In-situ ultraviolet and visible spectrophotometer with high measurement precision

Abstract

The invention discloses an in-situ ultraviolet and visible spectrophotometer with high measurement precision, and relates to the technical field of ultraviolet and visible spectrophotometers, the in-situ ultraviolet and visible spectrophotometer comprises a bottom shell, an optical unit is arranged on the inner wall of the bottom of the bottom shell, and a light source module and a monochromator are arranged in the optical unit; the top of the optical unit is fixedly connected with an operation platform through a supporting rod, the top of the operation platform is provided with a motor mounting frame, the top of the motor mounting frame is provided with a linear motor, the output end of the linear motor is connected with a lifting fixing plate, and the lifting fixing plate is of a Z-shaped structure. The end, away from the linear motor, of the lifting fixing plate is connected with a light shield, and the top of the light shield is provided with an optical fiber clamping frame. According to the method, result deviation caused by dilution multiple estimation errors in a traditional method is avoided, the dilution frequency of the high-concentration sample is reduced, reagent consumption and waste liquid generation are reduced, and the method conforms to the green analytical chemistry concept.

Description

Technical Field

[0001] This invention relates to the field of ultraviolet-visible spectrophotometer technology, and in particular to an in-situ ultraviolet-visible spectrophotometer with high measurement accuracy. Background Technology

[0002] The ultraviolet-visible spectrophotometer is an analytical instrument that uses the principle of ultraviolet-visible spectrophotometry to analyze the radiation absorption of molecules in the ultraviolet-visible spectral region.

[0003] In existing technologies, ultraviolet-visible spectrophotometers mainly consist of components such as a light source, monochromator, absorption cell, detector, and signal processor. The function of the light source is to provide a sufficiently intense, stable, and continuous spectrum. Hydrogen lamps or deuterium lamps are typically used in the ultraviolet region, while tungsten lamps or halogen tungsten lamps are typically used in the visible region. The function of the monochromator is to decompose the composite light emitted by the light source and separate the monochromatic light of the desired wavelength. Dispersive elements include prisms and gratings. Glass absorption cells are used for measurements in the visible region, while quartz absorption cells are required for measurements in the ultraviolet region. The function of the detector is to detect the intensity of transmitted light through a photoelectric conversion element, converting the optical signal into an electrical signal.

[0004] However, the above-mentioned UV-Vis spectrophotometer requires multiple dilutions of high-concentration samples before detection, which is quite troublesome. At the same time, the dilution process will cause reagent consumption and waste liquid generation, resulting in sample waste. In addition, the measurement process is prone to deviations due to errors in the estimation of the dilution factor, which will affect the accuracy of the measurement results. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing an in-situ ultraviolet-visible spectrophotometer with high measurement accuracy. Its advantages include avoiding result deviations caused by dilution factor estimation errors in traditional methods, reducing the number of dilutions for high-concentration samples, lowering reagent consumption and waste generation, and aligning with the principles of green analytical chemistry.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A high-precision in-situ ultraviolet-visible spectrophotometer includes a base shell. An optical unit is disposed on the inner bottom wall of the base shell. A light source module and a monochromator are disposed inside the optical unit. An operating platform is fixedly connected to the top of the optical unit via a support rod. A motor mounting bracket is disposed on the top of the operating platform. A linear motor is disposed on the top of the motor mounting bracket. A lifting and fixing plate is connected to the output end of the linear motor. The lifting and fixing plate has a Z-shaped structure. A light shield is connected to the end of the lifting and fixing plate away from the linear motor. A fiber optic clamp is disposed on the top of the light shield. The back of the optical unit is provided with a detection optical fiber, one end of the detection optical fiber away from the optical unit is connected with an optical fiber clamping frame, the top outer wall of the operation platform is provided with a moving stage, the inside of the moving stage is placed with a bottom light transmission cuvette, the bottom light transmission cuvette is made of transparent material, the bottom light transmission cuvette is located directly below the light shield, the bottom of the operation platform is provided with a mirror frame assembly, the inner wall of the fixed box is provided with a lens seat, an optical lens is mounted in the lens seat, the inside of the mirror frame assembly is provided with a main signal plate, the surface of the main signal plate is provided with an optical sensor and a microprocessor.

[0007] Through the above technical scheme: when using, the high-concentration sample to be detected is poured into the bottom light transmission cuvette, the bottom light transmission cuvette is placed in the moving stage, the linear motor is controlled to work to drive the lifting fixed plate to move up and down, the lifting fixed plate moves up and down to drive the light shield to move up and down, the light shield drives the sample to move, so that the optical path can be changed, the optical path of the high-concentration sample is automatically reduced, the optical path of the low-concentration sample is automatically increased, the optical path is continuously adjusted, the absorbance range is always kept in the best measurement interval, the change of the optical path follows the linear relationship of the Lambert-Beer law, the optical path difference can be automatically corrected, the same standard curve is suitable for sample measurement under different optical paths, the result deviation caused by the dilution multiple estimation error in the traditional method is avoided, the dilution times of the high-concentration sample are reduced, the reagent consumption and waste liquid generation are reduced, and the green analysis chemistry concept is met.

[0008] The top of the operation platform is provided with a fiber guide rod, the top of the fiber guide rod is provided with a fiber guide ring, the detection optical fiber passes through the fiber guide ring to form an arc structure, and the static bending radius of the detection optical fiber is 10-15 times of the outer diameter.

[0009] Through the above technical scheme: the setting of the fiber guide rod can bend the detection optical fiber to a certain arc to avoid interference on the optical fiber transmission.

[0010] The top of the operation platform is provided with a fiber guide rod, the top of the fiber guide rod is provided with a fiber guide ring, the detection optical fiber passes through the fiber guide ring to form an arc structure, and the static bending radius of the detection optical fiber is 10-15 times of the outer diameter.

[0011] Through the above technical scheme: the setting of the fiber guide rod can bend the detection optical fiber to a certain arc to avoid interference on the optical fiber transmission.

[0012] The present invention is further configured such that a cuvette slot is provided at the bottom of the operating platform, a reference optical fiber is provided on one side of the cuvette slot, and the end of the reference optical fiber away from the cuvette slot is connected to an optical unit; a reference signal board assembly is provided on the other side of the cuvette slot, and the reference signal board assembly includes a lens barrel and a lens.

[0013] Through the above technical solutions, a stable calibration solution can be added to the cuvette during testing, allowing for point-by-point correction within the weighted range, generating a compensation equation, and ensuring highly accurate optical path control.

[0014] The present invention is further configured such that a reference light shield is provided on the top of the cuvette tank, and the reference light shield is connected to the cuvette tank by magnetic attraction.

[0015] The above technical solution involves setting up a reference light shield to block light from the sample in the cuvette, thus preventing external light from interfering with the detection.

[0016] The present invention is further configured such that a guide rod is provided on the top of the motor mounting bracket, and a guide hole is provided on the top of the lifting fixing plate, the guide rod passes through the guide hole, and the lifting fixing plate slides along the outer wall of the guide rod.

[0017] The above technical solution, with the guide rod, allows the lifting and fixing plate to slide up and down along the guide rod, improving the stability of the sunshade's movement.

[0018] The present invention is further configured such that the operation of the linear motor can change the optical path, the change of the optical path follows the Lambert-Beer law, and the formula for the change of the optical path is: A=ε*c*l, where A is absorbance, ε is molar absorptivity, c is concentration, and l is optical path. The above technical solutions enable precise measurement of samples of different concentrations by changing the optical path.

[0019] The present invention is further configured such that the moving interval distance of the linear motor is 0.005 mm.

[0020] The above technical solutions enable minute changes in the optical path, effectively avoiding the problem of focal point changes caused by moving the optical fiber or sensor position, ensuring that the light spot obtained by the receiver remains constant, and achieving better measurement accuracy.

[0021] A method for using a high-precision in-situ ultraviolet-visible spectrophotometer includes the following steps: Step 1: Pour the high-concentration sample to be tested into the bottom-transmitting cuvette and place the bottom-transmitting cuvette in the moving stage; Step 2: Controlling the linear motor will cause the lifting and fixing plate to move up and down. The movement of the lifting and fixing plate will cause the light shield to move up and down, and the light shield will move the sample. This will change the optical path. The optical path will be automatically reduced for high-concentration samples and automatically increased for low-concentration samples. By continuously adjusting the optical path, the absorbance range will always be kept in the optimal measurement range. Step 3: The optical path change follows the linear relationship of Lambert-Beer's law, which can automatically correct for optical path differences. The same standard curve is applicable to sample measurements under different optical paths. Multiple optical paths can be automatically switched in a short time to measure the corresponding absorbance. With the optical path as the horizontal axis and the absorbance as the vertical axis, the slope of the fitted straight line can be obtained. According to Lambert-Beer's law, the concentration can be directly calculated without the need for a standard curve. The result can be obtained in one measurement.

[0022] The beneficial effects of this invention are as follows: 1. Wide dynamic range. Reduces sample pretreatment; automatically reduces optical path for high-concentration samples and automatically increases optical path for high-concentration samples, always keeping the absorbance range within the optimal measurement range.

[0023] 2. Improve analytical accuracy and flexibility. Precisely match the linear range; by continuously adjusting the optical path, the absorbance is always kept within the instrument's optimal linear range, avoiding result deviations caused by dilution factor estimation errors in traditional methods.

[0024] 3. No need to redraw the standard curve. The optical path change follows a linear relationship with the Lambert-Beer law, and the difference in optical path can be automatically corrected by software. The same standard curve is applicable to sample measurements under different optical paths.

[0025] 4. Saves reagent and sample volume. Sample volumes can be as low as microliters (e.g., 10µL), making it suitable for precious samples (e.g., biological tissue extracts, cell lysates) or scenarios where reagent costs are high (e.g., enzyme-linked immunosorbent assay, ELISA).

[0026] 5. Environmental protection and economy. Reducing the number of dilutions for high-concentration samples lowers reagent consumption and waste generation, aligning with the principles of green analytical chemistry. Attached Figure Description

[0027] Figure 1 This is a three-dimensional structural diagram of an in-situ ultraviolet-visible spectrophotometer with high measurement accuracy proposed in this invention; Figure 2 This is a partially enlarged structural diagram of an in-situ ultraviolet-visible spectrophotometer with high measurement accuracy proposed in this invention. Figure 3 This is a side view of the structure of an in-situ ultraviolet-visible spectrophotometer with high measurement accuracy proposed in this invention. Figure 4This is a rear-view structural diagram of an in-situ ultraviolet-visible spectrophotometer with high measurement accuracy proposed in this invention.

[0028] In the diagram: 1. Bottom shell; 2. Optical unit; 3. Optical coupler board; 4. Optical coupler mounting bracket; 5. Linear motor; 6. Reference fiber; 7. Operating platform; 8. Motor mounting bracket; 9. Support rod; 10. Reference light shield; 11. Cuvette slot; 12. Reference signal board assembly; 13. Lens frame assembly; 14. Main signal board; 15. Bottom transparent cuvette; 16. Moving stage; 17. Light shield; 18. Fiber optic clamp; 19. Guide rod; 20. Lifting and fixing plate; 21. Detection fiber; 22. Fiber optic guide rod; 23. Optical coupler shield. Detailed Implementation

[0029] The technical solution of this patent will be further described in detail below with reference to specific embodiments.

[0030] The embodiments of this patent are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this patent, and should not be construed as limiting this patent.

[0031] Reference Figures 1-4 A high-precision in-situ ultraviolet-visible spectrophotometer includes a base shell 1. An optical unit 2 is provided on the bottom inner wall of the base shell 1. A light source module and a monochromator are provided inside the optical unit 2. An operating platform 7 is fixedly connected to the top of the optical unit 2 by a support rod 9. A motor mounting bracket 8 is provided on the top of the operating platform 7. A linear motor 5 is provided on the top of the motor mounting bracket 8. A lifting fixing plate 20 is connected to the output end of the linear motor 5. The lifting fixing plate 20 has a Z-shaped structure. A light shield 17 is connected to the end of the lifting fixing plate 20 away from the linear motor 5. A fiber optic clamp 18 is provided on the top of the light shield 17. A detection fiber 21 is provided on the back of the optical unit 2. The end of the detection fiber 21 away from the optical unit 2 is connected to the fiber optic clamp 18. A movable stage 16 is provided on the top outer wall of the operating platform 7. A bottom-transparent cuvette 15 is placed inside the movable stage 16. The bottom-transparent cuvette 15 is made of transparent material and is located directly below the light shield 17. A lens frame assembly 13 is provided at the bottom of the operating platform 7. The lens frame assembly 13 includes a fixing box. A lens mount is provided on the inner wall of the fixing box. An optical lens is installed inside the lens mount. A main signal board 14 is provided inside the lens frame assembly 13. An optical sensor and a microprocessor are provided on the surface of the main signal board 14.

[0032] In this embodiment, an optical fiber guide rod 22 is provided on the top of the operating platform 7, and an optical fiber guide ring is provided on the top of the optical fiber guide rod 22. The detection optical fiber 21 passes through the optical fiber guide ring in an arc shape. The static bending radius of the detection optical fiber 21 is 10-15 times the outer diameter. The optical fiber guide rod 22 can bend the detection optical fiber 21 to a certain arc to avoid interference with optical fiber transmission.

[0033] An optical coupler mounting bracket 4 is provided on the top of the motor mounting bracket 8 near the linear motor 5. An optical coupler plate 3 is provided on the top of the optical coupler mounting bracket 4. An optical coupler shielding plate 23 is provided at one end of the lifting and fixing plate 20. The optical coupler shielding plate 23 is located above the optical coupler plate 3. The optical coupler plate 3 can realize the isolation transmission of electrical signals through optical signals, thereby protecting circuit safety and suppressing noise interference.

[0034] The bottom of the operating platform 7 is provided with a cuvette tank 11. A reference fiber 6 is provided on one side of the cuvette tank 11, and the end of the reference fiber 6 away from the cuvette tank 11 is connected to the optical unit 2. A reference signal plate assembly 12 is provided on the other side of the cuvette tank 11. The reference signal plate assembly 12 includes a lens barrel and a lens. During detection, a stable calibration solution can be added into the cuvette tank 11 to perform point-by-point correction within the weight range, generate a compensation equation, and ensure high accuracy of optical path control. A reference light shield 10 is provided on the top of the cuvette tank 11. The reference light shield 10 is connected to the cuvette tank 11 by magnetic attraction. The reference light shield 10 can block the light from the sample in the cuvette tank 11 to avoid interference from external light to the detection.

[0035] Furthermore, a guide rod 19 is provided on the top of the motor mounting bracket 8, and a guide hole is provided on the top of the lifting fixing plate 20. The guide rod 19 passes through the guide hole, and the lifting fixing plate 20 slides along the outer wall of the guide rod 19. The lifting fixing plate 20 can slide up and down along the guide rod 19 through the guide rod 19, which improves the stability of the movement of the sunshade 17.

[0036] It is worth mentioning that the linear motor 5 can change the optical path, which follows the Lambert-Beer law. The formula for changing the optical path is: A = ε * c * l, where A is the absorbance, ε is the molar absorptivity, c is the concentration, and l is the optical path. Changing the optical path enables precise measurement of samples with different concentrations. The linear motor 5 moves at intervals of 0.005 mm. This allows for minute changes in the optical path, effectively avoiding the focal point changes caused by moving the optical fiber or sensor position, ensuring that the light spot obtained by the receiver remains constant, thus achieving better measurement accuracy.

[0037] A method for using a high-precision in-situ ultraviolet-visible spectrophotometer includes the following steps: Step 1: Pour the high-concentration sample to be tested into the bottom-transmitting cuvette 15, and place the bottom-transmitting cuvette 15 into the movable stage 16; Step 2: Controlling the linear motor 5 will drive the lifting and fixing plate 20 to move up and down. The lifting and fixing plate 20 moves up and down, which in turn drives the light shield 17 to move up and down. The light shield 17 moves the sample, thereby changing the optical path. High-concentration samples will automatically reduce the optical path, while low-concentration samples will automatically increase the optical path. By continuously adjusting the optical path, the absorbance range will always be kept in the optimal measurement range. Step 3: The optical path change follows the linear relationship of Lambert-Beer's law, which can automatically correct for optical path differences. The same standard curve is applicable to sample measurements under different optical paths. Multiple optical paths can be automatically switched in a short time to measure the corresponding absorbance. With the optical path as the horizontal axis and the absorbance as the vertical axis, the slope of the fitted straight line can be obtained. According to Lambert-Beer's law, the concentration can be directly calculated without the need for a standard curve. The result can be obtained in one measurement.

[0038] Multi-path measurement: It automatically switches between multiple optical paths (such as L1, L2, L3) within a short period of time and measures the corresponding absorbance (A1, A2, A3).

[0039] Fitting slope: Plot the optical path length (L) on the horizontal axis and absorbance (A) on the vertical axis, and fit the slope of the straight line (ΔA / ΔL).

[0040] Concentration calculation: According to the Lambert-Beer law, the slope ΔA / ΔL = ε·c, and the concentration (c) can be directly calculated given ε.

[0041] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-precision in-situ ultraviolet-visible spectrophotometer, comprising a base shell (1), wherein an optical unit (2) is disposed on the inner bottom wall of the base shell (1), and a light source module and a monochromator are disposed inside the optical unit (2), characterized in that, The top of the optical unit (2) is fixedly connected to the operating platform (7) via a support rod (9). The top of the operating platform (7) is provided with a motor mounting bracket (8). The top of the motor mounting bracket (8) is provided with a linear motor (5). The output end of the linear motor (5) is connected to a lifting fixing plate (20). The lifting fixing plate (20) has a Z-shaped structure. The end of the lifting fixing plate (20) away from the linear motor (5) is connected to a light shield (17). The top of the light shield (17) is provided with a fiber optic clamp (18). The back of the optical unit (2) is provided with a detection fiber (21). The end of the detection fiber (21) away from the optical unit (2) is connected to the fiber clamp (18). The top outer wall of the operating platform (7) is provided with a movable stage (16). The movable stage (16) contains a bottom-transparent cuvette (15). The bottom-transparent cuvette (15) is made of transparent material and is located directly below the light shield (17). The bottom of the operating platform (7) is provided with a lens frame assembly (13). The lens frame assembly (13) includes a fixing box. The inner wall of the fixing box is provided with a lens mount. An optical lens is installed inside the lens mount. The lens frame assembly (13) contains a main signal board (14). The surface of the main signal board (14) is provided with an optical sensor and a microprocessor.

2. The in-situ ultraviolet-visible spectrophotometer with high measurement accuracy according to claim 1, characterized in that, The top of the operating platform (7) is provided with an optical fiber guide rod (22), and the top of the optical fiber guide rod (22) is provided with an optical fiber guide ring. The detection optical fiber (21) passes through the optical fiber guide ring in an arc shape, and the static bending radius of the detection optical fiber (21) is 10-15 times the outer diameter.

3. The in-situ ultraviolet-visible spectrophotometer with high measurement accuracy according to claim 1, characterized in that, The motor mounting bracket (8) is provided with an optical coupler mounting bracket (4) near the top of the linear motor (5). The top of the optical coupler mounting bracket (4) is provided with an optical coupler plate (3). One end of the lifting fixing plate (20) is provided with an optical coupler shielding plate (23), which is located above the optical coupler plate (3).

4. The in-situ ultraviolet-visible spectrophotometer with high measurement accuracy according to claim 1, characterized in that, The bottom of the operating platform (7) is provided with a cuvette groove (11), and a reference fiber (6) is provided on one side of the cuvette groove (11). The end of the reference fiber (6) away from the cuvette groove (11) is connected to the optical unit (2). A reference signal board assembly (12) is provided on the other side of the cuvette groove (11). The reference signal board assembly (12) includes a lens barrel and a lens.

5. The in-situ ultraviolet-visible spectrophotometer with high measurement accuracy according to claim 4, characterized in that, A reference light shield (10) is provided on the top of the cuvette tank (11), and the reference light shield (10) is connected to the cuvette tank (11) by magnetic attraction.

6. The in-situ ultraviolet-visible spectrophotometer with high measurement accuracy according to claim 1, characterized in that, The top of the motor mounting bracket (8) is provided with a guide rod (19), and the top of the lifting fixing plate (20) is provided with a guide hole. The guide rod (19) passes through the guide hole, and the lifting fixing plate (20) slides along the outer wall of the guide rod (19).

7. The in-situ ultraviolet-visible spectrophotometer with high measurement accuracy according to claim 1, characterized in that, The linear motor (5) can change the optical path, and the optical path change follows the Lambert-Beer law. The formula for the optical path change is: A=ε*c*l, where A is absorbance, ε is molar absorptivity, c is concentration, and l is optical path. Changing the optical path enables accurate measurement of samples with different concentrations.

8. The in-situ ultraviolet-visible spectrophotometer with high measurement accuracy according to claim 7, characterized in that, The moving interval of the linear motor (5) is 0.005 mm.

9. A method of using an in-situ ultraviolet-visible spectrophotometer with high measurement accuracy as described in claim 1, characterized in that, Includes the following steps: Step 1: Pour the high-concentration sample to be tested into a flat-bottomed transparent cuvette (15) and place the flat-bottomed transparent cuvette (15) into the moving stage (16); Step 2: Controlling the linear motor (5) will drive the lifting and fixing plate (20) to move up and down. The lifting and fixing plate (20) moves up and down, which in turn drives the light shield (17) to move up and down. The light shield (17) drives the sample to move, thereby changing the optical path. High-concentration samples will automatically reduce the optical path, while low-concentration samples will automatically increase the optical path. By continuously adjusting the optical path, the absorbance range will always be kept in the optimal measurement range. Step 3: The optical path change follows the linear relationship of Lambert-Beer's law, which can automatically correct for optical path differences. The same standard curve is applicable to sample measurements under different optical paths. Multiple optical paths can be automatically switched in a short time to measure the corresponding absorbance. With the optical path as the horizontal axis and the absorbance as the vertical axis, the slope of the fitted straight line can be obtained. According to Lambert-Beer's law, the concentration can be directly calculated without the need for a standard curve. The result can be obtained in one measurement.

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