CN118518745A - High-sensitivity micro-channel photoionization detector - Google Patents
High-sensitivity micro-channel photoionization detector Download PDFInfo
- Publication number
- CN118518745A CN118518745A CN202410985530.XA CN202410985530A CN118518745A CN 118518745 A CN118518745 A CN 118518745A CN 202410985530 A CN202410985530 A CN 202410985530A CN 118518745 A CN118518745 A CN 118518745A
- Authority
- CN
- China
- Prior art keywords
- electrode
- micro
- power supply
- photoionization detector
- channel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000010438 heat treatment Methods 0.000 claims abstract description 42
- 238000001514 detection method Methods 0.000 claims abstract description 33
- 230000001678 irradiating effect Effects 0.000 claims abstract description 3
- 239000007789 gas Substances 0.000 claims description 51
- 238000006243 chemical reaction Methods 0.000 claims description 13
- 230000035945 sensitivity Effects 0.000 claims description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 239000004020 conductor Substances 0.000 claims description 7
- 230000003321 amplification Effects 0.000 claims description 5
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 5
- 239000012159 carrier gas Substances 0.000 claims description 4
- 238000000034 method Methods 0.000 abstract description 12
- 238000013461 design Methods 0.000 description 10
- 239000012855 volatile organic compound Substances 0.000 description 10
- 230000008569 process Effects 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 230000004044 response Effects 0.000 description 5
- 230000009471 action Effects 0.000 description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000006870 function Effects 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 238000001824 photoionisation detection Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000004445 quantitative analysis Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 229920001940 conductive polymer Polymers 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000005669 field effect Effects 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000007306 functionalization reaction Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 239000003550 marker Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 238000004451 qualitative analysis Methods 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000011895 specific detection Methods 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
Landscapes
- Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
Abstract
The application provides a high-sensitivity micro-channel photoionization detector, which comprises: the capillary tube is used for inputting the gas to be detected; a first heating means for heating the capillary tube to a preset temperature; the electrode layer comprises a first electrode and a second electrode, and the first electrode and the second electrode are mutually spaced to form a micro-channel; the micro flow channel is connected with the capillary tube so that the gas to be detected can flow into the micro flow channel; and the light source is used for irradiating the micro-flow channel. By accurately controlling the temperature, the method realizes lower gas residue, greatly reduces the negative influence on peak shape, improves peak shape, reduces baseline height and baseline drift, and improves the accuracy of gas detection.
Description
Technical Field
The application relates to the technical field of molecular detection, in particular to a high-sensitivity micro-channel photoionization detector.
Background
The photoionization detection technology has wide application, can detect Volatile Organic Compounds (VOC) from extremely low concentration to higher concentration, is particularly applied to the accurate qualitative and quantitative analysis of VOC molecules contained in exhaled air, and can generate an exhalation map based on detection results in the field so as to carry out marker mining, thereby supporting the realization of efficient early screening, diagnosis and continuous dynamic tracking evaluation of health of diseases. However, the conventional photoionization molecular detector has problems of poor detection peak shape, baseline lifting, increased baseline drift and the like caused by VOC residues.
Disclosure of Invention
The application aims to at least solve one of the technical defects, and particularly solves the problems that the prior molecular detector has higher VOC residues, so that the detection peak shape is poor, the baseline is lifted, the baseline drift is increased and the like.
The application provides a high-sensitivity micro-channel photoionization detector, which comprises:
The capillary tube is used for inputting the gas to be detected;
A first heating means for heating the capillary tube to a preset temperature;
The electrode layer comprises a first electrode and a second electrode, and the first electrode and the second electrode are mutually spaced to form a micro-channel; the micro flow channel is connected with the capillary tube so that the gas to be detected can flow into the micro flow channel;
and the light source is used for irradiating the micro-flow channel.
In one embodiment, the high-sensitivity micro-channel photoionization detector further comprises a second heating device, wherein the second heating device is contacted with the non-electrode surface of the electrode layer and is used for heating the micro-channel to a preset temperature.
In one embodiment, the first electrode and the second electrode are MEMS devices.
In one embodiment, the high-sensitivity micro flow channel photoionization detector further comprises a protection electrode and a first power supply, wherein the protection electrode is arranged between the micro flow channels and insulated from the first electrode and the second electrode, and the first power supply is used for adjusting the potential of the protection electrode to be the same as that of the second electrode.
In one embodiment, the difference between the output voltage value of the first power supply and the first preset value is used for determining the water content of the gas to be detected; the first preset value is the output voltage value of the first power supply when the pure carrier gas passes through the micro-channel.
In one embodiment, the high-sensitivity micro-channel photoionization detector further comprises a main circuit board and an electrode layer fixing shell, wherein the electrode layer fixing shell is used for elastically pressing the electrode layer, the protection electrode and the corresponding contact terminal on the main circuit board to realize ohmic contact.
In one embodiment, the high-sensitivity micro-channel photoionization detector further comprises a light sensor, a second power supply and a control module, wherein the light sensor is used for detecting the luminous intensity of the light source, the second power supply is used for supplying power to the light source, and the control module is used for controlling the output voltage of the second power supply according to the luminous intensity so as to maintain the luminous intensity stable.
In one embodiment, the high-sensitivity micro-channel photoionization detector further comprises a light source enabling module, wherein the light source enabling module is connected between the second power supply and the light source, and the light source enabling module is controlled by the control module to turn on or off the power supply of the power supply.
In one embodiment, the high-sensitivity micro-channel photoionization detector further comprises an amplifying module, a third power supply and a control module, wherein the amplifying module is used for amplifying the detection signal output by the electrode layer, the third power supply is used for supplying power to the amplifying module, a base line of the amplifying module is set, and the control module is used for adjusting the output voltage of the third power supply according to the historical base line data.
In one embodiment, the high-sensitivity micro-channel photoionization detector further comprises an analog-to-digital conversion module, wherein the analog-to-digital conversion module is connected between the amplifying module and the control module, and is used for performing analog-to-digital conversion on the detection signal amplified by the amplifying module and outputting the detection signal to the control module.
In one embodiment, the high sensitivity microchannel photoionization detector further comprises a housing made of a conductive material.
From the above technical solutions, the embodiment of the present application has the following advantages:
The high-sensitivity micro-channel photoionization detector disclosed by the application takes the capillary as a gas input device, and the capillary is combined with the first heating device to keep the capillary at a preset temperature. The gas then enters a micro-channel formed by the electrode layers, and is ionized under the irradiation of the light source, so that corresponding electric signals can be detected on the first electrode and the second electrode of the electrode layers, and the analysis and detection of the gas to be detected can be realized. By accurately controlling the temperature, the method realizes lower gas residue, greatly reduces negative influence on peak shape, improves peak shape, reduces baseline height and baseline drift, and improves gas detection accuracy.
Drawings
In order to more clearly illustrate the embodiments of the application or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the application, and that other drawings can be obtained from these drawings without inventive faculty for a person skilled in the art.
FIG. 1 is a schematic diagram of a high-sensitivity micro-fluidic channel photoionization detector according to an embodiment of the present application;
FIG. 2 is a schematic diagram of an electrode layer according to an embodiment of the present application;
FIG. 3 is a schematic view of an electrode layer according to another embodiment of the present application;
FIG. 4 is a schematic circuit diagram of a high-sensitivity micro-fluidic channel photoionization detector according to an embodiment of the present application;
FIG. 5 is a schematic view showing the appearance of gas detection in one embodiment of the present application;
10-capillary, 20-first heating device, 30-electrode layer, 310-first electrode, 320-second electrode, 330-electrode layer contact terminal, 40-light source, 410-light source body, 420-light source window, 430-light source electrode, 50-second heating device, 60-guard electrode, 610-guard electrode connector, 620-guard electrode contact terminal, 70-electrode layer fixing case, 80-case, 810-top case, 820-bottom case.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
In the description of the embodiments of the present invention, it should be noted that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate an azimuth or a positional relationship based on that shown in the drawings, or an azimuth or a positional relationship in which the product of the present invention is conventionally put when used, it is merely for convenience of describing the present invention and simplifying the description, and it does not indicate or imply that the apparatus or element to be referred to must have a specific azimuth, be configured and operated in a specific azimuth, and thus should not be construed as limiting the present invention. Furthermore, the terms "horizontal," "vertical," "overhang" and the like, if any, do not denote a requirement that the component be absolutely horizontal or overhang, but rather may be slightly inclined. As "horizontal" merely means that its direction is more horizontal than "vertical", and does not mean that the structure must be perfectly horizontal, but may be slightly inclined. In the description of the embodiments of the present invention, "plurality" means at least 2.
The application provides a high-sensitivity micro-channel photoionization detector, referring to fig. 1, comprising a capillary tube 10, a first heating device 20, an electrode layer 30 and a light source 40.
The capillary tube 10 is a key component in a high sensitivity microchannel photoionization detector for inputting a gas to be detected. The capillary tube 10 is a tubular structure with a very small inner diameter, typically made of glass, plastic or metal. In the field of gas detection, the typical internal diameter of the capillary tube 10 ranges between tens to hundreds of micrometers. The design of the capillary 10 requires consideration of a number of factors, including the size of the inner diameter, material selection, surface treatment, etc., to ensure that the gas sample flows smoothly and that adsorption or contamination does not occur. In practical applications, the length, inner diameter and material of the capillary tube 10 may be optimized according to specific detection requirements to achieve optimal gas delivery. In general, the capillary tube 10 is used as an input device of the high-sensitivity micro-channel photoionization detector, and provides important guarantee for realizing efficient and accurate gas delivery.
The first heating means 20 is used to heat the capillary tube 10 to a preset temperature. The first heating device 20 includes a first heating unit and a first temperature sensor. The first heating element may be a wire, a film or a ceramic material that generates heat when energized. The first temperature sensor is used to monitor the temperature of the capillary tube 10 in real time, and common types include a thermistor, a thermocouple, a platinum resistor, a temperature sensitive diode, a temperature sensitive triode, and a temperature sensing IC. The control module in the high-sensitivity micro-channel photoionization detector can acquire the temperature of the capillary tube 10 by using the first temperature sensor and adjust the power of the first heating unit, so that the capillary tube 10 is heated to a preset temperature. The heating of the capillary 10 by the first heating device 20 can prevent the gas from condensing or adsorbing in the capillary 10, and ensure that the gas sample can be completely conveyed to the micro-channel region. This is particularly important for detecting low concentration or readily condensable gases. In addition, the constant temperature condition is favorable for eliminating the influence of the environmental temperature change on the detection result, and the repeatability and the reliability of measurement are improved. More importantly, by heating the capillary 10, the residue of the gas to be detected in the high-sensitivity micro-channel photoionization detector can be reduced, so that the negative influence on peak shape is reduced, the peak shape is improved, and the baseline height and baseline drift are reduced. The design of the first heating device 20 may also take into account factors such as energy consumption, uniformity of heat distribution, response speed, etc. For example, a staged heating or gradient heating approach may be employed to achieve finer temperature control.
The electrode layer 30 includes a first electrode 310 and a second electrode 320, and the first electrode 310 and the second electrode 320 are spaced apart from each other to form a micro flow channel. The micro flow channel is connected to the capillary 10 so that the gas to be detected can flow into the micro flow channel. The electrodes are typically made of a conductive material such as gold, platinum, graphite, or a conductive polymer. The design of the electrode requires consideration of a number of factors including the chemical stability of the material, electrical conductivity, interaction with the gas, etc. The micro flow channel is a fluid channel having a size in the order of micrometers to millimeters, and is connected to the capillary 10 so that the gas to be detected can flow from the capillary 10 into the channel. The design of the micro-fluidic channels has an important impact on the gas detection performance, and the small channel size can significantly reduce the amount of gas sample required, which is particularly advantageous for detecting rare or hazardous gases. The shape of the micro flow channel also has an influence on the accuracy of gas detection, and the micro flow channel can be arranged in a serpentine shape, so that the gas to be detected can be fully irradiated by the light source 40 to be ionized when passing through the micro flow channel area, and further a measurable electric signal is generated. By analysing the characteristics of these electrical signals (which may be in the form of a current signal, a converted voltage signal, etc.), at least a quantitative analysis of the gas concentration may be achieved. The design of the electrode layer 30 may also include surface modification or functionalization treatments to enhance sensitivity to particular gases. For example, the electrode layer 30 may alternatively be processed using MEMS technology.
The light source 40 is used to illuminate the micro flow channel to provide the necessary light energy for the gas detection process. The light source 40 may include a light source body 410, a light source window 420, and a light source electrode 430 therein. The light source body 410 may be selected from ultraviolet lamps, such as vacuum ultraviolet lamps. Irradiation of the microchannel by the light source 40 may initiate the photoionization process of the gas molecules. The light source window 420 is a window for transmitting light emitted from the light source body 410. The light source electrode 430 is used to connect with a corresponding power source of the light source 40 to supply power to the light source body 410. Photons generated by the light source bombard volatile organic compounds and other molecules in the gas, when the photon energy exceeds the molecular ionization energy, the molecules are ionized and broken into positively charged ions and negatively charged electrons, and the ions and the electrons collide with the polar plate under the action of an electric field of the electrode to form measurable weak ion current. The photoionization detection (PID) is based on the principle, and has high sensitivity for detecting gases such as Volatile Organic Compounds (VOCs).
The high-sensitivity micro-channel photoionization detector in this embodiment uses a capillary 10 as a gas input device, and the capillary 10 is combined with a first heating device 20 to keep the capillary 10 at a preset temperature. The gas then enters the micro flow channel formed by the electrode layer 30, and is ionized under the irradiation of the light source 40, so that corresponding electric signals can be detected on the first electrode 310 and the second electrode 320 of the electrode layer 30, and analysis and detection of the gas to be detected can be realized. By accurately controlling the temperature, the method realizes lower gas residue, greatly reduces negative influence on peak shape, improves peak shape, reduces baseline height and baseline drift, and improves gas detection accuracy.
In one embodiment, referring to fig. 1, the high-sensitivity micro-fluidic channel photoionization detector further includes a second heating device 50, where the second heating device 50 contacts the non-electrode surface of the electrode layer 30 for heating the micro-fluidic channel to a preset temperature. The non-electrode side refers to the side of the electrode layer 30 that is not conductive. The second heating device 50 provides heat to the micro flow channel by means of heat conduction. The design of the second heating device 50 generally comprises a second heating unit and a second temperature sensor. The second heating unit employs thin film resistive heating elements or micro-heaters, which may be integrated directly into the non-electrode face of electrode layer 30. The second temperature sensor is used for detecting the temperature of the micro-channel. The control module in the high-sensitivity micro-channel photoionization detector can acquire the temperature of the micro-channel by using the second temperature sensor and adjust the power of the second heating unit so as to heat the micro-channel to a preset temperature. The heating of the micro flow channel by the second heating device 50 can prevent the gas from condensing or adsorbing in the micro flow channel, so as to ensure that the gas sample can completely flow through the micro flow channel region. This is particularly important for detecting low concentration or readily condensable gases. In addition, the constant temperature condition is favorable for eliminating the influence of the environmental temperature change on the detection result, and the repeatability and the reliability of measurement are improved. More importantly, the residues of the gas to be detected in the high-sensitivity micro-channel photoionization detector can be reduced by heating the micro-channel, so that the peak shape is improved to a great extent, and the baseline height and baseline drift are reduced greatly. The design of the second heating means 50 may also take into account factors such as energy consumption, uniformity of heat distribution, response speed, etc. For example, a staged heating or gradient heating approach may be employed to achieve finer temperature control.
In one embodiment, referring to fig. 1 and 2 together, the high-sensitivity micro flow channel photoionization detector further includes a guard electrode 60 and a first power supply (not shown), wherein the guard electrode 60 is disposed between the micro flow channels and insulated from the first electrode 310 and the second electrode 320, and the first power supply is used to adjust the potential of the guard electrode 60 to be the same as the second electrode 320. The guard electrode 60 is connected to the first power source through a guard electrode connection 610 wrapped with an insulating layer. The first power supply may adjust the output voltage of the first power supply according to the potential of the second electrode 320 so that the potential of the guard electrode 60 is consistent with the second electrode 320. The design is mainly used for reducing the influence of moisture in the gas to be detected on the detection result. When the gas to be detected containing moisture flows into the micro flow channel, condensation may occur on the inner wall of the micro flow channel, resulting in a decrease in insulation degree of the material, and a leakage path is formed between the first electrode 310 and the second electrode 320, resulting in a change in baseline. The addition of the guard electrode 60 can cut off the leakage path of the first electrode 310 and the second electrode 320, and by adjusting the guard electrode 60 to be equal to the second electrode 320, the potential difference is eliminated, so that the leakage path is cut off, thereby eliminating the influence of the water-containing component on the signal. In practice, the design of the guard electrode 60 may take into account a number of factors, such as electrode material, geometry, dimensions, etc. The same or similar materials as the main electrode are typically used to ensure good electrical compatibility. The shape and size of the electrode need to be optimized according to the structure of the micro flow channel to realize the best shielding effect. A plurality of continuous small holes may be provided on the guard electrode 60 to ensure the detection effect.
In one embodiment, the difference between the output voltage value of the first power supply and the first preset value determines the moisture content of the detected gas. The first preset value is the output voltage value of the first power supply when the pure carrier gas passes through the micro-channel. It will be appreciated that the output voltage value of the first power supply will vary when the moisture contained within the microchannel is different. Therefore, the output voltage value of the first power supply can be used as a reference for the water content in the micro-channel. Specifically, the voltage value output from the first power supply when the pure carrier gas containing no water flows through the micro flow channel may be used as the reference value. And comparing the voltage value output by the current first power supply with a first preset value, and taking the difference between the voltage value and the first preset value as a judgment basis for judging whether water is contained and the water content. Specifically, a corresponding judgment logic can be added in the control module, and when the first power supply is controlled to output a corresponding voltage, the water content in the micro-channel is judged.
In one embodiment, the high-sensitivity micro-channel photoionization detector further comprises a light sensor, a second power supply and a control module, wherein the light sensor is used for detecting the luminous intensity of the light source 40, the second power supply is used for supplying power to the light source 40, and the control module is used for controlling the output voltage of the second power supply according to the luminous intensity so as to maintain the luminous intensity stable. It is understood that a light sensor is a device capable of converting an optical signal into an electrical signal. In this system, a light sensor is used to monitor the luminous intensity of the light source 40 in real time. Common types of light sensors include photodiodes, photomultipliers or CMOS image sensors, etc. Parameters such as sensitivity, response speed, spectral response range and the like of the light sensor need to be considered when the light sensor is selected so as to ensure that the change of the luminous intensity of the light source 40 can be accurately captured. The second power supply is a dedicated power supply for powering the light source 40. It can dynamically adjust the output voltage according to the control signal. When the luminous intensity of the light source 40 changes (possibly due to temperature changes, aging, etc.), the light sensor detects the change and transmits a signal to the control module. The control module compares the actual intensity with the target intensity, calculates the required adjustment, and then compensates for this variation by varying the output of the second power supply, thereby maintaining the luminous intensity of the light source 40 at a stable level.
In one embodiment, the high-sensitivity micro-channel photoionization detector further comprises a light source enabling module, wherein the light source enabling module is connected between the second power supply and the light source 40, and the light source enabling module is controlled by the control module to turn on or off the power supply of the power supply. It will be appreciated that the light source enabling module plays a critical controlling role between the second power supply and the light source 40. The main function of the module is to control the power supply state of the power supply to the light source 40 according to the instruction of the control module, so as to realize the on or off of the light source 40. The light source enabling module typically takes the form of an electronic switch, such as a Field Effect Transistor (FET), relay, or the like. Such an electronic switch enables a fast response to the control signal, enabling an accurate control of the light source 40.
In one embodiment, the high-sensitivity micro-channel photoionization detector further comprises an amplifying module, a third power supply and a control module. The amplifying module is used for amplifying the detection signal output by the electrode layer 30. In gas detection applications, the original signal is usually very weak, and the main function of the amplifying module is to amplify the weak detection signal output by the electrode layer 30 to reach the level required by the subsequent processing circuit. The amplification module typically employs a low noise, high gain operational amplifier design. The third power supply is used for supplying power to the amplifying module, and the amplifying module comprises an operational amplifier, so that the output voltage of the third power supply also determines the baseline of the signal output by the amplifying module. The control module is used for adjusting the output voltage of the third power supply according to the historical baseline data. The amplification module may have drift, resulting in a baseline shift, and by analyzing the historical data, the control module may identify and compensate for such drift trends. By maintaining a stable baseline, the system can detect even smaller changes in gas concentration.
In one embodiment, the high-sensitivity micro-channel photoionization detector further comprises a main circuit board and an electrode layer fixing shell 70, wherein the electrode layer fixing shell 70 is used for elastically pressing the first electrode 310, the second electrode 320 and the protection electrode 60 with corresponding contact terminals on the main circuit board to realize ohmic contact. It will be appreciated that the main circuit board and the electrode layer fixing case 70 are key structural components in the high-sensitivity micro flow channel photoionization detector, which together achieve electrical connection and mechanical fixation between the electrode layer 30, the guard electrode 60 and the main circuit board. The main circuit board is the core of the whole detector, integrating various electronic components and signal processing circuits. The main circuit board is provided with corresponding contact terminals corresponding to the connection points of the electrode layer 30 and the guard electrode 60. The electrode layer fixing case 70 is a specially designed mechanical structure whose main function is to firmly fix the electrode layer 30 and the guard electrode 60 to the main circuit board and to ensure that they form a reliable electrical connection with the electrode layer contact terminal 330 and the guard electrode contact terminal 620 on the circuit board. The electrode layer 30 fixing shell adopts an elastic pressing mode, so that ohmic contact is realized to replace the traditional connecting process, and the product stability, the yield and the manufacturability are improved.
In one embodiment, the main circuit board includes a circuit as shown in fig. 4, including a control module, an analog-to-digital conversion module, a digital-to-analog conversion module, a filter, an amplifying module, an electrode layer 30, a light source 40, a light sensor, a communication interface, a user interface, a first power source, a second power source, a third power source, and a fourth power source. The electrode layer 30 sequentially passes through amplification of the amplifying module and filtering of the filter, and inputs the analog detection signal to the analog-to-digital conversion module, so as to obtain a digital detection signal and input the digital detection signal to the control module. The light source 40 irradiates the micro flow channel in the electrode layer 30, so that the gas to be detected is ionized. Wherein the guard electrode 60 is controlled by a first power supply to control the voltage. The light source 40 is powered by the second power source to control the luminous intensity of the light source 40. The amplifying module is powered by a third power supply and a base line of the amplifying module is set. The first electrode 310 and the second electrode 320 in the electrode layer 30 are biased by a fourth power supply. The digital control signals of the power supplies are converted into analog control signals by the control module through the digital-to-analog conversion module, and the analog control signals are respectively input into the first power supply, the second power supply, the third power supply and the fourth power supply to control the first power supply, the second power supply, the third power supply and the fourth power supply. In addition, analog temperature signals output by the first temperature sensor and the second temperature sensor included in the temperature sensor are input into an analog-to-digital conversion module for analog-to-digital conversion to obtain digital temperature signals, and the digital temperature signals are input into the control module. The detection signals, the water content and the like obtained by the control module can be converted into communication signals through the communication conversion module and are output outwards through the user interface, and a user can obtain the VOC (volatile organic compound) spectrum by utilizing data display software through the detection signals. In addition, the memory or the processor in the control module is written with the related flow code of calibration, so that automatic calibration can be realized. The first power supply, the second power supply, the third power supply and the fourth power supply can be direct current power supplies, alternating current power supplies or alternating current-direct current combined power supplies, the amplitude and the frequency of output voltage of the first power supply, the second power supply, the third power supply and the fourth power supply are adjustable, and the two-quadrant voltage output capability (positive voltage and negative voltage) is achieved.
In one embodiment, referring to fig. 5, the high sensitivity microchannel photoionization detector further comprises a housing 80. The housing 80 may be composed of a top case 810 and a bottom case 820 to protect other structures of the high-sensitivity micro flow channel photoionization detector in the inner space of the housing. The shell is made of conductive materials, and the conductive materials can be common conductive materials or composite conductive materials, so that electromagnetic interference (EMI) outside the high-sensitivity micro-channel photoionization detector can be shielded, and the accuracy of gas detection is improved.
Finally, it is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
In the present specification, each embodiment is described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and may be combined according to needs, and the same similar parts may be referred to each other.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (11)
1. A high-sensitivity micro-channel photoionization detector, characterized by comprising the following steps:
The capillary tube is used for inputting the gas to be detected;
a first heating device for heating the capillary tube to a preset temperature;
The electrode layer comprises a first electrode and a second electrode, and the first electrode and the second electrode are mutually spaced to form a micro-channel; the micro flow channel is connected with the capillary tube so that the gas to be detected can flow into the micro flow channel;
and the light source is used for irradiating the micro-flow channel.
2. The high sensitivity microchannel photoionization detector of claim 1, further comprising a second heating device in contact with the non-electrode face of the electrode layer for heating the microchannel to the preset temperature.
3. The high sensitivity microchannel photoionization detector of claim 1, wherein the first electrode and the second electrode are MEMS devices.
4. The high-sensitivity microchannel photoionization detector of claim 1, further comprising a guard electrode disposed between the microchannels and insulated from the first and second electrodes and a first power supply for adjusting the potential of the guard electrode to be the same as the second electrode.
5. The high-sensitivity micro flow channel photoionization detector of claim 4, wherein the difference between the output voltage value of the first power supply and a first preset value is used to determine the water content of the gas to be detected; the first preset value is an output voltage value of the first power supply when pure carrier gas passes through the micro-channel.
6. The high-sensitivity micro flow channel photoionization detector of claim 4, further comprising a main circuit board and an electrode layer fixing shell, wherein the electrode layer fixing shell is used for elastically pressing the first electrode, the second electrode and the protection electrode with corresponding contact terminals on the main circuit board to realize ohmic contact.
7. The high sensitivity microchannel photoionization detector of claim 1, further comprising a light sensor for detecting the luminous intensity of the light source, a second power supply for supplying power to the light source, and a control module for controlling the output voltage of the second power supply in accordance with the luminous intensity so as to maintain the luminous intensity stable.
8. The high sensitivity microchannel photoionization detector of claim 7, further comprising a light source enabling module connected between the second power source and the light source, the light source enabling module being controlled by the control module to turn on or off power to the power source.
9. The high-sensitivity micro flow channel photoionization detector of claim 1, further comprising an amplifying module, a third power supply and a control module, wherein the amplifying module is used for amplifying the detection signal output by the electrode layer, the third power supply is used for supplying power to the amplifying module and setting a baseline of the amplifying module, and the control module is used for adjusting the output voltage of the third power supply according to the historical baseline data.
10. The high-sensitivity micro flow channel photoionization detector of claim 9, further comprising an analog-to-digital conversion module connected between the amplification module and the control module, wherein the analog-to-digital conversion module is configured to perform analog-to-digital conversion on the detection signal amplified by the amplification module and output the detection signal to the control module.
11. The high sensitivity microchannel photoionization detector of claim 1, further comprising a housing, the housing being made of a conductive material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410985530.XA CN118518745A (en) | 2024-07-23 | 2024-07-23 | High-sensitivity micro-channel photoionization detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410985530.XA CN118518745A (en) | 2024-07-23 | 2024-07-23 | High-sensitivity micro-channel photoionization detector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN118518745A true CN118518745A (en) | 2024-08-20 |
Family
ID=92285467
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410985530.XA Pending CN118518745A (en) | 2024-07-23 | 2024-07-23 | High-sensitivity micro-channel photoionization detector |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118518745A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102662018A (en) * | 2010-11-30 | 2012-09-12 | 中国科学院大连化学物理研究所 | Photo ionization detector |
| CN202974961U (en) * | 2012-12-05 | 2013-06-05 | 中国科学院大连化学物理研究所 | Photoionization detector |
| CN109884168A (en) * | 2017-12-06 | 2019-06-14 | 中国科学院大连化学物理研究所 | A kind of device and method for catalytic reaction process on-line analysis |
| US20190326108A1 (en) * | 2016-11-17 | 2019-10-24 | Micromass Uk Limited | Axial atmospheric pressure photo-ionization imaging source and inlet device |
| CN114113293A (en) * | 2021-10-28 | 2022-03-01 | 汉威科技集团股份有限公司 | Active sensitivity compensation method for photoionization detector, detector and detector |
| CN114400177A (en) * | 2022-01-28 | 2022-04-26 | 江苏谱策科学仪器有限公司 | Near-normal pressure photoionization mass spectrum device for volatile and semi-volatile compounds |
| CN117607241A (en) * | 2023-10-23 | 2024-02-27 | 深圳市计量质量检测研究院（国家高新技术计量站、国家数字电子产品质量监督检验中心） | Alpha particle ionization chamber and method for reducing radon and daughter background thereof |
-
2024
- 2024-07-23 CN CN202410985530.XA patent/CN118518745A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102662018A (en) * | 2010-11-30 | 2012-09-12 | 中国科学院大连化学物理研究所 | Photo ionization detector |
| CN202974961U (en) * | 2012-12-05 | 2013-06-05 | 中国科学院大连化学物理研究所 | Photoionization detector |
| US20190326108A1 (en) * | 2016-11-17 | 2019-10-24 | Micromass Uk Limited | Axial atmospheric pressure photo-ionization imaging source and inlet device |
| CN109884168A (en) * | 2017-12-06 | 2019-06-14 | 中国科学院大连化学物理研究所 | A kind of device and method for catalytic reaction process on-line analysis |
| CN114113293A (en) * | 2021-10-28 | 2022-03-01 | 汉威科技集团股份有限公司 | Active sensitivity compensation method for photoionization detector, detector and detector |
| CN114400177A (en) * | 2022-01-28 | 2022-04-26 | 江苏谱策科学仪器有限公司 | Near-normal pressure photoionization mass spectrum device for volatile and semi-volatile compounds |
| CN117607241A (en) * | 2023-10-23 | 2024-02-27 | 深圳市计量质量检测研究院（国家高新技术计量站、国家数字电子产品质量监督检验中心） | Alpha particle ionization chamber and method for reducing radon and daughter background thereof |
Non-Patent Citations (1)
| Title |
|---|
| 刘学 等: "用于测量ICF靶丸内氚活度的电离室的设计", 原子核物理评论, vol. 27, no. 3, 30 September 2010 (2010-09-30), pages 304 - 308 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2458375B1 (en) | Photo-ionization detectors and associated methods thereof | |
| CN101356433B (en) | Ionization-based detection | |
| US20060214580A1 (en) | Photoelectric ion source photocathode regeneration system | |
| US5677190A (en) | Cell and circuit for monitoring photochemical reactions | |
| CN111122693B (en) | Photoionization detector and method for dynamically adjusting measuring range of detector | |
| CN111587375B (en) | Thin ionization detector | |
| US10585073B2 (en) | Discharge ionization current detector | |
| US4740695A (en) | Ionization detectors for gas chromatography | |
| CN118518745A (en) | High-sensitivity micro-channel photoionization detector | |
| CN108269729B (en) | Flat plate type structure high-field asymmetric waveform ion mobility spectrometry instrument | |
| US5874314A (en) | Method for detecting organic vapors and aerosols | |
| CN108535335B (en) | Organic pollutant detection method based on multiple independent signals of same material | |
| CN105021586A (en) | Minitype DBD-AFS integrated analyzing system | |
| US20110073492A1 (en) | Voltammetric Biological Sensor | |
| RU2523765C1 (en) | Photo-ionisation detector for gas analysers | |
| US6107805A (en) | Extended detection zone in an ionization detector | |
| KR20220014327A (en) | sensor system | |
| RU174543U1 (en) | Photoionization gas detector | |
| JP5946111B2 (en) | Detection method and detection apparatus using plasma | |
| RU2455633C1 (en) | Photoionisation detector | |
| KR102539118B1 (en) | Photoionization Detector | |
| US11143619B1 (en) | Photo-ionization device with improved linearity and stability | |
| CN110793958B (en) | Hydride generation-atmospheric pressure glow discharge atomic spectrum device | |
| CN210005475U (en) | high-temperature photo-ion sensor | |
| CN116754631A (en) | Self-reference calibration structure and self-reference calibration method of PID sensor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |