Optical fiber device and method for detecting reducing sugar

Abstract

The invention discloses an optical fiber device for detecting reducing sugar, comprising a sample mixing reaction pool, a reflective mirror, an optical fiber / optical fiber bundle, an optical fiber laser and a spectrum analyzer; the sample mixing reaction pool has a sample inlet for a test liquid and a sample inlet for a reaction reagent; and a temperature control device is arranged in the sample mixing reaction pool; the reflective mirror is installed in the sample mixing reaction pool; one end of the optical fiber / optical fiber bundle is perpendicular to the reflective mirror, and the other end is respectively connected to the optical fiber laser and the spectrum analyzer through a coupler; there is a gap between one end of the optical fiber / optical fiber bundle perpendicular to the reflective mirror and the reflective mirror, and the gap is not greater than 0.02 mm. And a method for detecting reducing sugar is disclosed. The invention allows input signals and output signals to pass through the same optical fiber / optical fiber bundle through a vertical reflection mode, and by controlling the distance between the end face of the optical fiber / optical fiber bundle and the reflective mirror, the step of removing bubbles in the test process is avoided, and the invention is suitable for popularization and application in the detection of reducing sugar.

Description

Technical Field

[0001] The present invention relates to the field of analytical sensing technology, and more particularly to an optical fiber device and method for detecting reducing sugar. Background Art

[0002] The content of reducing sugar has a great influence on the morphology, organizational structure, physical and chemical properties, color, aroma, and taste of food. It is an important sign of the nutritional value of food and an important indicator of food quality. If the reducing sugar content in edible products is too high, it may cause the product to absorb moisture, become soft, and release water, and it may be storage-resistant and deteriorate; if the reducing sugar content is too low, it may cause small crystals to form before the edible product is formed and become hard, affecting the flavor and quality of the product itself, and affecting the fermentation process and the yield of the product. The content of reducing sugar can be used to understand the ratio of reducing sugar to non-reducing sugar components in food, providing a basis for the modulation and improvement of food flavor and the identification of the authenticity and quality of food. Therefore, the determination of reducing sugar content has important significance and practical value in the fields of microbial fermentation, biopharmaceuticals, biochemical engineering, starch sugar products, food and beverages, and various health products.

[0003] So far, researchers have designed many different devices to measure the content of reducing sugars in substances, mainly including UV-visible spectrophotometers, high-performance liquid chromatographs, ion chromatographs, atomic absorption spectrometers, etc., but all of them have some disadvantages. For example, the UV-visible spectrophotometer method has expensive instruments and equipment, cumbersome operation steps, a large amount of standard products required, and is greatly affected by external conditions, which is not conducive to industrial applications and the detection of a large number of samples; high-performance liquid chromatographs require the use of differential refractive index detectors, which have very strict environmental requirements, poor repeatability, and have the disadvantages of expensive instruments and equipment, low sensitivity, long system equilibration time, a large amount of standard products required, and being greatly affected by external conditions; atomic absorption spectrometers also have the disadvantages of expensive equipment and cumbersome operation. Moreover, the above methods for measuring the content of reducing sugars are all measured using the transmission mode, and the transmission mode method for measuring reducing sugars is difficult to avoid the influence of bubbles in the solution. Therefore, it is necessary to explore new ways to detect reducing sugars. Summary of the invention

[0004] In view of this, the present invention provides an optical fiber device and method for detecting reducing sugars, which allows input signals and output signals to pass through the same optical fiber / optical fiber bundle through a vertical reflection mode, thereby simplifying the complex design of a transmission mode.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] An optical fiber device for detecting reducing sugars, comprising a sample mixing reaction pool, a reflecting mirror, an optical fiber / optical fiber bundle, an optical fiber laser and a spectrum analyzer;

[0007] The sample mixing reaction pool has a sample inlet for the test liquid and a sample inlet for the reaction reagent; and a temperature control device is arranged in the sample mixing reaction pool;

[0008] The reflecting mirror is installed in the sample mixing reaction pool;

[0009] One end of the optical fiber / optical fiber bundle is perpendicular to the reflective mirror, and the other end is connected to the optical fiber laser and the spectrum analyzer through a coupler;

[0010] There is a gap between one end of the optical fiber / optical fiber bundle perpendicularly facing the reflective mirror and the reflective mirror, and the gap is no greater than 0.02 mm.

[0011] The temperature control device is used to adjust the temperature of the mixed liquid of the test liquid and the reaction reagent, so as to make the reducing sugar in the test liquid react. The detection can be carried out after the reaction is completed. One end of the optical fiber / optical fiber bundle is perpendicular to the reflective mirror surface, and a certain gap is left between the mirror surface. After the optical fiber laser outputs the light signal, the light is transmitted from one end of the optical fiber / optical fiber bundle, transmitted to the reflective mirror surface through the reaction liquid in the gap, and then transmitted back to the optical fiber / optical fiber bundle through the reaction liquid after vertical reflection. The device is simple in design and easy to operate, and is suitable for promotion and application in the detection of reducing sugars.

[0012] Preferably, a stirring device is installed in the sample mixing reaction pool to promote the full mixing of the test liquid and the reaction reagent, thereby making the reaction faster and more complete.

[0013] Preferably, the stirring device is a magnetic stirrer.

[0014] Preferably, the optical fiber device for detecting reducing sugars further comprises a first flow injection pump and a second flow injection pump;

[0015] The first flow injection pump is used to pump the test liquid from the test liquid inlet into the sample mixing reaction pool;

[0016] The second flow injection pump is used to pump the reaction reagent from the reaction reagent injection port into the sample mixing reaction pool.

[0017] The setting of the flow injection pump makes the detection process highly automated and ensures the accuracy of the injection.

[0018] Preferably, the temperature control device comprises a constant temperature control device with a temperature sensor, which adjusts the temperature according to a preset temperature while detecting the temperature of the mixed liquid in the sample mixing reaction pool.

[0019] Preferably, the sample mixing reaction pool is provided with a waste liquid discharge port.

[0020] A method for detecting reducing sugars, using an optical fiber / optical fiber bundle direct vertical reflection mode, so that incident light and reflected light are transmitted and feedback information through the same optical fiber / optical fiber bundle channel; a test liquid reacts with a reaction reagent to obtain a reaction liquid, and an optical signal transmission path passes through the reaction liquid; the reducing sugar content in the test liquid is judged according to the reflected light intensity, color depth, optical density, resonance wavelength or phase.

[0021] Preferably, the detection using the above device comprises the following steps:

[0022] (1) Clean the sample mixing reaction pool and the pipeline channels used for sampling;

[0023] (2) introducing the test solution and the reaction reagent into the sample mixing reaction pool through the test solution injection port and the reaction reagent injection port respectively and mixing them thoroughly;

[0024] (3) adjusting the temperature by a temperature control device so that the test liquid reacts with the reaction reagent;

[0025] (4) The optical signal emitted by the fiber laser is transmitted through the optical fiber / fiber bundle, vertically reflected by the reflective mirror and then transmitted back to the optical fiber / fiber bundle, and the spectrum analyzer receives the feedback signal;

[0026] (5) analyzing the reducing sugar content in the test solution based on the reflected light intensity, color depth, optical density, resonant wavelength or phase information received by the spectrum analyzer and comparing it with the linear curve of the standard solution;

[0027] (6) after the detection, the reaction solution is removed from the sample mixing reaction pool;

[0028] (7) Rinse the sample mixing reaction pool and the pipe channels used for sample injection thoroughly with deionized water;

[0029] (8) Follow steps (2) to (5) to test the next sample.

[0030] Preferably, the reaction reagent is a reagent capable of reacting with reducing sugars, including two or more of sodium hydroxide, copper sulfate, methylene blue, concentrated sulfuric acid, crystalline phenol, potassium permanganate, potassium ferrocyanide, 3,5-dinitrosalicylic acid, glycerol, ferric sulfate, hydrochloric acid, methyl red, ethanol, copper tartrate, potassium sodium tartrate, and sodium sulfite.

[0031] Preferably, the reflective mirror material includes one or more of gold, silver, aluminum, titanium dioxide, zirconium dioxide and platinum, which is used for reflecting light signals.

[0032] Preferably, the surface of the reflective mirror is coated with a polymer transparent nano film with a thickness of 10nm-100μm, which can effectively avoid corrosion of the reflective mirror caused by chemical reactions, thereby ensuring the accuracy of the measurement results.

[0033] As can be seen from the above technical solution, the present invention adopts a direct vertical reflection mode, so that the input signal and the outgoing signal pass through the same optical fiber or the same optical fiber bundle, which simplifies the complex design of the transmission mode and effectively reduces the manufacturing cost of the device. By controlling the distance between the end face of the optical fiber or optical fiber bundle and the reflective mirror, the step of removing bubbles during the test process is avoided, and reducing sugar can be measured in real time without cooling and removing bubbles, which simplifies the assembly procedure and shortens the detection time. It has broad commercial application prospects in the fields of food safety, industrial fermentation, and microbial product analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Shown is a schematic diagram of the structure of the device of the present invention;

[0035] In the figure: 1. fiber laser, 2. coupler, 3. fiber bundle, 4. first flow injection pump, 5. second flow injection pump, 6. test liquid injection port, 7. reaction reagent injection port, 8. sample mixing reaction pool, 9. reflecting mirror, 10. waste liquid discharge port, 11. magnetic stirrer, 12. temperature control device, 13. spectrum analyzer, 14. computer.

[0036] Figure 2 It is a linear curve of reducing sugar concentration and resonance wavelength.

[0037] Figure 3 It is a linear curve of reducing sugar concentration and standardized color value.

[0038] Figure 4 It is a linear curve of reducing sugar concentration and light intensity signal. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Example 1

[0041] like Figure 1 As shown, a fiber optic device for detecting reducing sugars includes a sample mixing reaction pool 8, a reflecting mirror 9, a fiber optic bundle 3, a fiber optic laser 1 and a spectrum analyzer 13.

[0042] The sample mixing reaction pool 8 has a test liquid injection port 6 and a reaction reagent injection port 7 at the top, and a waste liquid discharge port 10 (equipped with a valve or a plug) at the bottom on one side;

[0043] The first flow injection pump 4 pumps the test liquid from the test liquid inlet 6 into the sample mixing reaction pool 8;

[0044] The second flow injection pump 5 pumps the reaction reagent from the reaction reagent injection port 7 into the sample mixing reaction pool 8 .

[0045] A magnetic stirrer 11 and a temperature control device 12 are provided in the sample mixing reaction pool 8; the temperature control device 12 can be connected to a computer 14, and the computer 14 issues temperature control instructions.

[0046] The reflective mirror 9 is made of platinum with a thickness of 1 mm, and the surface is coated with a polytetrafluoroethylene polymer transparent nano film with a thickness of 100 nm; the reflective mirror 9 is embedded on one side wall of the sample mixing reaction pool 8 .

[0047] The optical fiber bundle 3 is composed of 50 optical fibers; one end is perpendicular to the reflective mirror 9, with a gap of 0.01 mm between the reflective mirror 9; the other end is connected to the optical fiber laser 1 and the spectrum analyzer 13 through the coupler 2.

[0048] The spectrum analyzer 13 can be connected to the computer 14, and the computer 14 can be used to analyze the feedback information.

[0049] The detection using the above device includes the following steps:

[0050] (1) Cleaning the sample mixing reaction pool 8 and the pipeline channels used for sample injection (including the pipeline between the first flow injection pump 4 and the sample liquid injection port 6, and the pipeline between the second flow injection pump 5 and the reaction reagent injection port 7);

[0051] (2) using the first flow injection pump 4 and the second flow injection pump 5 to respectively introduce the test liquid and the reaction reagent into the sample mixing reaction pool 8 through the test liquid injection port 6 and the reaction reagent injection port 7; under the action of the magnetic stirrer 11, the test liquid and the reaction reagent are fully mixed;

[0052] (3) adjusting the temperature by the temperature control device 12 so that the liquid to be tested reacts with the reaction reagent;

[0053] (4) The optical signal emitted by the fiber laser 1 is transmitted through the optical fiber bundle 3, and then vertically reflected by the reflective mirror 9 and transmitted back to the optical fiber bundle 3, and the optical spectrum analyzer 13 receives the feedback signal;

[0054] (5) analyzing the reducing sugar content in the test liquid according to the information received by the spectrum analyzer 13;

[0055] (6) After the detection, the reaction liquid is removed from the sample mixing reaction pool 8 through the waste liquid discharge port 10;

[0056] (7) The sample mixing reaction pool 8 and the pipe channel used for sample injection are fully rinsed with deionized water by driving the first flow injection pump 4 and the second flow injection pump 5;

[0057] (8) Follow steps (2) to (5) to test the next sample.

[0058] Example 2

[0059] The reducing sugar sample solution extracted from wheat flour was measured using the device in Example 1:

[0060] (1) flushing the sample mixing reaction pool 8 and the pipe channel used for sample injection with acetone, ethanol, and water in sequence;

[0061] (2) Under the action of the first flow injection pump 4, 5 ml of the reducing sugar sample solution is injected into the sample mixing reaction pool 8 through the test solution injection port 6; under the action of the second flow injection pump 5, 2.5 ml of a reaction reagent containing 0.27 M copper sulfate pentahydrate, 2.5 μL of concentrated sulfuric acid, 1.23 M potassium sodium tartrate and 2.5 M sodium hydroxide is injected into the sample mixing reaction pool 8 through the reaction reagent injection port 7; under the action of the magnetic stirrer 11, the reducing sugar sample solution and the reaction reagent are fully mixed in the sample mixing reaction pool 8;

[0062] (3) The computer 14 controls the temperature control device 12 to adjust the temperature so that the temperature of the mixed liquid in the sample mixing reaction pool 8 reaches 100° C., the substances in the mixed liquid react, and the reaction is terminated when the temperature is kept at 100° C. for 5 minutes;

[0063] (4) After the reaction is completed, the optical signal emitted by the fiber laser 1 is transmitted through the optical fiber bundle 3, and then vertically reflected by the reflective mirror 9 and transmitted back to the optical fiber bundle 3, and the optical spectrum analyzer 13 receives the feedback resonant wavelength signal;

[0064] (5) Processing the data using computer 14: According to the resonant wavelength of 587.33 nm received by the spectrum analyzer 13, the linear curve ( Figure 2 , using different concentrations of reducing sugar standard solutions as samples and tested according to the above method) as a control, the reducing sugar content was calculated to be 22.8%.

[0065] Example 3

[0066] The reducing sugar sample solution extracted from potatoes was measured using the device in Example 1:

[0067] (1) flushing the sample mixing reaction pool 8 and the pipe channel used for sample injection with acetone, ethanol, and water in sequence;

[0068] (2) Under the action of the first flow injection pump 4, 5 ml of the reducing sugar sample solution is injected into the sample mixing reaction pool 8 through the test solution injection port 6; under the action of the second flow injection pump 5, 5 ml of a reaction reagent containing 0.028 M 3,5-dinitrosalicylic acid, 0.650 M sodium hydroxide and 75 μL glycerol is injected into the sample mixing reaction pool 8 through the reaction reagent injection port 7; under the action of the magnetic stirrer 11, the reducing sugar sample solution and the reaction reagent are fully mixed in the sample mixing reaction pool 8;

[0069] (3) The computer 14 controls the temperature control device 12 to adjust the temperature so that the temperature of the mixed liquid in the sample mixing reaction pool 8 reaches 100° C., the substances in the mixed liquid react, and the temperature is kept at 100° C. for 10 minutes;

[0070] (4) The optical signal emitted by the fiber laser 1 is transmitted through the optical fiber bundle 3, and then vertically reflected by the reflective mirror 9 and transmitted back to the optical fiber bundle 3, and the optical spectrum analyzer 13 receives the feedback signal;

[0071] (5) The computer 14 is used to process the light color depth data: the standardized color value received and fed back by the spectrum analyzer 13 is 0.1601, which is consistent with the linear curve of the standard sample ( Figure 3 , using different concentrations of reducing sugar standard solutions as samples and tested according to the above method) as a control, the reducing sugar content was calculated to be 12.8%.

[0072] Example 4

[0073] The reducing sugar sample solution extracted from strawberries was measured using the device in Example 1:

[0074] (1) flushing the sample mixing reaction pool 8 and the pipe channel used for sample injection with acetone, ethanol, and water in sequence;

[0075] (2) Under the action of the first flow injection pump 4, 5 ml of the reducing sugar sample solution is injected into the sample mixing reaction pool 8 through the test solution injection port 6; under the action of the second flow injection pump 5, 10 ml of a reaction reagent containing 0.0276 M 3,5-dinitrosalicylic acid, 0.524 M sodium hydroxide, 0.655 M potassium sodium tartrate, 0.0531 M crystalline phenol and 0.0396 M sodium sulfite is injected into the sample mixing reaction pool 8 through the reaction reagent injection port 7; under the action of the magnetic stirrer 11, the reducing sugar sample solution and the reaction reagent are fully mixed in the sample mixing reaction pool 8;

[0076] (3) The computer 14 controls the temperature control device 12 to adjust the temperature so that the temperature of the mixed liquid in the sample mixing reaction pool 8 reaches 100° C., the substances in the mixed liquid react, and the temperature is kept at 100° C. for 6 minutes;

[0077] (4) The optical signal emitted by the fiber laser 1 is transmitted through the optical fiber bundle 3, and then vertically reflected by the reflective mirror 9 and transmitted back to the optical fiber bundle 3, and the optical spectrum analyzer 13 receives the feedback information;

[0078] (5) The light intensity signal data is processed by computer 14: According to the light intensity signal received and fed back by spectrum analyzer 13, it is 5465 a.u., which is consistent with the linear curve of standard sample ( Figure 4 , using different concentrations of reducing sugar standard solutions as samples and tested according to the above method) as a control, the reducing sugar content was calculated to be 5.86%.

[0079] The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. An optical fiber device for detecting reducing sugars, characterized in that: The invention comprises a sample mixing reaction pool, a reflective mirror, an optical fiber / optical fiber bundle, an optical fiber laser and a spectrum analyzer; the sample mixing reaction pool has a sample inlet for a test liquid and a sample inlet for a reaction reagent; and a temperature control device is arranged in the sample mixing reaction pool; the reflective mirror is installed in the sample mixing reaction pool; one end of the optical fiber / optical fiber bundle is perpendicular to the reflective mirror, and the other end is connected to the optical fiber laser and the spectrum analyzer respectively through a coupler; there is a gap between the end of the optical fiber / optical fiber bundle perpendicular to the reflective mirror and the reflective mirror, and the gap is not greater than 0.02 mm; A stirring device is installed in the sample mixing reaction pool; It also includes a first flow injection pump and a second flow injection pump; the first flow injection pump is used to pump the test liquid from the test liquid injection port into the sample mixing reaction pool; the second flow injection pump is used to pump the reaction reagent from the reaction reagent injection port into the sample mixing reaction pool.

2. The optical fiber device for detecting reducing sugar according to claim 1, characterized in that: The temperature control device includes a thermostatic control device with a temperature sensor.

3. The optical fiber device for detecting reducing sugar according to claim 1, characterized in that: The sample mixing reaction pool is provided with a waste liquid discharge port.

4. An optical fiber device for detecting reducing sugar according to any one of claims 1 to 3, characterized in that: The method for detecting reducing sugar using the optical fiber device comprises the following steps: (1) Clean the sample mixing reaction pool and the pipeline channels used for sampling; (2) introducing the test solution and the reaction reagent into the sample mixing reaction pool through the test solution injection port and the reaction reagent injection port respectively and mixing them thoroughly; (3) adjusting the temperature by a temperature control device so that the test liquid reacts with the reaction reagent; (4) The optical signal emitted by the fiber laser is transmitted through the optical fiber / fiber bundle, vertically reflected by the reflective mirror and then transmitted back to the optical fiber / fiber bundle, and the spectrum analyzer receives the feedback signal; (5) analyzing the reducing sugar content in the test solution based on the reflected light intensity, color depth, optical density, resonant wavelength or phase information received by the spectrum analyzer and comparing it with the linear curve of the standard solution; (6) after the detection, the reaction solution is removed from the sample mixing reaction pool; (7) Rinse the sample mixing reaction pool and the pipe channels used for sample injection thoroughly with deionized water; (8) Follow steps (2) to (5) to test the next sample.

5. The optical fiber device for detecting reducing sugar according to claim 4, characterized in that: The reaction reagent is a reagent that can react with reducing sugars, including two or more of sodium hydroxide, copper sulfate, methylene blue, concentrated sulfuric acid, crystalline phenol, potassium permanganate, potassium ferrocyanide, 3,5-dinitrosalicylic acid, glycerol, ferric sulfate, hydrochloric acid, methyl red, ethanol, copper tartrate, potassium sodium tartrate, and sodium sulfite.

6. The optical fiber device for detecting reducing sugar according to claim 4, characterized in that: The reflective mirror material includes one or more of gold, silver, aluminum, titanium dioxide, zirconium dioxide and platinum, and is used for reflecting light signals.

7. The optical fiber device for detecting reducing sugar according to claim 6, characterized in that: The surface of the reflective mirror is plated with a polymer transparent nano film.

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