Disinfectant fluid by-product detection device based on incoherent correlation digital holography

Abstract

The invention discloses a device for detecting disinfection by-products in drinking water based on incoherent correlation digital holography, and belongs to the technical field of disinfection by-product detection. The detection device comprises a light source, an optical splitter, an optical filter, a lens, a spatial light modulator and a CCD camera. The LED light source emits green light to irradiate a water body to be detected to excite the fluorescent probe, yellow fluorescent light reflected from the water body passes through the optical filter and the lens and then reaches the spatial light modulator, light waves emitted by the same object point are divided into two beams for interference, and formed interference fringes are recorded on the CCD. Recording of the hologram is achieved through incoherent superposition of all the point source holograms, and information such as three-dimensional distribution of an object can be obtained through subsequent reconstruction of a computer. The detection device provided by the invention can realize nondestructive detection, is simple and practical, obtains three-dimensional information in combination with a holographic technology, and is beneficial to deeper research on disinfection by-products.

Description

Technical Field

[0001] The present invention belongs to the technical field of disinfection by-product detection, and in particular relates to a disinfection by-product detection device in drinking water based on incoherent correlation digital holography. Background Art

[0002] With the continuous growth of the global population and the continuous improvement of people's living standards, the demand for water resources is increasing. According to the United Nations, each person in the city needs about 1,000 cubic meters of fresh water per year to survive. In the past 20 years, the global

[0003] The demand for drinking water exceeds the supply by 40%. In addition, the rapid development of industrialization in recent years has also brought great challenges to safe water use. Industrial sewage and wastewater increase at a rate of 1.8 billion cubic meters each year. A large amount of industrial sewage and wastewater is directly discharged into the water body, aggravating the pollution of the water environment. Therefore, water shortage and water pollution are important survival crises that humans must face, and my country has never faced such a great threat in terms of water resources.

[0004] In order to realize the recycling of water resources, ensure the safety of drinking water, and kill pathogenic microorganisms in water that are harmful to health, people disinfect drinking water. During the water disinfection process, disinfectants react with organic matter in the water through oxidation, addition, and substitution to generate disinfection by-products (DBPs).

[0005] In 1974, DBPs chloroform was detected in chlorinated disinfected water. In 1976, the National Cancer Institute of the United States announced that chloroform was carcinogenic to experimental animals, linking DBPs to diseases. As research deepened, it was widely confirmed that chloroform was carcinogenic, teratogenic, and mutagenic, posing a serious threat to human health. Therefore, conducting DBPs testing and monitoring in drinking water has become the key to protecting the health of the general public.

[0006] The DBPs present in drinking water are not single DBPs. Compared with conventional chemical analysis devices and single endpoint toxicity analysis devices, fluorescent probes are more suitable for mixed DBPs detection. Based on transcriptomics analysis of the effect of mixed DBPs after chlorination of water source organic matter on the whole genome expression of human colon cancer cell Caco-2, it was found that two enzymes, cytochrome P450 family 1 subfamily A1 (CYP1A1) and cytochrome P450 family 1 subfamily B1 (CYP1B1), were strongly associated with mixed DBPs. Based on this phenomenon, the corresponding fluorescent probes were synthesized.

[0007] Existing technologies usually use fluorescent probes synthesized based on DBPs biomarkers to detect mixed DBPs, and then use a spectrometer to observe changes in the fluorescence signal, including information such as the intensity and color of the fluorescence, while ignoring important information such as the three-dimensional position and three-dimensional morphology of the luminescent substance. Holography was originally defined as a coherent imaging technology that forms a hologram through interference between object light and reference light. Reconstructing the hologram can achieve three-dimensional imaging and acquisition of object information. Since fluorescence is incoherent light and the wavelengths of the fluorescent probe are inconsistent before and after excitation, stable interference fringes cannot be generated, resulting in the inability of the digital holographic optical path of the existing technology to record the three-dimensional information of the object. Summary of the invention

[0008] The purpose of the present invention is to solve the technical problems that three-dimensional information is ignored when fluorescent probes are used for DBPs detection, and that existing coherent digital holography is difficult to use for holographic recording of fluorescent substances. A disinfection by-product detection device in drinking water based on incoherent correlated digital holography is provided, which records the three-dimensional information of the luminous object to achieve three-dimensional detection of disinfection by-products DBPs, thereby facilitating subsequent in-depth research thereon.

[0009] The technical problem proposed by the present invention is solved in this way:

[0010] A detection device for disinfection byproducts in drinking water based on incoherent correlation digital holography comprises a light source, a spectrometer, a filter, a lens, a spatial light modulator and a CCD camera; the water body to be tested, the spectrometer, the filter, the lens and the spatial light modulator are arranged in sequence on the same axis; the light source is located outside the axis, and the line connecting the light source and the spectrometer is perpendicular to the axis; the CCD camera is located outside the axis, and forms an angle with the spatial light modulator;

[0011] A solution prepared by synthesizing fluorescent probes for disinfection by-product biomarkers is pre-added to a water body to be tested and mixed thoroughly; a light source emits a green laser, which is reflected by a spectrometer to reach the water body to be tested, and then refracted into the water body to be tested, exciting the fluorescent probe in the water body to be tested; when the fluorescent probe is exposed to the disinfection by-products and excited by the green laser, yellow fluorescence is generated; the yellow fluorescence passes through the spectrometer and reaches the filter; the filter filters out the green laser and environmental interference light, and then collimates the light through a lens; the collimated light beam reaches a spatial light modulator, and diffraction, splitting and phase shifting are performed on the spatial light modulator by loading a phase mask to obtain a beam of plane light and a beam of spherical light; the interference pattern of the plane light and the spherical light is recorded by a CCD camera to complete the detection of disinfection by-products in drinking water.

[0012] Furthermore, the wavelength of the green laser emitted by the light source is 535 nm, and the wavelength of the yellow fluorescence is 590 nm.

[0013] Furthermore, the beam splitter is a dichroic mirror, and the central wavelength of the filter is 590 nm.

[0014] Furthermore, when the interference light beam is a plane light beam and a spherical light beam, a point source Fresnel hologram is obtained, and the output light signal R(x, y) of the spatial light modulator is expressed as:

[0015]

[0016] Where x and y represent the horizontal and vertical coordinate variables of the output light signal, i is the symbol of the imaginary part, λ represents the central wavelength of the yellow fluorescence, θ is the phase constant, and a is the focal length of the spatial light modulator when it is equivalent to a lens system; the function Q represents the quadratic phase function, Q(b)=exp[iπb(x 2 +y 2 ) / λ] is used to simplify the formula, and b is the independent variable of function Q.

[0017] Furthermore, when the point source is located at (0, 0, z s ), the distance between the point source and the lens is set to fz s , where f is the focal length of the lens, a value of Q[1 / (fz s )]; the transmission function of light propagating behind the lens is Q(-1 / f), and the complex amplitude of the light wave behind the lens is Q[1 / (fz s )] × Q(-1 / f) = Q{z s / [f(fz s )]}.

[0018] Furthermore, when the light propagates a distance d1 from the lens to the optical diffraction element of the spatial light modulator, the complex amplitude of the light wave is Q{z s / [f(fz s )+z s d1]}; According to formula (1), after passing through the spatial light modulator, the complex amplitude of the light wave is related to Q{z s / [f(fz s )+z s d1][1+Q(-1 / a)exp(iθ)]} association;

[0019] Finally, the recorded hologram I is on the CCD camera plane at a distance d2 from the spatial light modulator. p (x, y) is:

[0020]

[0021] Where A is a constant coefficient and || represents modulo.

[0022] Furthermore, from the point source (0, 0, z s) recorded by the hologram, generalized to a point source at any position (x s ,y s , z s ), the recorded hologram is expressed as:

[0023]

[0024] Among them, γ(z s )=[d2-az s (d1a+d2f-af+d2a-d1d2)f -2 ] / [1-z s (a+f-d1)f -2 ].

[0025] Furthermore, for the water body to be tested in the disinfection byproduct detection, its three-dimensional position function is expressed as g(x s ,y s , z s ), then the two-dimensional hologram recorded by the CCD camera is expressed as:

[0026]

[0027] Among them, C is a constant term.

[0028] Furthermore, based on the phase shift technology, three holograms of the same water body to be tested are recorded, and each two-dimensional hologram corresponds to a different phase constant θ, thereby obtaining the final complex-valued hologram H of the water body to be tested. F (x, y) is expressed as:

[0029]

[0030] Among them, H k (x, y) is the kth recorded hologram, and its phase constant is θ k , k=1,2,3.

[0031] Through the Fresnel propagation function, from the complex-valued hologram H F (x, y) to reconstruct a three-dimensional image s(x, y, z s ):

[0032]

[0033] Among them, the symbol * represents the convolution operation;

[0034] The reconstructed result s(x, y, z) obtained in formula (6) s ), from the three-dimensional image s(x, y, z s) can observe the three-dimensional position and three-dimensional morphological information of the excited fluorescent probe in the water body to be tested, thereby realizing the detection of disinfection water by-products based on incoherent digital holography.

[0035] The beneficial effects of the present invention are:

[0036] (1) In the prior art, fluorescent probes are used to study the toxicity of DBPs. Traditional devices ignore the phase information of the light signal, that is, the three-dimensional information of the luminous object. The device described in the present invention can obtain the three-dimensional position, three-dimensional morphology and other information of the luminous object, which is conducive to in-depth research on DBPs.

[0037] (2) The related digital holography in the prior art is not suitable for fluorescent probes to detect incoherent fluorescence generated in DBPs. The device described in the present invention utilizes the spatial self-coherence characteristics of a point light source and realizes light splitting through a spatial light modulator, thereby generating interference fringes and capturing a hologram of the fluorescent object in the camera.

[0038] (3) The device described in the present invention combines fluorescent probe detection and incoherent correlation digital holography technology, uses a camera to obtain a hologram, and then reconstructs it on a computer based on the hologram to achieve three-dimensional detection of disinfectant by-products.

[0039] (4) The device of the present invention is simple to implement and easy to operate, and is also highly practical and suitable for popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of the optical path of the disinfection water byproduct detection device based on incoherent correlation digital holography according to the present invention;

[0041] Figure 2 It is a schematic diagram of the principle of the incoherent correlation digital holography FINCH of the present invention. DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0043] Disinfection water byproducts are carcinogenic, teratogenic and mutagenic, which seriously threaten human health. Therefore, carrying out drinking water DBPs detection and monitoring has become the key to protecting the health of the general public. When using fluorescent probes to detect disinfection water byproducts, after being excited by the excitation light, the fluorescent probes exposed to the disinfection byproduct environment will produce a light signal different from the excitation light, and the light signal can be used to detect DBPs.

[0044] This embodiment provides a detection device for disinfection byproducts in drinking water based on incoherent correlation digital holography, and its optical path diagram is shown in FIG. Figure 1 As shown, the principle diagram is as follows Figure 2As shown, it includes a light source, a spectrometer, a filter, a lens, a spatial light modulator and a CCD camera; the water body to be measured, the spectrometer, the filter, the lens and the spatial light modulator are arranged in sequence on the same axis; the light source is located outside the axis, and the line connecting the light source and the spectrometer is perpendicular to the axis; the CCD camera is located outside the axis, and forms an angle with the spatial light modulator;

[0045] The solution prepared by synthesizing the fluorescent probe for the disinfection byproduct biomarker is added to the water to be tested in advance, and ensures that it is fully mixed;

[0046] The LED light source emits green light, which is reflected by the spectrometer and reaches the water body to be tested, and then refracted into the water body to be tested, exciting the fluorescent probe in the water body to be tested; when the fluorescent probe is exposed to the disinfection by-products and excited by the excitation light, it causes a change in the fluorescence signal to produce yellow fluorescence; the yellow fluorescence passes through the spectrometer and reaches the filter; the filter filters out the green light interference of the green LED light source and the ambient light interference; then it passes through the lens, which is used to collimate the light; the collimated light beam reaches the spatial light modulator, where it is diffracted, split and phase-shifted by loading a phase mask to obtain a beam of plane light and a beam of spherical light, and the interference pattern of the plane light and the spherical light is recorded by a CCD camera.

[0047] In this embodiment, the wavelength of the green LED light source is 535 nm, the wavelength of the yellow fluorescence is 590 nm, the beam splitter is a dichroic mirror, and the central wavelength of the filter is 590 nm.

[0048] When the interference beam is a plane beam and a spherical beam, a point source Fresnel hologram is obtained, and the output light signal R(x, y) of the spatial light modulator is expressed as:

[0049]

[0050] Where x and y represent the horizontal and vertical coordinate variables of the output light signal, i is the symbol of the imaginary part, λ represents the central wavelength of the yellow fluorescence, θ is the phase constant, and a is the focal length of the spatial light modulator when it is equivalent to a lens system; the function Q represents the quadratic phase function, Q(b)=exp[iπb(x 2 +y 2 ) / λ] is used to simplify the formula, b is the independent variable of function Q, and the constant term in formula (1) represents a plane wave, and the quadratic phase term represents a spherical wave. From the function of formula (1), the spatial light modulator can be regarded as the sum of two overlapping imaging systems, namely a plane mirror system and a lens system with a focal length of a.

[0051] When the point source is located at (0, 0, z s ), the focal point of the lens is taken as the origin, and the distance between the point source and the lens is set to fz s, where f is the focal length of the lens, a value of Q[1 / (fz s )] divergent spherical wave. The transmission function of light propagating after the lens is Q(-1 / f), so the complex amplitude of the light wave after the lens is Q[1 / (fz s )] × Q(-1 / f) = Q{z s / [f(fz s )]}.

[0052] When the light propagates a distance d1 from the lens to the optical diffraction element of the spatial light modulator, the complex amplitude of the light wave becomes Q{z s / [f(fz s )+z s d1]}. According to formula (1), after passing through the optical diffraction element of the spatial light modulator, the complex amplitude of the wave is related to Q{z s / [f(fz s )+z s d1][1+Q(-1 / a)exp(iθ)]} is related.

[0053] Finally, the recorded hologram intensity I p (x, y) is:

[0054]

[0055] Among them, A is a constant coefficient, || represents modulus; when z s When is much smaller than f, the first term of formula (2) can be approximately regarded as a constant.

[0056] From the point source (0, 0, z s ) can be extended to any point source (x s ,y s , z s ), the recorded hologram can be expressed as:

[0057]

[0058] Among them, γ(z s )=[d2-az s (d1a+d2f-af+d2ad1d2)f -2 ] / [1-z s (a+f-d1)f -2 ].

[0059] Furthermore, for any three-dimensional object, such as the water body to be tested in disinfection byproduct detection, its three-dimensional position function is expressed as g(x s ,y s , zs ), then the two-dimensional hologram recorded by the CCD camera can be expressed as:

[0060]

[0061] Among them, C is a constant term.

[0062] In order to remove the problems of zero-order terms and conjugate images in the diffraction reconstruction process caused by the coaxial optical path, three holograms of the same object are recorded with the help of phase shifting technology. Each hologram has a different phase constant θ, thus obtaining the final complex-valued hologram H of the three-dimensional object. F (x, y) is expressed as:

[0063]

[0064] Among them, H k is the kth recorded hologram, and the phase constant is θ k .

[0065] Through the Fresnel propagation function, the hologram H F (x, y) to reconstruct a three-dimensional image s(x, y, z s ), specifically expressed as:

[0066]

[0067] Among them, the symbol * represents the convolution operation.

[0068] The reconstructed result s(x, y, z) obtained in formula (6) s ), the three-dimensional position and three-dimensional shape of the object and other related information can be observed, thereby realizing the detection of disinfectant by-products based on incoherent digital holography.

[0069] The disinfection water byproduct detection device based on incoherent correlation digital holography can determine whether the water body to be tested contains disinfection byproducts and provide three-dimensional information of the luminescent object. During the detection process, if the water body mixed with the fluorescent probe does not contain disinfection byproducts, no fluorescence will be generated, and the hologram cannot be obtained using the CCD; on the contrary, if it contains disinfection byproducts, the fluorescent probe is exposed to the disinfection byproduct environment and is excited by the excitation light to produce yellow fluorescence. The hologram can be recorded and reconstructed through the incoherent correlation digital holography method, thereby obtaining the three-dimensional structural information of the luminescent object.

[0070] In summary, the disinfection water byproduct detection device based on incoherent correlation digital holography of the present invention can effectively utilize the generated incoherent fluorescence to obtain a hologram when performing fluorescent probe detection of disinfection water byproducts, thereby realizing three-dimensional detection of objects. The present invention has a wide range of applications and is suitable for vigorous promotion in the technical field or in a technical field close to the technical field.

[0071] The structures listed above are only basic structures of the present invention as examples and should not be used to limit the scope of protection of the present invention. Any changes or modifications that are made to the main design concept and spirit of the present invention and have no substantive significance, and the technical problems they solve are still consistent with the present invention, should be included in the scope of protection of the present invention.

Claims

1. A detection device for disinfection byproducts in drinking water based on incoherent correlation digital holography, characterized in that: It includes a light source, a spectrometer, a filter, a lens, a spatial light modulator and a CCD camera; the water body to be measured, the spectrometer, the filter, the lens and the spatial light modulator are arranged in sequence on the same axis; the light source is located outside the axis, and the line connecting the light source and the spectrometer is perpendicular to the axis; The CCD camera is located off-axis, forming an angle with the spatial light modulator; A solution prepared by synthesizing fluorescent probes for disinfection by-product biomarkers is pre-added to a water body to be tested and mixed thoroughly; a light source emits a green laser, which is reflected by a spectrometer to reach the water body to be tested, and then refracted into the water body to be tested, exciting the fluorescent probe in the water body to be tested; when the fluorescent probe is exposed to the disinfection by-products and excited by the green laser, yellow fluorescence is generated; the yellow fluorescence passes through the spectrometer and reaches the filter; the filter filters out the green laser and environmental interference light, and then collimates the light through a lens; the collimated light beam reaches a spatial light modulator, and diffraction, splitting and phase shifting are performed on the spatial light modulator by loading a phase mask to obtain a beam of plane light and a beam of spherical light; the interference pattern of the plane light and the spherical light is recorded by a CCD camera to complete the detection of disinfection by-products in drinking water.

2. The device for detecting disinfection byproducts in drinking water based on incoherent correlation digital holography according to claim 1, characterized in that: The wavelength of the green laser emitted by the light source is 535nm, and the wavelength of the yellow fluorescence is 590nm.

3. The device for detecting disinfection byproducts in drinking water based on incoherent correlation digital holography according to claim 1, characterized in that: The beam splitter is a dichroic mirror and the center wavelength of the filter is 590nm.

4. The device for detecting disinfection byproducts in drinking water based on incoherent correlation digital holography according to claim 1, characterized in that: When the interference beam is a plane beam and a spherical beam, a Fresnel hologram of an arbitrary point source is obtained, and the output optical signal R(x, y) of the spatial light modulator is expressed as: Where x and y represent the horizontal and vertical coordinate variables of the output light signal, i is the symbol of the imaginary part, λ represents the central wavelength of the yellow fluorescence, θ is the phase constant, and a is the focal length of the spatial light modulator when it is equivalent to a lens system; the function Q represents the quadratic phase function, Q(b)=exp[iπb(x 2 +y 2 ) / λ] is used to simplify the formula, and b is the independent variable of function Q.

5. The device for detecting disinfection byproducts in drinking water based on incoherent correlation digital holography according to claim 4, characterized in that: When the point source is located at (0, 0, z s ), the distance between the point source and the lens is set to fz s , where f is the focal length of the lens, a value of Q[1 / (fz s )]; the transmission function of light propagating behind the lens is Q(-1 / f), and the complex amplitude of the light wave behind the lens is Q[1 / (fz s )] × Q(-1 / f) = Q{z s / [f(fz s )]}.

6. The device for detecting disinfection byproducts in drinking water based on incoherent correlation digital holography according to claim 5, characterized in that: When the light propagates a distance d1 from the lens to the optical diffraction element of the spatial light modulator, the complex amplitude of the light wave is Q{z s / [f(fz s )+z s d1]}; According to formula (1), after passing through the spatial light modulator, the complex amplitude of the light wave is related to Q{z s / [f(fz s )+z s d1][1+Q(-1 / a)exp(iθ)]} association; Finally, the recorded hologram I is on the CCD camera plane at a distance d2 from the spatial light modulator. p (x, y) is: Where A is a constant coefficient and || represents modulo.

7. The device for detecting disinfection byproducts in drinking water based on incoherent correlation digital holography according to claim 6, characterized in that: From the point source (0, 0, z s ) recorded by the hologram, generalized to a point source at any position (x s ,y s , z s ), the recorded hologram is expressed as: where γ(z s ) = [d2 - a - z s (d1a + d2f - af + d2a - d1d2)f -2 / [1 - z s (a + f - d1)f -2 .

8. The device for detecting disinfection byproducts in drinking water based on incoherent correlation digital holography according to claim 7, characterized in that: For the water body to be tested in the disinfection byproduct detection, its three-dimensional position function is expressed as g(x s ,y s , z s ), then the two-dimensional hologram recorded by the CCD camera is expressed as: Among them, C is a constant term.

9. The device for detecting disinfection byproducts in drinking water based on incoherent correlation digital holography according to claim 8, characterized in that: Based on the phase shift technology, three holograms of the same water body to be tested are recorded. Each two-dimensional hologram corresponds to a different phase constant θ, thereby obtaining the final complex-valued hologram H of the water body to be tested. F (x, y) is expressed as: Among them, H k (x, y) is the kth recorded hologram, and its phase constant is θ k , k=1,2,3. Through the Fresnel propagation function, from the complex-valued hologram H F (x, y) to reconstruct a three-dimensional image s(x, y, z s ): Among them, the symbol * represents the convolution operation; The reconstructed result s(x, y, z) obtained in formula (6) s ), from the three-dimensional image s(x, y, z s ) can observe the three-dimensional position and three-dimensional morphological information of the excited fluorescent probe in the water body to be tested, thereby realizing the detection of disinfection water by-products based on incoherent digital holography.

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