Gelling time determinator and method based on light scattering effect

Abstract

The invention discloses a gelling time tester and method based on a light scattering effect. The gelling time tester comprises a laser light source, a light chopper, a first condensing lens, a second condensing lens, a sample carrier, a light sensor and a controller, the laser light source is used for generating incident light; the light chopper is used for converting incident light into alternating sample light and reference light in different directions; the reference light is projected into the light sensor through the first condensing lens; the sample light is projected to sol loaded in a certain sample tube of the sample carrier, and scattered light is formed; the second condensing lens is fixed on a path which forms an included angle with the sample light, and the scattered light is projected into the light sensor through the second condensing lens; the light sensor is connected with the upper computer; and the controller is connected with the laser light source and the upper computer. The gelation time tester adopts a reference light design, so that measurement errors caused by fluctuation of light source signals can be effectively prevented.

Description

Technical Field

[0001] The invention relates to the field of gel time measurement, and in particular to a gel time measuring instrument and method based on light scattering effect. Background Art

[0002] The time required for certain solutions to transform from a highly fluid liquid to a completely non-flowing gel under appropriate conditions is called gelation time. Gelation time is an important parameter. The determination of gelation time is used in industry, construction, materials, biology, chemical industry and other fields. There is also a need to determine gelation time in scientific research and experimental teaching. At present, there are two methods for measuring the gelation time of gels, the visual method and the gelation time measuring instrument method based on a viscometer. The former measures the time when the sample to be gelled is completely non-flowable by manual and constant observation. The visual method is obviously subjective and has large measurement errors. The latter is a more accurate measurement method. The liquid sample is placed in a container and a standard rotor is driven to rotate in the liquid sample under rated torque. As the degree of sample gelation increases, the viscosity increases and the rotor speed decreases. When the viscosity increases to a certain value, the rotor stops rotating and the time when gelation occurs is recorded. This method can quantitatively measure the gel time, but it has several disadvantages. It requires a stirrer or a stirring rod. Some samples need to be tested for gel time without disturbance, and these samples cannot be tested using this instrument. Batch testing is not possible, and one instrument can only test one sample. The price of a single machine is expensive, generally more than RMB 50,000.

[0003] Light scattering refers to the phenomenon that a portion of light deviates from its original propagation direction when passing through an inhomogeneous medium. The main component of scattered light is Rayleigh scattering, and its intensity can be calculated according to the Rayleigh light scattering formula. The larger the particle size of the dispersed phase, the stronger the Rayleigh scattering.

[0004] Patent document 1 (Japanese Patent No. 3199850) uses a laser light source to irradiate a blood sample. When platelets aggregate, the size and number of platelet aggregates change. The detector receives the 90-degree lateral scattered light of the platelets and determines the size and number of the platelet aggregates based on the results.

[0005] Patent document 2 (Japanese Patent Laid-Open No. 2004-93536) uses a gelation reaction measuring device using turbidimetric time analysis to measure the change in the intensity of transmitted light of a mixture of a sample and a horseshoe crab reagent over time, and determines the endotoxin concentration of the sample based on the change within a specified time.

[0006] Patent Documents 1 and 2 require a reaction time of about 90 minutes at low concentrations to generate aggregates. That is, although the gelation time of the reaction solution is proportional to the concentration of the target substance in the sample, the correct gelation start time cannot be detected due to sensitivity limitations, so the reaction amount can only be calculated based on the gelation end time, using the gelation time as a reference.

[0007] Patent 3 (application number 200980107268.2) describes a gel particle measuring device for measuring the time when gel particles appear through gelation reaction. The principle is that endotoxin or β-D-glucan does not gel when stirred. When the horseshoe crab reagent is added, the horseshoe crab reagent gels it. The gelation speed is related to the concentration of the test object. The generation state of gel particles is inferred by measuring the intensity change of the transmitted light. The time when the transmitted light changes from the stable state is the time when the gel particles appear.

[0008] Patent 4 application number 200680055919.4 provides a gelation reaction measuring device and a test kit, the reaction device can measure the concentration of endotoxin or β-D-glucan through gelation reaction with high sensitivity in a short time. The principle is to use laser to irradiate a solution containing the target substance and a gelation reagent, and under stirring, the solution generates gel particles, which scatter the incident laser, and the scattered light is detected by a photodiode array, and the diameter and number of the generated gel particles are tested in time series by computer processing.

[0009] The above-mentioned testing devices all have the following problems: the absolute value of transmitted or scattered light is used as the test basis, and the signal fluctuation of the light source itself or the background change will lead to large test errors; only a single sample can be measured, which is inefficient; the light source is always turned on during operation, has a short life and high energy consumption. Summary of the invention

[0010] The present invention aims to provide a gel time measuring instrument and measuring method based on light scattering effect, so as to solve at least one of the above-mentioned existing problems.

[0011] To this end, the specific technical solution adopted by the present invention is as follows:

[0012] According to a first aspect of the present invention, a gel time measuring instrument based on light scattering effect is provided, comprising a laser light source, a light cutter, a first condensing lens, a second condensing lens, a sample carrier, a light sensor and a controller;

[0013] The laser light source is used to generate incident light;

[0014] The optical chopper is used to convert the incident light into sample light and reference light that are alternately and in different directions;

[0015] The reference light is projected into the photoreceptor through a first condenser lens;

[0016] The sample carrier is provided with at least one socket for placing a sample tube; the sample light is projected onto the sol in a sample tube loaded in the sample carrier and forms scattered light;

[0017] The second condenser lens is fixed on a route that forms a certain angle with the sample light, and the scattered light is projected into the photoreceptor through the second condenser lens;

[0018] The photosensitive device is connected to a host computer to upload data of reference light and sample light;

[0019] The controller is connected to the laser light source and a host computer and is used to receive instructions from the host computer and configure light source parameters of the laser light source.

[0020] Furthermore, the incident light is pulsed laser.

[0021] Furthermore, the light cutter is a rotating fan-shaped mirror, which includes four fan-shaped parts: a reflector, a transmission mirror and two backgrounds, and the backgrounds are neither transmitting nor reflecting; the reflector and the transmission mirror are spaced by the backgrounds.

[0022] Furthermore, the rotating sector mirror is divided into four sector-shaped parts with equal areas.

[0023] Furthermore, the sample carrier is a turntable, which rotates under the control of the controller, and the sockets are distributed on the turntable in a circular array; the sample carrier is located at a certain position on the sample light path as a test position, and the sample tube is switched to the test position of the sample carrier by rotating the sample carrier.

[0024] Furthermore, the second condensing lens is fixed at a path that is 45 degrees to the sample light.

[0025] Furthermore, the laser light source is a pulse light source, and the incident light generated is blue light with a wavelength of 445nm and a power of 5-50mW; or green light with a wavelength of 532nm and a power of 5-50mW.

[0026] Furthermore, the photosensor is a photomultiplier tube.

[0027] According to a first aspect of the present invention, a method for measuring gel time based on light scattering effect is provided, using the gel time measuring instrument based on light scattering effect as described above, comprising the following steps:

[0028] Run the test software on the host computer to set the laser pulse cycle, the constant light time of each laser pulse cycle, the signal ratio threshold and the change rate threshold;

[0029] Control the laser light source to emit pulsed laser according to a set period;

[0030] Receive data from the photosensitive sensor, record the average intensity of the scattered light and the average intensity of the reference light in each cycle; calculate the signal ratio of each cycle, and judge whether the gel is complete according to the gel time judgment standard. If so, stop the test and record the time of the previous cycle as the gel time. If not, continue the test until the gel is complete or the condition for forcibly ending the test is triggered, and display the test results on the terminal; the signal ratio is: the ratio of the average intensity of the scattered light in each laser pulse cycle to the average intensity of the reference light; the gel time judgment standard is: the signal ratio exceeds the signal ratio threshold, and the rate of change of the signal ratio is within the rate of change threshold; the condition for forcibly ending the test is: the test duration exceeds the maximum test time but the signal ratio is still less than the signal ratio threshold.

[0031] Furthermore, the method also includes a sample carrier control step: controlling the rotation speed of the turntable of the sample carrier so that the laser light source of any sample tube is always in a constantly on state when passing through the test position.

[0032] The present invention adopts the above technical solution to achieve the following beneficial effects:

[0033] In a specific embodiment, the reference light design is adopted to effectively prevent the measurement error caused by the fluctuation of the light source signal itself.

[0034] In a specific embodiment, the sample carrier adopts a turntable design, which can test multiple samples at one time, realizing batch sample measurement with higher efficiency.

[0035] In a specific embodiment, the laser light source adopts a pulsed laser design, which can significantly increase the service life of the light source and reduce energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] To further illustrate the various embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, a person of ordinary skill in the art should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0037] Figure 1 is a functional block diagram of the gel time measuring instrument of the present invention;

[0038] Figure 2 is a schematic diagram of a light cutter of the present invention;

[0039] Figure 3 is a 3D rendering of the sample carrier of the present invention;

[0040] Figure 4 Theoretical criteria for determining gel time;

[0041] Figure 5 The actual standard for judging gel time;

[0042] Figure 6 It is a schematic diagram of the full cycle and constant light duration. DETAILED DESCRIPTION

[0043] The present invention will now be further described with reference to the accompanying drawings and specific implementation methods.

[0044] When light passes through a sample, the scattered light increases due to the increase in the degree of gelation. When the gel stops growing, the scattered light intensity remains basically unchanged. The present invention uses this principle to design a gelation time measuring instrument.

[0045] like Figure 1 As shown, the present invention provides an embodiment of a gel time measuring instrument based on light scattering effect, which is mainly composed of a laser light source 1, a light cutter 2, a focusing lens 4, a sample carrier 3, a photosensor 5, a focusing lens 6, a controller 7 and a computer 8.

[0046] In this embodiment, the laser light source 1 can use the light source of an ordinary laser pen to reduce costs, and preferably use blue light with a wavelength of 445nm (power 5-50 milliwatts) or green light with a wavelength of 532nm (power 5-50 milliwatts). The wavelength of the laser is blue light < green light < red light. According to the Rayleigh light scattering formula, the intensity of scattered light is inversely proportional to the fourth power of the wavelength. To increase the signal strength, the laser color priority is blue light > green light > red light. The light source adopts a pulse design, and the pulse period and the irradiation time of each period can be adjusted by the controller 7 to reduce energy consumption and increase the service life of the light source.

[0047] like Figure 2 As shown, in this embodiment, the optical cutter 2 is a rotating fan-shaped mirror, which is divided into four parts, 1 / 4 is a reflective mirror (marked as R in the figure), 1 / 4 is a transmission mirror (marked as T in the figure), and the rest is a background that neither transmits nor reflects (marked as B in the figure). When the fan-shaped mirror rotates, when the reflective mirror enters the light path, the incident light S1 is reflected to generate reference light S3; when the transmission mirror enters the light path, the incident light S1 is transmitted to generate sample light S2; when the background part enters the light path, the incident light S1 is almost completely absorbed. By rotating, the optical cutter 2 converts the incident light S1 of the laser light source 1 into two alternating beams of light: reference light S3 and sample light S2, which pass through different paths and finally arrive at the photoreceptor 5 at different times. Even if the light source fluctuates or the background noise changes, the reference light and the sample light also change synchronously, and the ratio between the two is stable and unchanged, which can effectively offset the negative effects of light source fluctuations, stray light, background noise, etc.

[0048] The condenser lens 4 and the condenser lens 6 are used to converge the sample light S2 and the reference light S3, respectively, to increase the intensity of the light entering the photoreceptor 5. The condenser lens 6 is fixed in the direction of the reference light S3, and the condenser lens 4 is fixed at a 45-degree route with the sample light S2. According to the Rayleigh light scattering formula, the intensity of scattered light is related to the scattering angle. When the scattering angle is 0 or 180 degrees, the intensity is the highest, and when it is 90 degrees, the intensity is the lowest. However, if it is designed to be 0 or 180 degrees, the transmitted light (i.e., the sample light S2) will produce strong interference. Therefore, preferably, the scattering angle is 45 degrees to avoid the interference of the transmitted light while maintaining a medium-intensity scattering signal intensity.

[0049] like Figure 3 As shown, an embodiment of a sample carrier 3 is given. In this embodiment, the sample carrier 3 includes a turntable with a socket and a motor. The turntable is connected to the motor, and there are 8 sockets on the surface of the turntable, which can load up to 8 sample tubes at one time. Under the action of the motor, the sample tubes loaded on the turntable can be transferred to the test position. At the test position, the sample light S2 will irradiate the sol in the sample tube to form scattered light S4. The turntable has a diameter of 10 cm. In order to prevent corrosion by the sample, the turntable is preferably made of polytetrafluoroethylene; the motor can be controlled by a controller to drive the turntable to rotate at a specified speed. The sample tube is used to hold the sample solution. In order to increase the intensity of the scattered light S4 as much as possible while meeting the mechanical strength, a highly light-transmitting material such as glass or quartz is used. In this embodiment, the diameter of the sample tube is 1 cm, the wall thickness is 0.5 mm, and the tube height is 5 cm. The sample tubes are loaded on the socket of the turntable, and 1-8 tubes can be loaded according to actual needs. Figure 3 The effect of loading 4 sample tubes is depicted. The sample carrier 3 of this embodiment can be used to perform batch sample testing, and the sample light and the scattered light are at an angle of 45 degrees, and the plane formed is parallel to the horizontal plane.

[0050] The photoreceptor 5 is used to receive the signals of the reference light S3 and the sample light S2. Through the optical path design, condensing lenses 4 and 6 are arranged on the optical paths of the reference light S3 and the scattered light S13, so that the reference light S3 and the scattered light S4 can be focused on the same photoreceptor 5. The photoreceptor 5 preferably adopts a photomultiplier tube, which can greatly increase the signal strength.

[0051] In this embodiment, the computer 8 is a desktop or notebook computer with a Windows operating system, which needs to be connected to the measuring instrument with a data cable and installed with a matching program, which has the functions of adjusting sample test parameters, controlling the test process, and outputting test results. In specific applications, the computer is also integrated into the measuring instrument in the form of a board card, and the corresponding test program is written to achieve stand-alone operation.

[0052] The controller 7 is an embedded single chip microcomputer, which can receive computer instructions and control the light source parameters of the laser light source, the rotation frequency of the light cutter, the rotation of the sample carrier, the position of the sample tube, etc.

[0053] Working principle:

[0054] The gelation time measuring instrument is based on the Rayleigh scattering principle and determines the degree of gelation according to the change in the intensity of scattered light. During the gel formation process, the particle size increases and the scattered light increases. When the gel stops growing, the scattered light intensity remains basically unchanged. The gelation time is obtained through the turning point from the change to the unchanged scattered light signal.

[0055] Rayleigh light scattering formula:

[0056]

[0057] I, I0: Intensity of scattered light and incident light

[0058] λ: wavelength of incident light

[0059] V: volume of a single particle

[0060] c: Particle concentration (number of colloid particles per unit volume of sol)

[0061] n0, n: refractive index of the dispersion medium and the dispersed phase

[0062] This gel time tester can perform single sample testing and batch sample testing, as shown below:

[0063] Example 1: Single sample test

[0064] 1. Gel time judgment standard

[0065] When the sample is in a solution state, the scattered light intensity is very low, and the ratio of the average intensity of the scattered light to the average intensity of the reference light in each laser pulse cycle (referred to as the signal ratio, represented by C) is almost 0. As the gel reaction proceeds, the number and size of the gel particles gradually increase, the scattered light gradually increases, and the reference light remains unchanged, so C gradually increases. When the gel reaction is complete, the number and size of the gel particles remain stable, the scattered light remains stable, and C also remains stable. Therefore, the time corresponding to the turning point from the change of C to the unchanged state is the gelation time, such as Figure 4 In actual operation, when the gel reaction is complete, C will fluctuate within a certain range. Therefore, the criterion for judging the gelation time is that C is strong enough, that is, it exceeds the signal ratio threshold (denoted by C m The signal ratio is expressed as B m Indicates) Figure 5 As shown, points a and b represent two consecutive signal ratios, each of which is greater than the signal ratio threshold C.m , and |ΔC / Ca|≤B m , then the time at point a is the gel time.

[0066] 2. Set test parameters

[0067] Set the test parameters in the software, including the full cycle of the pulse laser (default value 1s), the constant light duration of each cycle (default value 0.1s), the turntable speed (indicated by r, default value 0), the maximum test time (indicated by t m Indicates, the default value is 60 minutes), signal ratio threshold C m (default value 0.05) and change rate threshold B m (Default value 5%), etc. The above parameters can be adjusted according to actual needs. For example, if the predicted gel time exceeds 30 minutes, the pulse cycle time can be increased; if the gel time is less than 5 minutes, the pulse cycle time can be decreased. For details on the relationship between the pulse cycle and the constant light duration, see Figure 6 For a single sample, the turntable speed should be set to 0. Maximum test time t m Used to limit the test duration. If the test duration exceeds t m But C is still smaller than C m , the gelation time of the sample may be very long. In order to protect the instrument, the test is forcibly ended.

[0068] 3. Sample Preparation

[0069] The gel that can be tested includes any inorganic gel and organic gel resin. As long as the gel particle size is between 10nm and 100nm, it can be used as a test object. The solution to be tested is mixed evenly in advance, and the time is recorded, which is the starting point of the gel reaction. The solution is loaded into a sample tube, and the loading amount is between half and three quarters of the sample tube capacity. As long as it is within this range, the amount of loading does not affect the test results. Load the sample tube in the test position, that is, Figure 1 The No. 1 position.

[0070] 4. Sample testing

[0071] The test begins. The light source emits pulsed lasers at a specified cycle and records the average intensity of scattered light and the average intensity of reference light in each cycle. The C of each cycle is calculated and the gelation time is used to determine whether the gel is complete. If so, the test is stopped and the time of the previous cycle is recorded as the gelation time. If not, the test is continued until the gel is complete or the conditions for forcibly ending the test are triggered (the test time exceeds t m But C is still smaller than C m ) and display the test results in the terminal.

[0072] Example 2: Batch sample testing

[0073] 1. Gel time judgment standard

[0074] Exactly the same as Example 1

[0075] 2. Set test parameters

[0076] In this embodiment, the turntable speed is set to rotate 1 circle per second, and the sample tubes on the turntable will circulate and pass through the test position in sequence. By reasonably setting the full cycle and constant light duration (compared with embodiment 1, the constant light duration should be appropriately increased and the full cycle should be appropriately shortened), the light source of any sample tube is always on when passing through the test position. Other test parameters are the same as implementation plan 1.

[0077] 3. Sample Preparation

[0078] In this embodiment, there are 8 sockets on the turntable, that is, a maximum of 8 sample tubes can be placed. Preferably, the sample tubes can be placed in a continuous or uniform arrangement so as to match the constant light duration and full cycle of the test parameters, so that the light source is always in a constant light state when the sample tube passes through the test position. Others are the same as the first embodiment.

[0079] 4. Sample testing

[0080] According to the experimental scheme 1, the gelation time of each sample tube is determined until all sample tubes are tested or the conditions for forcibly ending the test are triggered (the test time exceeds t m But C is still smaller than C m ), and the test results of each sample tube are displayed on the terminal.

[0081] The gel time measuring instrument of this embodiment adopts a reference light design, which can effectively prevent measurement errors caused by fluctuations in the light source signal itself; the sample carrier adopts a turntable design, which can perform single sample and batch sample measurements with higher efficiency; the laser light source adopts a pulse light source design, which can significantly increase the service life of the light source.

[0082] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, it should be understood by those skilled in the art that various changes may be made to the present invention in form and details without departing from the spirit and scope of the present invention as defined by the appended claims, all of which are within the scope of protection of the present invention.

Claims

1. A gel time measuring instrument based on light scattering effect, characterized in that: It includes a laser light source, a light cutter, a first condensing lens, a second condensing lens, a sample carrier, a photoreceptor and a controller; The laser light source is used to generate incident light; The optical chopper is used to convert the incident light into sample light and reference light that are alternately and in different directions; The reference light is projected into the photoreceptor through a first condenser lens; The sample carrier is provided with at least one socket for placing a sample tube; the sample light is projected onto the sol in a sample tube loaded in the sample carrier and forms scattered light; The second condenser lens is fixed on a route that forms a certain angle with the sample light, and the scattered light is projected into the photoreceptor through the second condenser lens; The photosensitive device is connected to a host computer; The controller is connected to the laser light source and a host computer.

2. The gel time measuring instrument based on light scattering effect as claimed in claim 1, characterized in that: The incident light is pulsed laser.

3. The gel time measuring instrument based on light scattering effect as claimed in claim 1, characterized in that: The light cutter is a rotating fan-shaped mirror, which includes four fan-shaped parts: a reflector, a transmission mirror and two backgrounds, wherein the backgrounds are neither transmitting nor reflecting; the reflector and the transmission mirror are spaced apart by the backgrounds.

4. The gel time measuring instrument based on light scattering effect as claimed in claim 3, characterized in that: The rotating sector mirror is divided into four sector-shaped parts with equal areas.

5. The gel time measuring instrument based on light scattering effect as claimed in claim 1, characterized in that: The sample carrier is a turntable, and the sockets are distributed on the turntable in a circular array; a certain position of the sample carrier on the sample light path is a test position, and the sample tube is switched to the test position of the sample carrier by rotating the sample carrier.

6. The gel time measuring instrument based on light scattering effect as claimed in claim 1, characterized in that: The first condenser lens is fixed in the direction of the reference light, and the second condenser lens is fixed on a route that is 45 degrees to the sample light.

7. The gel time measuring instrument based on light scattering effect as claimed in claim 1, characterized in that: The laser light source is a pulse light source, and the incident light generated is blue light with a wavelength of 445nm and a power of 5-50mW; or green light with a wavelength of 532nm and a power of 5-50mW.

8. The gel time measuring instrument based on light scattering effect as claimed in claim 1, characterized in that: The photosensor is a photomultiplier tube.

9. A method for measuring gelation time based on light scattering effect, characterized in that: The use of the gel time measuring instrument based on light scattering effect as described in any one of claims 1 to 8 comprises the following steps: Run the test software on the host computer to set the laser pulse cycle, the constant light time of each laser pulse cycle, the signal ratio threshold and the change rate threshold; Control the laser light source to emit pulsed laser according to a set period; Receive data from the photosensitive sensor, record the average intensity of the scattered light and the average intensity of the reference light in each cycle; calculate the signal ratio of each cycle, and judge whether the gel is complete according to the gel time judgment standard. If so, stop the test and record the time of the previous cycle as the gel time. If not, continue the test until the gel is complete or the condition for forcibly ending the test is triggered, and display the test results on the terminal; the signal ratio is: the ratio of the average intensity of the scattered light in each laser pulse cycle to the average intensity of the reference light; the gel time judgment standard is: the signal ratio exceeds the signal ratio threshold, and the rate of change of the signal ratio is within the rate of change threshold; the condition for forcibly ending the test is: the test duration exceeds the maximum test time but the signal ratio is still less than the signal ratio threshold.

10. The method for measuring gel time according to claim 9, characterized in that: The method also includes a sample carrier control step: controlling the rotation speed of the turntable of the sample carrier so that the laser light source is always on when any sample tube passes through the test position.

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