Optical fiber liquid fluorescence concentration measuring device

Abstract

The utility model provides an optical fiber liquid fluorescence concentration measuring device. The optical fiber liquid fluorescence concentration measuring device comprises a cassette, an amplifying circuit, a pull-out switch, an exciting light path, a clustered optical fiber probe, a collecting light path and a cuvette, the excitation light path comprises a semiconductor laser, a narrow-band filter and an excitation optical fiber, and the collection light path comprises a collection optical fiber, a lens support group, two lenses, a dichroscope, a light trap and a silicon photodiode. According to the utility model, the forked optical fiber structure is adopted to form a non-confocal optical path structure, and the photomultiplier replaces a charge-coupled device to serve as a detector, so that compared with the prior art, various inconveniences brought by a large-scale optical instrument in the use process are avoided. In the device provided by the utility model, the optical fiber with the forked structure is adopted, and the excitation end and the collection end are separated, so that the problem of steric hindrance is solved, and the influence of excitation light on collected signals is reduced. The device is small in size, easy to move, low in cost and more suitable for actual use.

Description

Technical Field

[0001] This utility model relates to the field of fluorescence concentration detection technology, and in particular to an optical fiber liquid fluorescence concentration measuring device. Background Technology

[0002] Liquid fluorescence concentration measurement devices can convert the information of a target analyte into a fluorescence signal, allowing direct observation of the analyte's presence and distribution for visualized research. These devices also possess high sensitivity, enabling the detection of extremely small amounts of the target analyte. In terms of application needs, many fields have an urgent need for accurate measurement of liquid fluorescence concentration, such as medicine, environmental monitoring, and chemical analysis.

[0003] Currently, the main detection receivers for liquid fluorescence concentration measurement devices include spectrophotometers, microscopes, and CCD cameras. However, these receivers suffer from drawbacks such as high device cost, demanding operational requirements, and susceptibility to external interference. While photoelectric technology can convert acquired fluorescence signals into digital output signals, the resulting devices suffer from problems such as high noise, low detection limits, and low fluorescence signal intensity.

[0004] In 2017, Kahramangil et al.'s research team explored a technology combining fiber optic probes with fluorescence imaging, using fiber optic probes for front-end sampling and detection. This method could solve the problem of large-area sample obstruction, but it still failed to solve the problem of ambient light interference. Furthermore, the device suffered from poor integration and operability. In 2020, Nanjing Raylanse Co., Ltd. researched a technology combining a spectrometer and an optical detection probe, but it failed to solve the problems of complex device design, low operability, and high cost, hindering widespread application. Utility Model Content

[0005] To address the aforementioned technical problems, this invention provides an optical fiber liquid fluorescence concentration measurement device. This invention primarily employs short, straight, parallel optical fibers, solving the problems of significant signal attenuation and susceptibility to external vibration interference caused by long, flexible optical fibers. A pull-out switch is added between the semiconductor laser and the collecting optical fiber, resolving the issue of unstable laser power due to frequent switching of the semiconductor laser. To address the high noise problem associated with stray light collection using short optical fibers, a dichroic mirror and an optical trap are added, reflecting stray light through the dichroic mirror to the optical trap for absorption. The technical means employed in this invention are as follows:

[0006] A fiber optic liquid fluorescence concentration measurement device includes: a dark box and an amplification circuit, a pull-out switch, an excitation optical path, a bundled fiber optic probe, a collection optical path, and a cuvette disposed inside the dark box;

[0007] The excitation optical path includes a semiconductor laser, a narrowband filter, and an excitation fiber. The semiconductor laser is installed at the bottom of the dark box. The pull-out switch is located between the semiconductor laser and the narrowband filter. The narrowband filter is located between the pull-out switch and the excitation fiber. One end of the excitation fiber is connected to the narrowband filter.

[0008] The optical path includes a collecting fiber, a lens support assembly, two lenses, a dichroic mirror, an optical trap, and a silicon photodiode. The lens support assembly is installed at the bottom of the dark box. The two lenses and the dichroic mirror are both located inside the lens support assembly. The optical trap and the silicon photodiode are installed on two adjacent sidewalls of the lens support assembly. One end of the collecting fiber is connected to one of the lenses. The dichroic mirror is located between the two lenses. The lens on the other side is connected to the silicon photodiode. An amplification circuit located outside the lens support assembly is connected to the silicon photodiode.

[0009] The other ends of the excitation fiber and the collection fiber are connected to one side of the bundled fiber optic probe. The excitation fiber, the bundled fiber optic probe and the collection fiber form an integral branched structure with the front end placed in parallel and the rear end branched. The other side of the bundled fiber optic probe is in close contact with the surface of the cuvette, and the two together constitute the detection optical path.

[0010] Furthermore, the pull-out switch includes a drawstring baffle and two slide rails, the two slide rails being vertically parallel and installed at the bottom of the junction box, and the drawstring baffle being vertically slidably connected to the two slide rails.

[0011] Furthermore, the propagation path of light in the excitation optical path and the propagation path of the collected signal in the collection optical path are located in the same plane.

[0012] Furthermore, the two lenses and the dichroic mirror are coaxially arranged, the dichroic mirror is placed at an angle of 45° to 60° with the optical axis of the lens, and the light trap is located in the direction perpendicular to the optical axis of the lens and in the reflected light path of the dichroic mirror.

[0013] Furthermore, the excitation center wavelength of the semiconductor laser is 750nm to 770nm; the center wavelength of the narrowband filter is 740nm to 820nm, and the bandwidth is 10nm to 20nm; the dichroic mirror has high reflectivity for light with wavelengths less than 770nm, with a reflectivity greater than or equal to 95%; the dichroic mirror has high transmittance for light with wavelengths greater than 810nm, with a transmittance greater than or equal to 95%; and the optical trap has an absorption rate of greater than or equal to 90% for stray light entering it.

[0014] Furthermore, the excitation optical path also includes a narrowband filter holder installed at the bottom of the dark box, the narrowband filter being placed on the narrowband filter holder, and the cross-section of the narrowband filter being parallel to that of the excitation optical fiber.

[0015] Furthermore, the bundled fiber optic probe consists of nine collecting fibers with a length of 170mm to 180mm and a diameter of 0.5mm to 0.6mm surrounding a single excitation fiber with a length of 150mm to 160mm and a diameter of 0.8mm to 0.9mm.

[0016] Furthermore, the fiber material of the bundled fiber optic probe is quartz multimode fiber with a numerical aperture of 0.24–0.37 mm.

[0017] Furthermore, the silicon photodiode is connected to a data acquisition card.

[0018] Furthermore, when using CY7 fluorescent dye for testing, the detection range is 1×10⁻⁶. -12 mol / L~1×10 -8 mol / L CY7 fluorescent dye was placed in a cuvette.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. The fiber optic liquid fluorescence concentration measuring device provided by this utility model adopts a short, straight bundled fiber optic probe, which directly separates the excitation fiber and the collection fiber at one end, shortening the fiber length. The total length of the fiber used in the measuring device is within 180mm, which solves the problems of significant attenuation of optical signal and susceptibility to external vibration interference caused by excessively long optical fibers.

[0021] 2. The fiber optic liquid fluorescence concentration measuring device provided by this utility model, through the pull-out switch design, effectively avoids the instability of laser power caused by the continuous starting and stopping of the laser, improves the stability of the experimental excitation source, and enhances the accuracy of the measurement results.

[0022] 3. The fiber optic liquid fluorescence concentration measuring device provided by this utility model solves the problem of high noise when collecting stray light by adding a dichroic mirror and an optical trap, which reflects stray light through the dichroic mirror to the optical trap for absorption.

[0023] Based on the above reasons, this utility model can be widely promoted in fields such as fluorescence concentration detection. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1This is a schematic diagram of the overall structure of the fiber optic liquid fluorescence concentration measuring device of this utility model.

[0026] Figure 2 This is a partial structural schematic diagram of an optical fiber liquid fluorescence concentration measuring device according to the present invention.

[0027] Figure 3 This is a linear curve of the concentration of the CY7 fluorescent dye detected by this invention, with a concentration range of 2.5 × 10⁻⁶. - 12 mol / L~1×10 -8 mol / L.

[0028] In the diagram: 1. Dark box; 2. Amplifier circuit; 3. Semiconductor laser; 4. Drawstring baffle; 5. Slide rail; 6. Narrowband filter holder; 7. Narrowband filter; 8. Excitation fiber; 9. Bundled fiber optic probe; 10. Collection fiber; 11. Lens holder assembly; 12. Lens; 13. Dichroic mirror; 14. Optical trap; 15. Silicon photodiode; 16. Cuvette; 17. Data acquisition card. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0030] Example 1

[0031] This utility model provides a fiber optic liquid fluorescence concentration measuring device, which is a multimode fiber optic liquid fluorescence concentration measuring device, including: a dark box 1, an amplifier circuit 2, a semiconductor laser 3, a drawstring baffle 4, two slide rails 5, a narrowband filter support 6, a narrowband filter 7, an excitation fiber 8, a bundled fiber optic probe 9, a collecting fiber optic 10, a lens support group 11, a lens 12, a dichroic mirror 13, an optical trap 14, a silicon photodiode 15, a cuvette 16, and a data acquisition card 17.

[0032] The drawstring baffle 4 and the two slide rails 5 form a pull-out switch. The two slide rails 5 are vertically parallel and installed at the bottom of the junction box 1. The drawstring baffle 4 is vertically slidably connected to the two slide rails 5 and can slide up and down on the slide rails 5.

[0033] The excitation optical path consists of a semiconductor laser 3, a drawstring baffle 4, a slide rail 5, a narrowband filter holder 6, a narrowband filter 7, and an excitation fiber 8. The semiconductor laser 3 is installed at the bottom of the dark box 1. A pull-out switch is located between the semiconductor laser 3 and the narrowband filter 7. The narrowband filter 7 is located between the pull-out switch (formed by the drawstring baffle 4 and the slide rail 5) and the excitation fiber 8. One end of the excitation fiber 8 ( Figure 1 The right end of the middle section is connected to the narrowband filter 7. The narrowband filter support 6 is installed at the bottom of the dark box 1. The narrowband filter 7 is placed on the narrowband filter support 6. The narrowband filter 7 is placed parallel to the cross section of the excitation fiber 8.

[0034] The optical collecting path consists of an optical fiber 10, a lens support assembly 11, two lenses 12, a dichroic mirror 13, an optical trap 14, and a silicon photodiode 15. The lens support assembly 11 is installed at the bottom of the dark box 1. The two lenses 12 and the dichroic mirror 13 are both located inside the lens support assembly 11. The optical trap 14 and the silicon photodiode 15 are installed on two adjacent sidewalls of the lens support assembly 11. Figure 1 In the middle, the optical trap 14 is mounted on the front side wall of the lens support assembly 11, and the silicon photodiode 15 is mounted on the right side wall of the lens support assembly 11, collecting one end of the optical fiber 10 ( Figure 1 (middle right end) and one side ( Figure 1 The lenses 12 on the left side are connected, and the dichroic mirror 13 is placed between the two lenses 12. On the other side ( Figure 1 The lens 12 (on the right side) is connected to the silicon photodiode 15. The amplifier circuit 2 located outside the lens support assembly 11 is connected to the silicon photodiode 15. The silicon photodiode 15 is connected to the data acquisition card 17 (using an existing data acquisition card). The two lenses 12 and the dichroic mirror 13 are coaxially arranged. The light trap 14 is located in the direction perpendicular to the optical axis of the lens 12 and is located in the reflected light path of the dichroic mirror 13.

[0035] The excitation fiber 8 and the collection fiber 10 are connected in parallel, and the other ends of the excitation fiber 8 and the collection fiber 10 ( Figure 1 The middle left end) is connected to one side of the bundled fiber optic probe 9 ( Figure 1 The right side of the middle section is connected to the excitation fiber 8, the bundled fiber probe 9, and the collection fiber 10, which together form an integrated bifurcated structure with the front end placed parallel and the rear end bifurcated; the other side of the bundled fiber probe 9 ( Figure 1 (The middle left side) is closely attached to the surface of cuvette 16, and the two together constitute the detection optical path.

[0036] The laser emitted by the semiconductor laser 3 passes through the open pull-out switch, through the narrowband filter 7, into the excitation fiber 8, and the clustered fiber optic probe 9 to reach the cuvette 16. The laser induces a fluorescence signal, which then passes through the clustered fiber optic probe 9, the collecting fiber 10, the lens 12, the dichroic mirror 13, the narrowband filter 7, and the lens 12 to reach the silicon photodiode 15.

[0037] This invention employs a branched fiber optic structure to form a non-confocal optical path, using a photomultiplier tube (PMT) instead of a charge-coupled device (CCD) as the detector. Compared with existing technologies, this invention avoids various inconveniences associated with the use of large optical instruments. In this device, the branched fiber structure separates the excitation and collection ends, solving the spatial steric hindrance problem and reducing the influence of excitation light on the collected signal. This invention's device is small, easily portable, and low-cost, making it more suitable for practical applications.

[0038] In a preferred embodiment, the dichroic mirror 13 is coaxially disposed between the two lenses 12, and the dichroic mirror 13 is placed at an angle of 45° to 60° with the optical axis of the lens 12.

[0039] In a preferred embodiment, the excitation center wavelength of the semiconductor laser 3 is 750nm to 770nm; the center wavelength of the narrowband filter 7 is 740nm to 820nm, and the bandwidth is 10nm to 20nm; the dichroic mirror 13 has high reflectivity for light with wavelengths less than 770nm, with a reflectivity greater than or equal to 95%, and high transmittance for light with wavelengths greater than 810nm, with a transmittance greater than or equal to 95%; the optical trap 14 has an absorption rate of greater than or equal to 90% for stray light entering it.

[0040] In a preferred embodiment, the excitation light path and the collection light path are both placed inside the dark box 1, and the propagation path of the light in the excitation light path and the propagation path of the collected signal in the collection light path are both located in the same plane.

[0041] In a preferred embodiment, the bundled fiber optic probe 9 consists of nine collecting fibers 10 with a length of 170mm to 180mm and a diameter of 0.5mm to 0.6mm surrounding an excitation fiber 8 with a length of 150mm to 160mm and a diameter of 0.8mm to 0.9mm.

[0042] As a preferred embodiment, the fiber material of the bundled fiber optic probe 9 is quartz multimode fiber with a numerical aperture of 0.24 to 0.37 mm.

[0043] As a preferred embodiment, when using CY7 fluorescent dye for testing, the detection range is 1×10⁻⁶. -12 mol / L~1×10 -8mol / L CY7 fluorescent dye was placed in cuvette 16.

[0044] Example 2

[0045] A fiber optic liquid fluorescence concentration measurement device includes an excitation light source (semiconductor laser 3) with a center wavelength of 760 nm; a narrowband filter 7 with center wavelengths of 760 nm and 800 nm; a quartz fiber with a diameter of 0.8 mm, a length of 170 mm, and a numerical aperture of 0.37, surrounded by nine quartz fibers with a diameter of 0.6 mm, a length of 170 mm, and a numerical aperture of 0.37, forming a 170 mm long branched bundled fiber optic probe 9; a lens 12 with a focal length of 10 mm as a collimating lens; a dichroic mirror 13 with a reflectivity greater than 95% for light wavelengths greater than 810 nm; and an optical trap 14 capable of absorbing more than 90% of Rayleigh scattered light.

[0046] The liquid fluorescence concentration detection device was used to detect CY7 fluorescent dye, and the detection cell was cuvette 16.

[0047] Experimental results:

[0048] Table 1 Laboratory measurement data of the CY7 fluorescence concentration measuring device

[0049]

[0050] Figure 3 To detect the spectrum, the concentration range of CY7 fluorescent dye was 2.5 × 10⁻⁶. -11 mol / L~1×10 -8 mol / L, its measurement accuracy can reach 1×10 -12 mol / L, meeting the requirements for high-precision measurement.

[0051] Example 3

[0052] Utilize Figure 1 The concentration measuring device shown measures a CY7 fluorescent dye solution of unknown concentration.

[0053] Measurement results:

[0054]

[0055] Substituting the measurement results into the fitted straight line, the concentration of the unknown concentration solution is obtained as: 7.505 × 10⁻⁶. -10 mol / L.

[0056] The concentration of the unknown solution was determined using a spectrometer to be 7.5 × 10⁻⁶. -10 mol / L.

[0057] The results from both methods are very similar, indicating that the concentration measuring device of this invention is highly reliable.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A fiber optic liquid fluorescence concentration measuring device, characterized in that, include: The dark box (1) and the amplifier circuit (2), pull-out switch, excitation optical path, bundled fiber optic probe (9), collection optical path and cuvette (16) are set inside the dark box (1); The excitation optical path includes a semiconductor laser (3), a narrowband filter (7), and an excitation fiber (8). The semiconductor laser (3) is installed at the bottom of the dark box (1). The pull-out switch is located between the semiconductor laser (3) and the narrowband filter (7). The narrowband filter (7) is located between the pull-out switch and the excitation fiber (8). One end of the excitation fiber (8) is connected to the narrowband filter (7). The optical path includes a collecting fiber (10), a lens support group (11), two lenses (12), a dichroic mirror (13), an optical trap (14), and a silicon photodiode (15). The lens support group (11) is installed at the bottom of the dark box (1). The two lenses (12) and the dichroic mirror (13) are both located inside the lens support group (11). The optical trap (14) and the silicon photodiode (15) are installed on two adjacent sidewalls of the lens support group (11). One end of the collecting fiber (10) is connected to one side of the lens (12). The dichroic mirror (13) is located between the two lenses (12). The other side of the lens (12) is connected to the silicon photodiode (15). The amplification circuit (2) located outside the lens support group (11) is connected to the silicon photodiode (15). The other ends of the excitation fiber (8) and the collection fiber (10) are connected to one side of the bundled fiber probe (9). The excitation fiber (8), the bundled fiber probe (9) and the collection fiber (10) form an overall bifurcated structure with the front end placed in parallel and the rear end bifurcated. The other side of the bundled fiber probe (9) is in close contact with the surface of the cuvette (16), and the two together constitute the detection optical path.

2. The fiber optic liquid fluorescence concentration measuring device according to claim 1, characterized in that, The pull-out switch includes a drawstring baffle (4) and two slide rails (5). The two slide rails (5) are vertically parallel and installed at the bottom of the box (1). The drawstring baffle (4) is vertically slidably connected to the two slide rails (5).

3. The fiber optic liquid fluorescence concentration measuring device according to claim 1, characterized in that, The propagation path of light in the excitation optical path and the propagation path of the collected signal in the collection optical path are located in the same plane.

4. The fiber optic liquid fluorescence concentration measuring device according to claim 1, characterized in that, The two lenses (12) and the dichroic mirror (13) are arranged coaxially. The dichroic mirror (13) is placed at an angle of 45° to 60° with the optical axis of the lens (12). The light trap (14) is located in the direction perpendicular to the optical axis of the lens (12) and is located in the reflected light path of the dichroic mirror (13).

5. The fiber optic liquid fluorescence concentration measuring device according to claim 1, characterized in that, The excitation center wavelength of the semiconductor laser (3) is 750nm to 770nm; the center wavelength of the narrowband filter (7) is 740nm to 820nm, and the bandwidth is 10nm to 20nm; the dichroic mirror (13) has high reflectivity for light with wavelengths less than 770nm, with a reflectivity greater than or equal to 95%; the dichroic mirror (13) has high transmittance for light with wavelengths greater than 810nm, with a transmittance greater than or equal to 95%; and the optical trap (14) has an absorption rate of greater than or equal to 90% for stray light entering it.

6. The fiber optic liquid fluorescence concentration measuring device according to claim 1, characterized in that, The excitation optical path also includes a narrowband filter holder (6) installed at the bottom of the dark box (1), the narrowband filter (7) is placed on the narrowband filter holder (6), and the cross-section of the narrowband filter (7) is parallel to that of the excitation optical fiber (8).

7. The fiber optic liquid fluorescence concentration measuring device according to claim 1, characterized in that, The bundled fiber optic probe (9) consists of nine collecting fibers (10) with a length of 170mm to 180mm and a diameter of 0.5mm to 0.6mm surrounding an excitation fiber (8) with a length of 150mm to 160mm and a diameter of 0.8mm to 0.9mm.

8. The fiber optic liquid fluorescence concentration measuring device according to claim 1, characterized in that, The fiber material of the bundled fiber optic probe (9) is quartz multimode fiber with a numerical aperture of 0.24 to 0.37 mm.

9. The fiber optic liquid fluorescence concentration measuring device according to claim 1, characterized in that, The silicon photodiode (15) is connected to a data acquisition card (17).

10. The fiber optic liquid fluorescence concentration measuring device according to claim 1, characterized in that, When using CY7 fluorescent dye for testing, the detection range is 1×10⁻⁶. -12 mol / L~1×10 -8 mol / L, CY7 fluorescent dye was placed in cuvette (16).

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