CN115308183B - Optical fiber oxygen sensing system based on fluorescence quenching mechanism and coherent detection principle - Google Patents
Optical fiber oxygen sensing system based on fluorescence quenching mechanism and coherent detection principle Download PDFInfo
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- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
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- G01N21/6428—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes"
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- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
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- G01N21/645—Specially adapted constructive features of fluorimeters
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- G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
- G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
- G01N21/7703—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator using reagent-clad optical fibres or optical waveguides
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- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
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- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N21/6428—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes"
- G01N2021/6432—Quenching
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- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N21/645—Specially adapted constructive features of fluorimeters
- G01N2021/6484—Optical fibres
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- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
- G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
- G01N2021/775—Indicator and selective membrane
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
- G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
- G01N2021/7769—Measurement method of reaction-produced change in sensor
- G01N2021/7786—Fluorescence
Abstract
The invention belongs to the technical field of optical fiber sensing, and discloses an optical fiber oxygen sensing system based on a fluorescence quenching mechanism and a coherent detection principle. The optical fiber oxygen sensing probe is prepared by coating a composite film containing an oxygen sensitive fluorescent indicator on one end of an optical fiber, forming a sensing signal based on the quenching effect of oxygen on the fluorescent indicator, detecting the lag phase shift between the excitation light phase and the fluorescent phase of the fluorescent indicator based on the coherent detection principle, and directly outputting the sensing signal to be oxygen content through an intelligent terminal system processing. The invention provides a detection system for the oxygen content in gaseous and liquid environments, and the prepared optical fiber oxygen-sensitive sensing probe can be repeatedly and circularly used and has the characteristics of real-time online detection, no electromagnetic interference, high detection precision and sensitivity, good stability, nondestructive detection and the like.
Description
Technical Field
The invention belongs to the technical field of optical fiber sensing, and particularly relates to an optical fiber oxygen sensing system based on a fluorescence quenching mechanism and a coherent detection principle.
Background
At present, in the fields of cultivation, medical treatment, analytical chemistry, industry, environmental monitoring and the like, the method is very important for measuring and controlling the molecular oxygen content in a gas environment and a liquid environment.
The method is used as a basic condition for maintaining various life functions of organisms and a material basis for human survival, and has important significance for detecting oxygen. In the aquaculture industry, the death rate of aquatic products is increased and the yield is reduced due to the too low oxygen concentration; in the aspect of medical care, certain patients in special groups also need oxygen supply; in some special fields, including diving operations and exploration of outer space, oxygen is the most important energy source for life maintenance; in tissue cells, too high or too low an oxygen content can affect the normal metabolism of cells and tissues. Therefore, a rapid and accurate measurement of oxygen concentration is necessary.
The traditional dissolved oxygen measurement mainly adopts an iodine method and an oxygen electrode method. The iodine method is a classical method for measuring the dissolved oxygen, which has high measurement accuracy and good accuracy, but is a pure chemical method, has complex chemical reaction, is easily interfered by external test environment, has long measurement time and can not realize real-time online detection.
The oxygen electrode method is an electrochemical method, and is a method for measuring dissolved oxygen according to the current generated by oxidation-reduction reaction of oxygen and an electrode, so that the real-time online detection of the dissolved oxygen can be realized. The oxygen electrode is not an all-solid-state device, and is relatively large in volume, and the electrolyte and the electrode film need to be replaced frequently, so that inconvenience is brought to measurement. At present, the dissolved oxygen measuring instrument manufactured by an oxygen electrode method in the market has the common problems of low precision, poor stability, short service life, easy influence by an alternating electromagnetic field and the like.
Through the above analysis, the problems and defects existing in the prior art are as follows: the traditional oxygen concentration detection method has the defects of complex testing process, incapability of real-time online detection and short service life, large volume and easiness in electromagnetic interference of the detection electrode of the oxygen electrode method.
Disclosure of Invention
Aiming at the problems existing in the prior art, the invention provides an optical fiber oxygen sensing system based on a fluorescence quenching mechanism and a coherent detection principle. The system consists of an optical fiber oxygen sensitive sensing probe, a Y-shaped bifurcated optical fiber, a fluorescent phase detector, a temperature sensor and an intelligent terminal. The system is small in size and can be used for detecting the oxygen content in gaseous and liquid environments, and the prepared optical fiber oxygen-sensitive sensing probe can be repeatedly and circularly used and has the characteristics of real-time online detection, no electromagnetic interference, high detection precision and sensitivity, good stability, nondestructive detection and the like.
The invention is realized in such a way that a preparation method of the optical fiber oxygen-sensitive sensing probe comprises the following steps:
polishing the end face of the large-diameter optical fiber into a smooth plane or an inclined plane with a certain angle by utilizing grinding sand paper with different meshes;
soaking the polished large-diameter optical fiber in alcohol, cleaning for multiple times by using ultrasonic waves, wiping the large-diameter optical fiber clean by using dust-free paper, and naturally air-drying;
and thirdly, coating a fluorescent oxygen sensitive film containing an oxygen sensitive indicator on one end of the air-dried large-diameter optical fiber to obtain the optical fiber oxygen sensitive sensing probe.
Further, the angle of the inclined plane ranges from 0 ° to 60 °;
the coating method comprises a pulling coating method, a spin coating method, a die method, an optical fiber chemical coating method and coating by adopting a special fixture or special precision optical fiber coating equipment;
the fluorescent oxygen-sensitive film containing the oxygen-sensitive indicator consists of an oxygen-sensitive fluorescent indicator/a high molecular polymer/a solvent or an oxygen-sensitive fluorescent indicator/sol-gel;
the high molecular polymer can be any one of cellulose acetate, polymethyl methacrylate, polytetrafluoroethylene, polyvinyl chloride, polystyrene and room temperature vulcanized silicone rubber;
The solvent is acetone, N-dimethylacetamide or other solvents which can dissolve the high molecular polymer;
the oxygen-sensitive fluorescent indicator comprises: ruthenium compounds, ruthenium phenanthroline, transition metal organic complexes, polycyclic aromatic hydrocarbon organic dyes, C60 or other fluorescent indicators sensitive to oxygen.
Further, the optical fiber oxygen sensing probe is prepared by coating a composite film containing an oxygen sensitive fluorescent indicator on one end of an optical fiber, forming a sensing signal based on the quenching effect of oxygen on the fluorescent indicator, detecting a hysteresis phase shift between an excitation light phase and a fluorescent phase of the fluorescent indicator based on a coherent detection principle, and directly outputting the sensing signal to be oxygen content through an intelligent terminal system processing.
The invention further aims to provide the optical fiber oxygen-sensitive sensing probe prepared by the preparation method of the optical fiber oxygen-sensitive sensing probe.
The invention further aims to provide an optical fiber oxygen sensing system comprising the optical fiber oxygen sensing probe and based on a fluorescence quenching mechanism and a coherent detection principle, wherein the optical fiber oxygen sensing system consists of the optical fiber oxygen sensing probe, a Y-shaped bifurcated optical fiber, a fluorescence phase detector, a temperature sensor and an intelligent terminal;
The optical fiber oxygen-sensitive sensing probe is used for generating a fluorescent signal when excitation light transmitted by the Y-shaped bifurcated optical fiber irradiates the fluorescent oxygen-sensitive film;
the Y-shaped bifurcated optical fiber can be one-to-two, one-to-more or an optical fiber bundle; for transmitting excitation light; meanwhile, the fluorescent signal generated by the optical fiber oxygen-sensitive sensing probe is transmitted to a receiving end;
the fluorescence phase detector includes: a light source, a temperature sensing module, and a processor; the optical signal carrying the detection data is transmitted to the intelligent terminal;
the intelligent terminal is used for processing the optical signal into an oxygen concentration value; simultaneously, the device is used for displaying the oxygen content and the ambient temperature in the detection environment in real time;
the optical fiber oxygen-sensitive sensing probe is connected with the Y-shaped branched optical fiber single-end through an adapter and a flange; the double-end ends of the Y-shaped bifurcated optical fibers are respectively connected with a transmitting interface and a receiving interface of the fluorescent phase detector;
the fluorescent phase detector is connected with the intelligent terminal through a data line; the fluorescence phase detector is connected with the temperature sensor through a connecting wire.
Further, the fluorescence phase detector includes:
the light source can be an LED light source or a laser light source; the wavelength of the LED light source or the laser light source is selected by the optimal excitation wavelength of the oxygen-sensitive fluorescent indicator of the optical fiber oxygen-sensitive sensing probe;
The temperature sensing module is used for acquiring the ambient temperature by using the temperature sensor and adopting an external thermistor, and the probe is waterproof and can detect the liquid temperature;
the processor is used for detecting the frequency signal and the reference signal.
Another object of the present invention is to provide an optical fiber oxygen sensing method based on a fluorescence quenching mechanism and a coherent detection principle, which is applied to the optical fiber oxygen sensing system based on a fluorescence quenching mechanism and a coherent detection principle, the optical fiber oxygen sensing method based on a fluorescence quenching mechanism and a coherent detection principle comprising:
firstly, a light source emission port of a fluorescent phase detector utilizes Y-shaped bifurcated optical fibers to transmit excitation light to uniformly irradiate on a fluorescent oxygen sensitive film of an optical fiber oxygen sensing probe, and the fluorescent oxygen sensitive film generates a fluorescent signal;
and secondly, detecting lag phase shift generated between the excitation light phase and the fluorescence phase of the fluorescence indicator based on a coherent detection principle, and processing the sensing signal to obtain the oxygen content.
Further, the optical fiber oxygen sensing method based on the fluorescence quenching mechanism and the coherent detection principle comprises the following steps:
(1) Placing an optical fiber oxygen sensitive sensing probe and a temperature sensor in an environment to be detected for calibration;
(2) And measuring the ambient temperature, obtaining the linear relation between different oxygen contents and the fluorescence life by detecting the fluorescence life under different oxygen contents, and detecting the oxygen based on the calibration data and the linear relation.
It is a further object of the present invention to provide a computer device comprising a memory and a processor, the memory storing a computer program which, when executed by the processor, causes the processor to perform the steps of the optical fiber oxygen sensing method based on fluorescence quenching mechanism and coherent detection principle.
It is a further object of the present invention to provide a computer readable storage medium storing a computer program which, when executed by a processor, causes the processor to perform the steps of the optical fiber oxygen sensing method based on fluorescence quenching mechanism and coherent detection principle.
Another object of the present invention is to provide an information data processing terminal for implementing the optical fiber oxygen sensing system based on the fluorescence quenching mechanism and the coherent detection principle.
In combination with the above technical solution and the technical problems to be solved, please analyze the following aspects to provide the following advantages and positive effects:
First, aiming at the technical problems in the prior art and the difficulty in solving the problems, the technical problems solved by the technical proposal of the invention are analyzed in detail and deeply by tightly combining the technical proposal to be protected, the results and data in the research and development process, and the like, and some technical effects brought after the problems are solved have creative technical effects. The specific description is as follows:
the invention provides a method for detecting the oxygen content in gaseous and liquid environments, and the prepared optical fiber oxygen-sensitive sensing probe can be repeatedly and circularly used and has the characteristics of real-time online detection, no electromagnetic interference, high detection precision and sensitivity, good stability, nondestructive detection and the like.
Compared with the traditional classical iodometry and an oxygen electrode method, the optical fiber oxygen sensing system provided by the invention can be used for detecting the oxygen content of a liquid environment and also can be used for detecting the oxygen content of a gaseous environment; the optical fiber oxygen sensor can monitor the oxygen content in the gaseous and liquid environments in real time and can be reused. The sensor has the characteristics of higher measurement precision and sensitivity, high stability, nondestructive detection and the like, can be used for real-time repeated detection, and is quite safe and reliable.
Secondly, the technical scheme is regarded as a whole or from the perspective of products, and the technical scheme to be protected has the following technical effects and advantages:
the optical fiber oxygen sensing system constructed by the invention can monitor the oxygen content in the gaseous and liquid environments in real time and can be reused; the optical fiber probe is coated with a composite film containing oxygen sensitive substances, and the invention is based on the fluorescence quenching principle, and the substances used are ruthenium compounds. The sensor has the characteristics of higher measurement precision and sensitivity, high stability, nondestructive detection and the like, can be used for real-time repeated detection, and is quite safe.
Thirdly, as inventive supplementary evidence of the claims of the present invention, the following important aspects are also presented:
the technical scheme of the invention fills the technical blank in the domestic and foreign industries:
the invention is different from an electrochemical sensor used in the industry, an oxygen sensor based on detecting fluorescence intensity and an oxygen sensor based on lock-in amplifying equipment for detecting fluorescence life. The invention fills the technical blank that the oxygen content can be detected in both gaseous and liquid environments in domestic and foreign industries, and the oxygen content detection can be realized based on the coherent detection principle and the fluorescence detection mechanism. The sensor has the characteristics of small volume, high measurement precision, high sensitivity, high stability, nondestructive detection and the like, can be used for real-time repeated detection, and is quite safe and reliable.
The electrochemical sensor commonly used in the industry has the problems of low precision, poor stability, short service life, easiness in being influenced by an alternating electromagnetic field and the like, and the application environment is limited. Either electrochemical oxygen sensors or oxygen sensors based on the detection of fluorescence intensity can only detect oxygen levels in a single gaseous or liquid environment. In addition, the oxygen sensor for monitoring the oxygen content by detecting the fluorescence intensity is easy to be interfered by external environment and has poor stability and accuracy. The oxygen sensor for fluorescence lifetime detection based on the phase-locked amplification equipment is basically used for laboratory research due to the fact that the phase-locked amplification equipment is high in cost and large in size, and is difficult to commercialize and commonly use. The invention solves the problems well and fills the blank.
Drawings
FIG. 1 is a flow chart of a preparation method of an optical fiber oxygen sensitive sensing probe provided by an embodiment of the invention;
FIG. 2 is a schematic diagram of a gaseous ambient oxygen detection device according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a liquid environmental oxygen detection device according to an embodiment of the present invention;
FIG. 4 is a graph of sine wave fluorescence hysteresis provided by an embodiment of the present invention;
FIG. 5 is a schematic diagram of coherent detection according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of the internal structure and detection of a fluorescence phase instrument according to an embodiment of the present invention;
FIG. 7 is a chart of fluorescence intensity spectra of the optical fiber oxygen-sensitive sensing probe provided by the embodiment of the invention under different gaseous oxygen contents under excitation of a blue light LED light source;
FIG. 8 is a time sequence diagram of fluorescence intensity of the optical fiber oxygen-sensitive sensing probe provided by the embodiment of the invention under different gaseous oxygen contents under excitation of a blue light LED light source;
FIGS. 9-11 are graphs showing the phase values detected by the optical fiber oxygen-sensitive film according to the embodiment of the present invention at different oxygen contents without adding a fluorescent indicator and with adding a fluorescent indicator;
FIG. 12 is a graph showing the oxygen content versus tan. Phi. Based on the detected phase values and the Stern-Volmer equation provided by an embodiment of the present invention 0 A linear plot of/tan Φ;
FIG. 13 is a timing chart of fluorescence intensity under different oxygen contents in a liquid environment according to an embodiment of the present invention.
FIG. 14 is a timing diagram of fluorescence phases at different oxygen levels in a gaseous environment provided by an embodiment of the present invention.
FIG. 15 is a timing diagram of fluorescence phases under different oxygen contents in a liquid environment according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the following examples in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
1. The embodiments are explained. In order to fully understand how the invention may be embodied by those skilled in the art, this section is an illustrative embodiment in which the claims are presented for purposes of illustration.
As shown in fig. 1, the preparation method of the optical fiber oxygen-sensitive sensing probe provided by the embodiment of the invention comprises the following steps:
s101, grinding the end face of a large-diameter optical fiber into a smooth plane or an inclined plane with a certain angle by utilizing grinding sand paper with different meshes;
s102, soaking the polished large-diameter optical fiber in alcohol, cleaning for a plurality of times by using ultrasonic waves, wiping the large-diameter optical fiber clean by using dust-free paper, and naturally air-drying;
and S103, coating a fluorescent oxygen sensitive film containing an oxygen sensitive indicator on the air-dried end with the angle of the large-diameter optical fiber to obtain the optical fiber oxygen sensitive sensing probe.
The diameter range of the fiber core of the large-diameter optical fiber provided by the embodiment of the invention is 125-1000 um, the two end surfaces of the optical fiber are polished smoothly and flatly by using abrasive paper, the polished optical fiber is soaked in alcohol and is cleaned for many times by using ultrasonic waves, then the optical fiber is wiped clean by using dust-free paper and is naturally air-dried, and then the end surfaces of the optical fiber are observed by using a microscope to ensure that no black spots, no scratches, no breakage and the like are generated.
The angle range of the inclined plane provided by the embodiment of the invention is between 0 and 60 degrees; too small an angle gives a weak reinforcing effect and too large an angle requires particularly high requirements for the processing technology and the protection method.
The oxygen sensitive film provided by the embodiment of the invention is composed of an oxygen sensitive fluorescent indicator/a high molecular polymer/a solvent or an oxygen sensitive fluorescent indicator/sol-gel.
The oxygen-sensitive fluorescent indicator provided by the embodiment of the invention has no special requirement and can be ruthenium compound (ruthenium bipyridine (Ru (bpy) 3 Cl 2 ) Ruthenium phenanthroline, etc.), transition metal organic complexes, polycyclic aromatic hydrocarbon organic dyes, C60, etc., oxygen-sensitive fluorescent indicators.
The high molecular polymer provided by the embodiment of the invention has no special requirement, and can be cellulose acetate, polymethyl methacrylate, polytetrafluoroethylene, polyvinyl chloride, polystyrene, room temperature vulcanized silicone rubber and the like.
The solvent provided by the embodiment of the invention is matched with the used high-molecular polymer, so that the high-molecular polymer is dissolved. The solvent may be acetone if the selected high molecular polymer is cellulose acetate, and N, N dimethylacetamide if the selected high molecular polymer is polyimide.
The sol-gel method provided by the embodiment of the invention uses inorganic matters or metal alkoxides as precursors, raw materials are mixed in a solvent to obtain a uniform solution, gel with a stable three-dimensional network structure is gradually formed through hydrolytic polycondensation to lose fluidity, and then the gel is formed through a plurality of treatment methods (drying and sintering).
The present invention provides a method for researching tetraethyl orthosilicate (TEOS) as precursor 2 H 5 OH-H 2 Sol-gel of O system.
The coating method provided by the embodiment of the invention can be a lifting coating method, a spin coating method, a die method, a coating method which is carried out by adopting a special fixture and special precision optical fiber coating equipment, and an optical fiber chemical coating method.
The pulling coating method provided by the embodiment of the invention is to coat one layer of cellulose acetate film or sol-gel film coated with oxygen sensitive indicator on one end of the treated optical fiber.
The technological parameters of the pull coating method provided by the embodiment of the invention comprise: dipping speed, dipping depth, dipping time, lifting speed, lifting times and interval time.
The dipping speed is 10-200mm/min, the dipping depth is 1-10mm, the dipping time is 1-30s, the pulling speed is 10-200mm/min, and the pulling times are 1-10 times. The interval time is 1-60min. The preferred dipping speed is 100mm/min, the dipping depth is 5mm, the dipping time is 5s, the lifting speed is 10-200mm/min, the lifting times are 3 times, and the interval time is 5min.
As shown in fig. 2-3, the optical fiber oxygen sensing system based on the fluorescence quenching mechanism and the coherent detection principle provided by the embodiment of the invention consists of an optical fiber oxygen sensitive sensing probe, a Y-shaped bifurcated optical fiber, a fluorescence phase detector, a temperature sensor and an intelligent terminal.
The Y-shaped bifurcated optical fiber provided by the embodiment of the invention can be a one-to-two, one-to-many or optical fiber bundle. The preferred optical fiber bundle of the embodiment of the invention is formed by bundling a bundle of thin optical fibers, and the optical fibers are arranged together in a certain mode. The excitation light energy transmitted by the Y-shaped bifurcated optical fiber is uniformly irradiated to the fluorescent oxygen sensitive film, and meanwhile, the fluorescent signal generated by the fluorescent oxygen sensitive film can be transmitted to the receiving end through the Y-shaped bifurcated optical fiber to the greatest extent.
The fluorescence phase detector provided by the embodiment of the invention comprises: a light source, a temperature sensing module, and a processor; the signal carrying the detection data is transmitted to the intelligent terminal;
the light source provided by the embodiment of the invention can be an LED light source or a laser light source, the light source has specific emission frequency, and LED light sources or laser light sources with different colors can be adopted according to different fluorescent indicators.
The temperature sensor provided by the embodiment of the invention adopts the external thermistor to collect the ambient temperature, and can detect the liquid temperature by using the waterproof probe (when the liquid temperature is not externally connected, the liquid temperature sensor defaults to not perform temperature compensation on the measurement result).
The temperature sensor of the processor (MCU) provided by the embodiment of the invention is used for detecting the temperature of the module to ensure that the processor works at a stable temperature. The GD32F103C8T6 is selected as a processor, and a CPLD (LC 4032V) is adopted to generate a frequency signal and a reference signal in order to obtain flexible and adjustable transmission frequency.
The intelligent terminal provided by the embodiment of the invention detects the fluorescent life corresponding to different oxygen contents at a determined temperature by utilizing the autonomously programmed oxygen sensor software to determine the linear relationship, and changes the temperature to obtain the relationship between the fluorescent life corresponding to different oxygen contents at different temperatures. The detection result is more accurate. The display interface is concise and clear, and the oxygen content and the temperature change of the detected environment are displayed on line in real time. The sensor probe is changed, and the type of the sensor probe is switched at the setting interface, so that the detection of other substances can be finished, for example, the sensor probe is changed into a chloride ion probe, and the detection of chloride ions can be finished. That is, the sensing system of the present invention is not limited to use as an oxygen sensing system.
The optical fiber oxygen-sensitive sensing probe provided by the embodiment of the invention is connected with a single-end of a Y-shaped forked optical fiber through an adapter and a flange, the double-end of the Y-shaped forked optical fiber is respectively connected with a transmitting interface and a receiving interface of a fluorescence phase instrument, and a filter is arranged at the receiving interface for filtering interference of blue light. The fluorescence phase instrument is provided with an interface which is connected with a power supply and can be connected with the intelligent terminal through a data line to transmit detected data to the intelligent terminal. The software on the intelligent terminal can analyze the data and display the oxygen content and the temperature in the detection environment in real time. Before use, the calibration is needed, for example, the two-point calibration method is adopted to calibrate the oxygen content in the gas environment, the ambient temperature is measured firstly, and the fluorescent life under the anaerobic condition and the fluorescent life under the normal air condition (or the fluorescent life under the pure oxygen condition) are detected respectively to obtain the linear relation between the different oxygen content and the fluorescent life. And storing the calibration data and the linear relation for detection. The more points of different oxygen content calibrated are detected, the more accurate.
The optical fiber oxygen sensing method based on the fluorescence quenching mechanism and the coherent detection principle provided by the embodiment of the invention comprises the following steps:
firstly, a light source emission port of a fluorescent phase detector utilizes Y-shaped bifurcated optical fibers to transmit excitation light to uniformly irradiate on a fluorescent oxygen sensitive film of an optical fiber oxygen sensing probe, and the fluorescent oxygen sensitive film forms a sensing signal;
and secondly, detecting that hysteresis phase shift is generated between the excitation light phase and the fluorescence phase of the fluorescence indicator based on a coherent detection principle, and then processing the sensing signal to obtain the oxygen content.
The optical fiber oxygen sensing method based on the fluorescence quenching mechanism and the coherent detection principle provided by the embodiment of the invention comprises the following steps:
(1) Placing an optical fiber oxygen sensitive sensing probe and a temperature sensor in an environment to be detected for calibration;
(2) And measuring the ambient temperature, obtaining the linear relation between different oxygen contents and the fluorescence life by detecting the fluorescence life under different oxygen contents, and detecting the oxygen based on the calibration data and the linear relation.
The optical fiber oxygen sensing method based on the fluorescence quenching mechanism and the coherent detection principle provided by the embodiment of the invention comprises the following steps:
(1) And (3) two-point calibration, namely placing an oxygen sensitive probe and a temperature detector in a gaseous environment to be detected, selecting the gaseous environment by software, detecting the temperature of the detected environment by the temperature detector, and respectively detecting fluorescence lifetime data under the 0% oxygen-free (pure nitrogen) environment and the 20.9% oxygen content in normal atmosphere by the two-point calibration. The software processes the linear relationship and stores the data to detect the oxygen content in the environment within the calibration range.
And placing an oxygen sensitive probe and a temperature detector in a gaseous environment to be detected, selecting the gaseous environment by software, detecting the temperature of the detected environment by the temperature detector, and respectively detecting fluorescence lifetime data under the conditions of 0% of oxygen-free (pure nitrogen) environment and 100% of oxygen content by two-point calibration. The software processes to obtain a linear relationship, and the data is stored to detect the oxygen content in different environments.
(2) And (3) carrying out two-point calibration, namely placing the oxygen sensitive probe and the temperature detector in a liquid environment to be detected, selecting the liquid environment by software, detecting the temperature of the detected environment by the temperature detector, and respectively detecting fluorescence life data under the oxygen-free environment and the saturated oxygen content in the aqueous solution by selecting the two-point calibration. The software processes the linear relationship and stores the data to detect the oxygen content in the environment within the calibration range.
(3) And (3) carrying out multipoint calibration, so that the oxygen sensitive probe detects a plurality of corresponding fluorescence lifetime data under the determined oxygen content at different temperatures. For example 0%O at 25 ℃ 2 、10％O 2 、20％O 2 、30％O 2 、40％O 2 、50％O 2 、60％O 2 、70％O 2 、80％O 2 、90％O 2 、100％O 2 Fluorescence lifetime data at volume percent. A linear relationship is obtained. And replacing the fluorescent lifetime data under the environment at different temperatures, and detecting the fluorescent lifetime data under the environment again to obtain a plurality of groups of linear relations, wherein the groups of linear relations correspond to the different temperatures respectively. After calibration, the data are stored to be used for detecting the oxygen content in the environment to be detected, And displayed in real time by software.
The technical scheme of the invention is further described below with reference to specific embodiments.
Example 1
Treatment of large-diameter optical fibers:
the quartz optical fiber with the fiber core diameter of 1000 mu m is cut into small sections of 10cm, one end of the optical fiber is polished to be smooth and flat, the other end (S end) is polished to be 45-degree inclined plane, and the polishing is smooth and flat, so that no black point, no scratch and no breakage are caused on the end face of the optical fiber.
The preparation of the oxygen-sensitive sensing probe comprises the preparation of casting film liquid and the coating of an oxygen-sensitive film.
Preparing a casting solution: accurately weighing 0.3g of cellulose acetate, adding 3ml of acetone, and stirring to completely dissolve the cellulose acetate. Then 200ul of 8mg/ml ruthenium o-phenanthroline solution is added, and the mixture is sealed and stirred uniformly.
Coating of oxygen sensitive film: the technological parameters of the lifting coating are as follows: the dipping speed is 100mm/min, the dipping depth is 5mm, the dipping time is 3S, the pulling speed is 100mm/min, the interval time is 5min, the number of times of pulling is 3, and the S end of the optical fiber is immersed into the casting solution through a pulling coating machine, so that the optical fiber oxygen sensitive sensing probe is obtained.
The optical fiber oxygen sensing system for detecting the oxygen concentration is shown in fig. 2, an optical fiber oxygen sensing probe is connected with a single-end of a Y-shaped forked optical fiber through an adapter and a flange, the other two ends of the Y-shaped forked optical fiber are respectively connected with a transmitting interface and a receiving interface of a fluorescence phase instrument, and a filter plate is arranged at the receiving interface for filtering the interference of excitation light. The fluorescence phase instrument is provided with an interface which is connected with a power supply and can be connected with a computer through a data line to transmit detected data to the computer. Software on the computer can analyze the data and display the oxygen content and the temperature in the detection environment in real time. And before use, the calibration is needed, for example, the two-point calibration method is adopted to calibrate the oxygen content in the gas environment, the ambient temperature is measured firstly, and the fluorescent life under the anaerobic condition and the fluorescent life under the normal air condition (or the fluorescent life under the pure oxygen condition) are detected respectively to obtain the linear relation between the different oxygen content and the fluorescent life. And storing the calibration data and the linear relation for detection. The more points of different oxygen content calibrated are detected, the more accurate.
If the oxygen sensitive probe and the temperature detector are placed in a gaseous environment to be detected, the software selects the gaseous environment, the temperature detector detects the temperature of the detected environment, and two-point calibration is selected to respectively detect fluorescence life data under the 0% anaerobic (pure nitrogen) environment and the 100% oxygen content. FIG. 7 is a graph showing the change of fluorescence intensity signals with time under the excitation of an LED light source in a 0% oxygen-free (pure nitrogen) environment and a 100% oxygen content. FIG. 8 is a graph of fluorescence spectra of the LED light source excited and detected in a 0% oxygen-free (pure nitrogen) environment and 100% oxygen content, respectively.
Example 2
Treatment of large-diameter optical fibers:
the quartz optical fiber with the fiber core diameter of 1000 mu m is cut into small sections of 10cm, one end of the optical fiber is polished to be smooth and flat, the other end (S end) is polished to be 45-degree inclined plane, and the polishing is smooth and flat, so that no black point, no scratch and no breakage are caused on the end face of the optical fiber.
The preparation of the oxygen-sensitive sensing probe comprises the preparation of casting film liquid and the coating of an oxygen-sensitive film.
Preparing a casting solution: accurately weighing 0.3g of cellulose acetate, adding 3ml of acetone, and stirring to completely dissolve the cellulose acetate. Then 200ul of 8mg/ml ruthenium o-phenanthroline solution is added, and the mixture is sealed and stirred uniformly.
Coating of oxygen sensitive film: the technological parameters of the lifting coating are as follows: the dipping speed is 100mm/min, the dipping depth is 5mm, the dipping time is 3S, the pulling speed is 100mm/min, the interval time is 5min, the number of times of pulling is 3, and the S end of the optical fiber is immersed into the casting solution through a pulling coating machine, so that the optical fiber oxygen sensitive sensing probe is obtained.
The optical fiber oxygen sensing system for detecting the oxygen concentration is shown in fig. 2, an optical fiber oxygen sensing probe is connected with a single-end of a Y-shaped forked optical fiber through an adapter and a flange, the other two ends of the Y-shaped forked optical fiber are respectively connected with a transmitting interface and a receiving interface of a fluorescence phase instrument, and a filter plate is arranged at the receiving interface for filtering the interference of excitation light. The fluorescence phase instrument is provided with an interface which is connected with a power supply and can be connected with a computer through a data line to transmit detected data to the computer. Software on the computer can analyze the data and display the oxygen content and the temperature in the detection environment in real time. And before use, the calibration is needed, for example, the two-point calibration method is adopted to calibrate the oxygen content in the gas environment, the ambient temperature is measured firstly, and the fluorescent life under the anaerobic condition and the fluorescent life under the normal air condition (or the fluorescent life under the pure oxygen condition) are detected respectively to obtain the linear relation between the different oxygen content and the fluorescent life. And storing the calibration data and the linear relation for detection. The more points of different oxygen content calibrated are detected, the more accurate.
If the oxygen sensitive probe and the temperature detector are placed in a gaseous environment to be detected, the software selects the gaseous environment, the temperature detector detects the temperature of the detected environment, and two-point calibration is selected to respectively detect fluorescence life data under the 0% anaerobic (pure nitrogen) environment and the 100% oxygen content. FIG. 7 is a graph showing the change of fluorescence intensity signals with time under the excitation of an LED light source in a 0% oxygen-free (pure nitrogen) environment and a 100% oxygen content. FIG. 8 is a graph of fluorescence spectra of the LED light source excited and detected in a 0% oxygen-free (pure nitrogen) environment and 100% oxygen content, respectively.
The phase values of the blank film to which the oxygen indicator is not added and the phase values of the oxygen sensitive film to which the oxygen indicator is added at different oxygen contents are detected as shown in fig. 9 to 11. FIG. 12 shows the oxygen content versus tan. Phi. Based on the detected phase values and the Stern-Volmer equation 0 Linear dependence of/tan phi.
Example 3
Treatment of large-diameter optical fibers:
the quartz optical fiber with the fiber core diameter of 1000 mu m is cut into small sections of 10cm, one end of the optical fiber is polished to be smooth and flat, the other end (S end) is polished to be 45-degree inclined plane, and the polishing is smooth and flat, so that no black point, no scratch and no breakage are caused on the end face of the optical fiber.
The preparation of the oxygen-sensitive sensing probe comprises the preparation of casting film liquid and the coating of an oxygen-sensitive film.
Preparing a casting solution: 685 mu L of tetraethyl orthosilicate, 1095 mu L of absolute ethyl alcohol, 220 mu L0.01M of HCl, 211 mu L of 8mg/mL ruthenium phenanthroline solution and 420 mu L of formamide are respectively measured in a 7mL penicillin bottle, are sealed by a preservative film, are vigorously stirred for 24 hours, and are then left stand for 2 days.
Coating of oxygen sensitive film: the technological parameters of the lifting coating are as follows: the dipping speed is 100mm/min, the dipping depth is 5mm, the dipping time is 3S, the pulling speed is 100mm/min, the interval time is 5min, the number of times of pulling is 10, the S end of the optical fiber is immersed into sol-gel film casting liquid through a pulling film plating machine, and the optical fiber is placed in a refrigerator at 4 ℃ for standing until the end face of the optical fiber is completely formed.
The optical fiber oxygen sensing system for detecting the oxygen concentration is shown in fig. 3, an optical fiber oxygen sensing probe is connected with a single-end of a Y-shaped forked optical fiber through an adapter and a flange, the other two ends of the Y-shaped forked optical fiber are respectively connected with a transmitting interface and a receiving interface of a fluorescence phase instrument, and a filter plate is arranged at the receiving interface for filtering the interference of excitation light. The fluorescence phase instrument is provided with an interface which is connected with a power supply and can be connected with a computer through a data line to transmit detected data to the computer. Software on the computer can analyze the data and display the oxygen content and the temperature in the detection environment in real time. Before use, the calibration is needed, for example, a two-point calibration method is adopted to calibrate the oxygen content in the liquid environment, the ambient temperature is measured firstly, and the fluorescence lifetime under the anaerobic aqueous solution and the saturated oxygen aqueous solution is detected respectively to obtain the linear relation between different oxygen contents and the fluorescence lifetime. And storing the calibration data and the linear relation for detection. The more points of different oxygen content calibrated the more accurate the detection. The oxygen sensor calibration principle is the same whether it is in a liquid or gaseous environment.
The change of the fluorescence intensity signal of the oxygen sensitive probe with time under the oxygen-free water solution and the saturated oxygen water solution is detected by using the LED light source excitation, and the graph is shown in figure 13.
Example 4
Treatment of large-diameter optical fibers:
the quartz optical fiber with the fiber core diameter of 1000 mu m is cut into small sections of 10cm, one end of the optical fiber is polished to be smooth and flat, the other end (S end) is polished to be 45-degree inclined plane, and the polishing is smooth and flat, so that no black point, no scratch and no breakage are caused on the end face of the optical fiber.
The preparation of the oxygen-sensitive sensing probe comprises the preparation of casting film liquid and the coating of an oxygen-sensitive film.
Preparing a casting solution: 685 mu L of tetraethyl orthosilicate, 1095 mu L of absolute ethyl alcohol, 220 mu L0.01M of HCl, 211 mu L of 8mg/mL ruthenium phenanthroline solution and 420 mu L of formamide are respectively measured in a 7mL penicillin bottle, are sealed by a preservative film, are vigorously stirred for 24 hours, and are then left stand for 2 days.
Coating of oxygen sensitive film: the technological parameters of the lifting coating are as follows: the dipping speed is 100mm/min, the dipping depth is 5mm, the dipping time is 3S, the pulling speed is 100mm/min, the interval time is 5min, the number of times of pulling is 10, the S end of the optical fiber is immersed into sol-gel film casting liquid through a pulling film plating machine, and the optical fiber is placed in a refrigerator at 4 ℃ for standing until the end face of the optical fiber is completely formed.
The optical fiber oxygen sensing system for detecting the oxygen concentration is shown in fig. 2, an optical fiber oxygen sensing probe is connected with a single-end of a Y-shaped forked optical fiber through an adapter and a flange, the other two ends of the Y-shaped forked optical fiber are respectively connected with a transmitting interface and a receiving interface of a fluorescence phase instrument, and a filter plate is arranged at the receiving interface for filtering the interference of excitation light. The fluorescence phase instrument is provided with an interface which is connected with a power supply and can be connected with a computer through a data line to transmit detected data to the computer. Software on the computer can analyze the data and display the oxygen content and the temperature in the detection environment in real time. Before use, the calibration is needed, for example, a two-point calibration method is adopted to calibrate the oxygen content in the liquid environment, the ambient temperature is measured first, and the fluorescence lifetime under pure nitrogen and pure oxygen environments is detected respectively to obtain the linear relation between different oxygen contents and fluorescence lifetime. And storing the calibration data and the linear relation for detection. The more points of different oxygen content calibrated the more accurate the detection. The oxygen sensor calibration principle is the same whether it is in a liquid or gaseous environment.
The change patterns of the fluorescence phases of the oxygen sensitive probe with time under the pure nitrogen and the pure oxygen in the gaseous environment are respectively detected by using the LED light source excitation, and are shown in figure 14.
Example 5
Treatment of large-diameter optical fibers:
the quartz optical fiber with the fiber core diameter of 1000 mu m is cut into small sections of 10cm, one end of the optical fiber is polished to be smooth and flat, the other end (S end) is polished to be 45-degree inclined plane, and the polishing is smooth and flat, so that no black point, no scratch and no breakage are caused on the end face of the optical fiber.
The preparation of the oxygen-sensitive sensing probe comprises the preparation of casting film liquid and the coating of an oxygen-sensitive film.
Preparing a casting solution: 685 mu L of tetraethyl orthosilicate, 1095 mu L of absolute ethyl alcohol, 220 mu L0.01M of HCl, 211 mu L of 8mg/mL ruthenium phenanthroline solution and 420 mu L of formamide are respectively measured in a 7mL penicillin bottle, are sealed by a preservative film, are vigorously stirred for 24 hours, and are then left stand for 2 days.
Coating of oxygen sensitive film: the technological parameters of the lifting coating are as follows: the dipping speed is 100mm/min, the dipping depth is 5mm, the dipping time is 3S, the pulling speed is 100mm/min, the interval time is 5min, the number of times of pulling is 10, the S end of the optical fiber is immersed into sol-gel film casting liquid through a pulling film plating machine, and the optical fiber is placed in a refrigerator at 4 ℃ for standing until the end face of the optical fiber is completely formed.
The optical fiber oxygen sensing system for detecting the oxygen concentration is shown in fig. 3, an optical fiber oxygen sensing probe is connected with a single-end of a Y-shaped forked optical fiber through an adapter and a flange, the other two ends of the Y-shaped forked optical fiber are respectively connected with a transmitting interface and a receiving interface of a fluorescence phase instrument, and a filter plate is arranged at the receiving interface for filtering the interference of excitation light. The fluorescence phase instrument is provided with an interface which is connected with a power supply and can be connected with a computer through a data line to transmit detected data to the computer. Software on the computer can analyze the data and display the oxygen content and the temperature in the detection environment in real time. Before use, the calibration is needed, for example, a two-point calibration method is adopted to calibrate the oxygen content in the liquid environment, the ambient temperature is measured firstly, and the fluorescence lifetime under the anaerobic aqueous solution and the saturated oxygen aqueous solution is detected respectively to obtain the linear relation between different oxygen contents and the fluorescence lifetime. And storing the calibration data and the linear relation for detection. The more points of different oxygen content calibrated the more accurate the detection. The oxygen sensor calibration principle is the same whether it is in a liquid or gaseous environment.
The change of the fluorescence phase of the oxygen sensitive probe with time under the condition of the anaerobic water solution and the saturated oxygen water solution is detected by using the LED light source excitation, and the graph is shown in figure 15.
2. Application example. In order to prove the inventive and technical value of the technical solution of the present invention, this section is an application example on specific products or related technologies of the claim technical solution.
The optical fiber sensing method based on the fluorescence quenching mechanism and the coherent detection principle provided by the embodiment of the invention can also be applied to the detection of chloridion or other substances except oxygen.
It should be noted that the embodiments of the present invention can be realized in hardware, software, or a combination of software and hardware. The hardware portion may be implemented using dedicated logic; the software portions may be stored in a memory and executed by a suitable instruction execution system, such as a microprocessor or special purpose design hardware. Those of ordinary skill in the art will appreciate that the apparatus and methods described above may be implemented using computer executable instructions and/or embodied in processor control code, such as provided on a carrier medium such as a magnetic disk, CD or DVD-ROM, a programmable memory such as read only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The device of the present invention and its modules may be implemented by hardware circuitry, such as very large scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., as well as software executed by various types of processors, or by a combination of the above hardware circuitry and software, such as firmware.
3. Evidence of the effect of the examples. The embodiment of the invention has a great advantage in the research and development or use process, and has the following description in combination with data, charts and the like of the test process.
The optical fiber oxygen sensor constructed by the invention can be suitable for measuring gaseous oxygen and dissolved oxygen, can effectively solve the problems, and can realize real-time online detection and long-distance remote control monitoring.
The optical fiber oxygen sensor constructed by the invention detects the oxygen concentration by a dynamic quenching principle of fluorescence. Fluorescence quenching can change the fluorescence intensity and fluorescence lifetime, and thus detection methods can be divided into two categories: a fluorescence radiation intensity detection method based on a change in fluorescence intensity and a fluorescence radiation lifetime detection method based on a change in fluorescence lifetime. Wherein the fluorescence radiation can be described by the Stern-Volmer equation:
Ι 0 /Ι＝τ 0 /τ＝1+K[Q]
I 0 、I、τ 0 τ is the fluorescence intensity and lifetime under oxygen-free and oxygen-containing conditions, [ Q ]]K is a Stern-Volmer constant, which is fixed for a particular quencher, for the concentration of oxygen. From this equation, it can be seen that the concentration information of the analyte can be obtained regardless of the fluorescence intensity or fluorescence lifetime. Because the fluorescence intensity of the substance is easily influenced by external factors, and the fluorescence lifetime value of the fluorescence indicator is an intrinsic parameter of the fluorescent substance, the fluorescence lifetime detection is not influenced by the change of the external factors, and the fluorescent indicator has excellent anti-interference capability.
The optical fiber oxygen sensor constructed by the invention detects the phase by using the coherent detection principle so as to reflect the service life of fluorescence, an excitation light source used by a phase shift method is modulated in a sine way, and the fluorescence correspondingly generated also has a sine change rule, as shown in fig. 4:
i.e. at a certain frequency, the phase of the excitation light
And fluorescent phase of fluorescent indicator +.>
Hysteresis phase shift is generated between the fluorescent lamp and the fluorescent lamp, and the hysteresis phase shift amount and the fluorescent lamp life are in corresponding relation. Thus, detection of fluorescence lifetime can be achieved by measuring the hysteresis phase shift between excitation light and fluorescence of the fluorescent indicator.
Fluorescence has a lag phase shift Φ with respect to the modulated light, this lag phase shift Φ being related to fluorescence lifetime τ: tan phi = ωτ;
where ω is the angular velocity of the sinusoidal modulated signal, ω=2pi f. The sinusoidal modulation signal frequency f is typically selected between 1 and 200 kHz.
The present invention detects the required phase signal by the coherent detection principle, which is shown in fig. 5 below.
Assuming the fluorescence signal before entering the multiplier
(for simplicity, the high frequency components and noise are ignored, in fact the fluorescence signal contains relatively large noise and high frequency components), A represents the amplitude of the fluorescence signal, < > >
Representing the phase of the fluorescent signal. While the frequency generator generates two reference signals of the same frequency as the fluorescent signal,
and->
(the two co-frequency reference signals are equal in amplitude, 90 DEG out of phase and are generated by the same hardware link, staggered in time domain, i.e. signaled first +.>
Enters a multiplier to finish the sampling of the ADC and then is added with ∈>
And (5) entering a multiplier and then performing ADC sampling. This can maximize the detection accuracy. )
As can be seen from equation 1 in fig. 5, the direct current component is generated after passing through the multiplier
And high frequency component->
The high-frequency component is filtered by a low-pass filter to obtain a direct-current component
The ADC sampling can be performed directly (in practice, the high frequency or noise components in the fluorescent signal become high frequency components after passing through the multiplier). A in the direct current component 1 And->
For the amplitude and phase of the reference signal, the known parameters are fixed, in order to determine A and +.>
A reference signal +.>
From equations 2 and 3, A can be found, and after A is obtained, the mixture is brought back into +.>
Can obtain +.>
The sampling coherent detection has the advantages that very weak signals can be detected, and the smaller the bandwidth of the low-pass filter is, the stronger the anti-interference capability of the detection system on noise is.
Similarly, no matter what kind of substance is detected, only a fluorescent indicator sensitive to the substance needs to be found, so that a fluorescence quenching phenomenon exists, the detection of the fluorescence service life under different contents can be realized through the principle, and the real-time on-line monitoring of the substance can be realized through data processing. Namely, the invention can also be applied to the detection of chloride ions or other substances besides oxygen.
The foregoing is merely illustrative of specific embodiments of the present invention, and the scope of the invention is not limited thereto, but any modifications, equivalents, improvements and alternatives falling within the spirit and principles of the present invention will be apparent to those skilled in the art within the scope of the present invention.
Claims (9)
1. The preparation method of the optical fiber oxygen-sensitive sensing probe is characterized by comprising the following steps of:
polishing the end face of the large-diameter optical fiber into a smooth plane or an inclined plane with a certain angle by utilizing grinding sand paper with different meshes;
soaking the polished large-diameter optical fiber in alcohol, cleaning for multiple times by using ultrasonic waves, wiping the large-diameter optical fiber clean by using dust-free paper, and naturally air-drying;
Coating a fluorescent oxygen sensitive film containing an oxygen sensitive indicator on one end of the air-dried large-diameter optical fiber to obtain an optical fiber oxygen sensitive sensing probe;
the optical fiber oxygen sensing probe is prepared by coating a composite film containing an oxygen sensitive fluorescent indicator on one end of an optical fiber, forming a sensing signal based on the quenching effect of oxygen on the fluorescent indicator, detecting lag phase shift between an excitation light phase and a fluorescent phase of the fluorescent indicator based on a coherent detection principle, and directly outputting the sensing signal to be oxygen content through an intelligent terminal system processing.
2. The method of manufacturing an optical fiber oxygen sensing probe according to claim 1, wherein the angle of the inclined plane ranges from 0 ° to 60 °; the diameter range of the fiber core of the large-diameter optical fiber is 125-1000 um;
the coating method comprises a pulling coating method, a spin coating method, a die method, a coating method by adopting a special fixture or special precision optical fiber coating equipment, and an optical fiber chemical coating method;
the fluorescent oxygen-sensitive film containing the oxygen-sensitive indicator consists of an oxygen-sensitive fluorescent indicator/a high molecular polymer/a solvent or an oxygen-sensitive fluorescent indicator/sol-gel;
the high molecular polymer can be any one of cellulose acetate, polymethyl methacrylate, polytetrafluoroethylene, polyvinyl chloride, polystyrene and room temperature vulcanized silicone rubber;
The solvent is acetone, N-dimethylacetamide or other solvents which can dissolve the high molecular polymer;
the oxygen-sensitive fluorescent indicator comprises: ruthenium compounds, ruthenium phenanthroline, transition metal organic complexes, polycyclic aromatic hydrocarbon organic dyes, C60 or other fluorescent indicators sensitive to oxygen.
3. An optical fiber oxygen-sensitive sensing probe prepared by the method for preparing an optical fiber oxygen-sensitive sensing probe according to any one of claims 1 to 2.
4. An optical fiber oxygen sensing system based on a fluorescence quenching mechanism and a coherent detection principle and comprising the optical fiber oxygen sensing probe according to claim 3, wherein the optical fiber oxygen sensing system based on the fluorescence quenching mechanism and the coherent detection principle consists of the optical fiber oxygen sensing probe, a Y-shaped bifurcated optical fiber, a fluorescence phase detector, a temperature sensor and an intelligent terminal;
the optical fiber oxygen-sensitive sensing probe is used for generating a fluorescent signal when excitation light emitted by the Y-shaped bifurcated optical fiber irradiates the fluorescent oxygen-sensitive film;
the Y-shaped bifurcated optical fiber can be one-to-two, one-to-more or an optical fiber bundle; for transmitting excitation light; meanwhile, the fluorescent signal generated by the optical fiber oxygen-sensitive sensing probe is transmitted to a receiving end;
The fluorescence phase detector includes: a light source, a temperature sensing module, and a processor; the optical signal carrying the detection data is transmitted to the intelligent terminal;
the intelligent terminal is used for processing the optical signal into an oxygen concentration value; simultaneously, the device is used for displaying the oxygen content and the ambient temperature in the detection environment in real time;
the optical fiber oxygen-sensitive sensing probe is connected with the Y-shaped branched optical fiber single-end through an adapter and a flange; the double-end ends of the Y-shaped bifurcated optical fibers are respectively connected with a transmitting interface and a receiving interface of the fluorescent phase detector;
the fluorescent phase detector is connected with the intelligent terminal through a data line; the fluorescence phase detector is connected with the temperature sensor through a connecting wire.
5. The fiber optic oxygen sensing system based on fluorescence quenching mechanism and coherent detection principle according to claim 4, wherein the fluorescence phase detector comprises:
the light source can be an LED light source or a laser light source; the light source has specific emission frequency, and LED light sources or laser light sources with different colors can be adopted according to different fluorescent indicators;
the temperature sensing module is used for acquiring the ambient temperature by using the temperature sensor and adopting an external thermistor, and detecting the liquid temperature by using a waterproof probe;
The processor is used for detecting the frequency signal and the reference signal.
6. An optical fiber oxygen sensing method based on a fluorescence quenching mechanism and a coherent detection principle applied to the optical fiber oxygen sensing system based on a fluorescence quenching mechanism and a coherent detection principle according to any one of claims 4 to 5, characterized in that the optical fiber oxygen sensing method based on a fluorescence quenching mechanism and a coherent detection principle comprises:
firstly, utilizing a light source emission port of a fluorescence phase detector to transmit excitation light by utilizing a Y-shaped bifurcated optical fiber to uniformly irradiate on a fluorescence oxygen sensitive film of an optical fiber oxygen sensing probe, wherein the fluorescence oxygen sensitive film forms a sensing signal;
and secondly, detecting that hysteresis phase shift is generated between the excitation light phase and the fluorescence phase of the fluorescence indicator based on a coherent detection principle, and then processing the sensing signal to obtain the oxygen content.
7. The optical fiber oxygen sensing method based on the fluorescence quenching mechanism and the coherent detection principle according to claim 6, wherein the optical fiber oxygen sensing method based on the fluorescence quenching mechanism and the coherent detection principle comprises the steps of:
(1) Placing an optical fiber oxygen sensitive sensing probe and a temperature sensor in an environment to be detected for calibration;
(2) And measuring the ambient temperature, obtaining the linear relation between different oxygen contents and the fluorescence life by detecting the fluorescence life under different oxygen contents, and detecting the oxygen based on the calibration data and the linear relation.
8. A computer device comprising a memory and a processor, the memory storing a computer program which, when executed by the processor, causes the processor to perform the steps of the optical fiber oxygen sensing method based on fluorescence quenching mechanism and coherent detection principle as claimed in any one of claims 5-6.
9. An information data processing terminal, characterized in that the information data processing terminal is used for realizing the optical fiber oxygen sensing system based on the fluorescence quenching mechanism and the coherent detection principle as claimed in any one of claims 1-2.
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