of frequency signals, convenient batch production and the like, and is particularly suitable for measuring the concentration of the ethanol gas in the air in real time.

Description

technical field [0001] The invention relates to a gas sensor, in particular to an ethanol-sensitive quartz crystal resonator and its preparation and application. Background technique [0002] In the field of gas sensor technology, exploring new sensor materials with high sensitivity, good selectivity and high stability, and making new sensors have always been the goals pursued by people. [0003] At present, the main technologies for ethanol gas detection include gas chromatography, optical fiber sensing technology, semiconductor sensing technology, electrochemical sensor technology, and spectrophotometry. Among these technologies, most of them are based on the principle of semiconductor sensors and rely on The action of metals, transition metal oxides (or mixed with certain dopants or catalysts) and ethanol gas molecules, the working temperature is high, generally at 200 ° C ~ 300 ° C (published Chinese patent applications 200310109270.8 and 200610010822.3), and the sensor ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N27/00
Inventor 李海洋徐秀明赵宗保李昌志李安林李京华初建胜
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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