VOCs detection sensing system and detection method

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VOCs (Volatile Organic Compounds: Volatile Organic Compounds) are common pollutants in the environment. Many types of VOCs have certain toxicity and irritation. When they reach a certain concentration, they will have a huge impact on human health. For the "invisible killer" of mankind.

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Most of the testing for VOCs is carried out in the air environment, but in some cases, we need to test for VOCs in liquids, especially water. For example, the food safety sector needs to detect pesticide residues such as organochlorine and organophosphorus in liquid samples, and the aquaculture industry needs to monitor the concentration of organic nitrogen in ponds.

However, the current analysis and detection methods for VOCs in liquid environments often use large analytical instruments such as gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS), or use expensive and complex detectors such as photoionization detectors ( PhotoIonizationDetector, PID for short), the above detection method is not convenient for on-site analysis and large-scale application due to the large size of the detection equipment.

The mass-sensitive microsensor is a new type of detection technology developed in recent years. Its working principle is: by fixing sensitive materials on the surface of the sensor, when the detection process, the molecules of the analyte are specifically adsorbed to these sensitive materials It will cause the frequency change of the sensor device, and this frequency change is generally proportional to the concentration of the analyte within the sensor range. Therefore, the pre-calibrated sensor can obtain the concentration of the target analyte in the environment through frequency changes. This type of sensor has been used in many applications in gas detection, and has demonstrated extremely high resolution and fast response capabilities, and is especially suitable for portable on-site trace material detection. However, when the object to be measured is liquid, the application of this type of sensor faces great difficulties. This is because the damping of liquid is much greater than that of gas, so it is difficult for this type of sensor to be excited to resonate in a liquid environment and the mass sensitivity is greatly reduced.

In view of this, it is necessary to design a new sensing system and detection method for VOCs detection.

【Recommended invention】

"A sensing system and detection method for VOCs detection"

[Summary of the invention]

The present invention proposes a sensing system and a detection method for VOCs detection, which are used to solve the problem that the detection equipment used for VOCs in a liquid environment in the prior art is too large and inconvenient for on-site analysis; and a portable quality-sensitive type When the micro sensor is used for the detection of VOCs in a liquid environment, it is difficult to vibrate and the mass sensitivity is greatly reduced.

In order to achieve the above objectives and other related objectives, the sensing system of the present invention is shown in the following figure, including:

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The upper part of the sampling pool is equipped with a sample inlet; the detection pool, including the sample room, the sensor room, and the waterproof and breathable membrane separating the sample room and the sensor room; the quality-sensitive micro sensor fixed in the sensor room; located outside the detection pool, and The signal processing circuit and the display device that are electrically connected to the quality-sensitive micro sensor; the pipeline connecting the sample injection pool and the sample chamber; and the liquid pump located on the pipeline.

During detection, the sample chamber is used to place the VOCs solution to be tested, the sensor chamber is used to place the quality-sensitive microsensors, and the waterproof and breathable film is used to isolate the sample chamber and the sensor chamber, so that the VOCs solution to be tested in the sample chamber cannot enter the sensor chamber. However, the gas molecules volatilized from the VOCs solution to be tested can pass through the waterproof and breathable membrane, enter the sensor room, and be detected by the mass-sensitive microsensor, so that the mass-sensitive microsensor does not need to be in contact with the VOCs solution to be tested. Detection of VOCs solution.

The advantages of the VOCs detection sensing system and detection method include: the sensing system is composed of a portable mass-sensitive micro sensor, which is small in size and light in weight, which is convenient for on-site analysis; and the sample containing the sample to be tested is replaced by a waterproof and breathable membrane. The chamber is separated from the sensor chamber where the mass-sensitive microsensor is placed, so that the VOCs solution sample to be tested cannot reach the mass-sensitive microsensor, but the volatilized gas molecules can enter the sensor chamber through the waterproof and breathable membrane. The micro sensor detects it, so that the mass-sensitive micro sensor can be used for the detection of VOCs solution.