Zeta potential measurement system based on Y-type coupling optical fiber

Abstract

The invention discloses a Zeta potential measurement system based on a Y-type coupling optical fiber. In the system, an incident light source generates incident light; the incident light passes through the first beam splitter, part of light is split as reference light, the other part of light is converged at the center of the sample cell, and a nanoparticle sample solution in the sample cell is irradiated by the incident light to generate scattered light; reference light and scattered light are respectively received through two receiving ends of the Y-shaped optical fiber coupler, and the reference light and the scattered light generate coherent optical signals in the Y-shaped optical fiber coupler. The Y-shaped optical fiber coupler is used for receiving and transmitting optical signals, interference of stray light is reduced, drifting caused by movement of atmosphere in the environment or a measuring device and the like is weakened, then measurement errors of Zeta potential information of the nano-particles are reduced, and the Zeta potential information of the weak scattering nano-particles can be measured more accurately.

Description

Technical Field

[0001] The invention relates to the technical field of nanoparticle measurement, and in particular to a zeta potential measurement system based on Y-type coupled optical fiber. Background Art

[0002] Nanomaterials are widely used in chemistry, environment, medicine, pharmaceuticals and materials due to their unique physical and chemical properties. Nanoparticles are an important component of nanomaterials, among which Zeta potential is an important characterization property of nanoparticles. The Zeta potential of nanoparticles is an important indicator to characterize the stability of colloidal particle systems. By measuring the Zeta potential of nanoparticles in colloidal solutions, we can study the surface charge distribution and surface potential of these particles, and predict and control the stability of colloidal suspensions. The higher the Zeta potential, the better the stability of colloidal particles.

[0003] The traditional Zeta potential measurement system directly uses a photodetector to receive reference light and scattered light, and generates coherent light signals in the photodetector. The traditional Zeta potential measurement system is usually tested in an open environment, and its defects are: natural light, reference light and scattered light are mixed together and enter the photodetector; the object to be measured is far away from the photodetector, and the reference light and scattered light are easily drifted on the receiving surface due to the atmosphere in the environment or the movement of the measuring device, resulting in the inability to effectively generate coherent light. These factors undoubtedly increase the difficulty of detection and reduce the signal-to-noise ratio (All-fiber optical path electrophoresis light scattering Zeta potential measurement device and measurement method (CN109030320A)). Summary of the invention

[0004] The purpose of the present invention is to provide a Zeta potential measurement system based on a Y-type coupled optical fiber to solve the technical problem that the Zeta potential of nanoparticles cannot be accurately measured at present. The reference light and the scattered light are received by two receiving ends of the Y-type optical fiber coupler respectively, and the reference light and the scattered light generate coherent optical signals in the Y-type optical fiber coupler. The Y-type optical fiber coupler is used to receive and transmit optical signals to reduce the interference of stray light, reduce the drift caused by the atmosphere in the environment or the movement of the measuring device, and thus reduce the measurement error of the Zeta potential information of the nanoparticles, so that the Zeta potential information of weakly scattered nanoparticles can be measured more accurately.

[0005] The purpose of the present invention is achieved by at least one of the following technical solutions.

[0006] A zeta potential measurement system based on a Y-type coupled optical fiber, comprising an incident light source, a first beam splitter, a first convex lens, a sample cell, a second convex lens, a second beam splitter, a reflector, a PZT, a Y-type optical fiber coupler, a photodetector, and a signal processor;

[0007] The incident light source is used to generate incident light; the incident light passes through the first beam splitter, and part of the light is separated as reference light, and the other part passes through the first convex lens and converges at the center of the sample pool; the sample pool is used to hold the nanoparticle sample solution and is arranged on the optical path of the incident light, and the nanoparticle sample solution in the sample pool generates scattered light after being irradiated by the incident light; the reference light is transmitted through the second beam splitter and enters the reflector; the reflector is used to reflect the reference light, and the reference light reflected by the reflector is reflected by the second beam splitter and enters the Y-type fiber coupler; the PZT is used to drive the reflector to generate displacement;

[0008] The second convex lens is used to receive scattered light and converge it into the Y-type fiber coupler; the Y-type fiber coupler is used to receive reference light and scattered light, and couple the reference light and scattered light to obtain a coherent light signal; the photodetector is connected to the Y-type fiber coupler, and the photodetector receives the coherent light signal and converts it into an electrical signal; the signal processor receives the electrical signal and fits it to obtain a light intensity autocorrelation function, and calculates the Zeta potential information of the output nanoparticles according to the light intensity autocorrelation function.

[0009] Furthermore, the Y-type fiber coupler is a 1×2 single-mode visible light fused fiber coupler with a central wavelength of 632nm and a splitting ratio of 50:50. The Y-type fiber coupler is used to receive reference light and scattered light, and couple the reference light and scattered light to obtain a coherent optical signal.

[0010] Furthermore, the first beam splitter is only used for energy splitting without considering the polarization state, and the splitting ratio is 50:50.

[0011] Furthermore, the sample pool is a quartz glass cuvette with a refractive index of 1.43, which is used to hold the sample solution.

[0012] Further, the second convex lens is disposed between the sample pool and the Y-type optical fiber coupler, and is used to converge the scattered light into the Y-type optical fiber coupler;

[0013] The first convex lens is disposed between the first beam splitter and the sample cell, and is used to converge the incident light passing through the first beam splitter into the sample cell.

[0014] Furthermore, the PZT is a piezoelectric ceramic actuator, which is used to change the optical path of the reference light, thereby achieving a set frequency shift between the reference light and the scattered light.

[0015] Furthermore, the reflector is fixed to the PZT and is used to change the propagation direction of the reference light.

[0016] Furthermore, the photoelectric detector adopts a photon counting-level photomultiplier tube, which is used to receive the coherent optical signal transmitted by the Y-type optical fiber coupler and convert the optical signal into an electrical signal.

[0017] Furthermore, the signal processor receives the electrical signal and obtains a light intensity autocorrelation function by fitting, and calculates and outputs zeta information of the nanoparticles according to the light intensity autocorrelation function.

[0018] Furthermore, a cutoff is provided after the sample cell in the optical path of the incident light;

[0019] The first beam splitter, the first convex lens, the sample cell and the beam cutoff are arranged on the optical path of the incident light in the order of incidence. The beam cutoff is used to receive the transmitted light beam generated after the incident light passes through the sample cell, so as to reduce the influence of the transmitted light beam on the scattering result.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] The present invention provides a zeta potential measurement system based on a Y-type coupling optical fiber. The Y-type coupling optical fiber is combined to form a relatively closed optical detection environment, which can reduce the influence of external stray light such as natural light, effectively utilize the two receiving ends of the Y-type optical fiber coupler to receive reference light and scattered light, and generate a coherent optical signal in the Y-type optical fiber coupler, thereby reducing the measurement error of the zeta potential information of nanoparticles and being able to more accurately measure the zeta potential information of nanoparticles. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of a Zeta potential measurement system based on a Y-type coupled optical fiber in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the light intensity autocorrelation function curve obtained by measuring nanoparticles using the traditional Zeta potential measurement method in the embodiment;

[0024] Figure 3 Schematic diagram of the light intensity autocorrelation function curve obtained by measuring nanoparticles using a Zeta potential measurement system based on a Y-type coupled optical fiber in the embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following description combines specific illustrations to explain the technical solution so as to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and similar generalized embodiments made by ordinary technicians in this field without creative work are all within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices and elements referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0027] In the description of the present invention, it should be understood that the present invention uses the terms "first", "second", etc. to describe various information, but these information should not be limited to these terms, and these terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, "first" information may also be referred to as "second" information, and similarly, "second" information may also be referred to as "first" information.

[0028] Example:

[0029] A Zeta potential measurement system based on Y-type coupled optical fiber, such as Figure 1 As shown, it includes an incident light source 1, a first beam splitter 2, a first convex lens 3, a sample pool 4, a second convex lens 9, a second beam splitter 6, a reflector 7, a PZT 8, a Y-type fiber coupler 10, a photodetector 11, and a signal processor 12;

[0030] The incident light source 1 is used to generate incident light; the incident light passes through the first beam splitter 2, and a part of the light is separated as the reference light, and the other part passes through the first convex lens 3 and converges at the center of the sample pool 4; the sample pool 4 is used to hold the nanoparticle sample solution and is arranged on the optical path of the incident light, and the nanoparticle sample solution in the sample pool 4 generates scattered light after being irradiated by the incident light; the reference light is transmitted through the second beam splitter 6 and enters the reflector 7; the reflector 7 is used to reflect the reference light, and the reference light reflected by the reflector 7 is reflected by the second beam splitter 6 and enters the Y-type fiber coupler 10; the PZT 8 is used to drive the reflector 7 to generate displacement;

[0031] The second convex lens 9 is used to receive the scattered light and converge it into the Y-type fiber coupler 10; the Y-type fiber coupler 10 is used to receive the reference light and the scattered light, and couple the reference light and the scattered light to obtain a coherent light signal; the photodetector 11 receives the coherent light signal and converts it into an electrical signal; the signal processor receives the electrical signal and fits it to obtain the light intensity autocorrelation function, and calculates the Zeta potential information of the output nanoparticles according to the light intensity autocorrelation function.

[0032] In one embodiment, the incident light source 1 is a laser, and a 633nm, 25mW high-stability red laser is selected.

[0033] In one embodiment, the Y-type optical fiber coupler 10 is a 1×2 single-mode visible light fused optical fiber coupler with a central wavelength of 632 nm and a splitting ratio of 50:50.

[0034] In one embodiment, Figure 1 As shown, the Y-type fiber coupler 10 includes a first receiving end 10A and a second receiving end 10B, wherein the first receiving end 10A is arranged at the imaging position of the scattered light emitted by the second convex lens 9, and is used to receive the scattered light; the second receiving end 10B is arranged on the optical path of the reference light emitted by the second beam splitter 6, and is used to receive the reference light; the Y-type fiber coupler 10 is used to receive the reference light and the scattered light of the nanoparticles, and couple the reference light and the scattered light to obtain a coherent optical signal.

[0035] Preferably, the first beam splitter plate 2 is only used for energy splitting without considering the polarization state, and the splitting ratio is 50:50.

[0036] In one embodiment, the sample pool 4 is a quartz glass cuvette with a refractive index of 1.43, and is used to contain the sample solution.

[0037] Further, the second convex lens 9 is disposed between the sample pool 4 and the Y-type optical fiber coupler 10, and is used to converge the scattered light into the Y-type optical fiber coupler 10;

[0038] The first convex lens 3 is disposed between the first beam splitter 2 and the sample pool 4 , and is used to converge the incident light passing through the first beam splitter 2 into the sample pool 4 .

[0039] In one embodiment, the first convex lens 3 is a double convex lens with a focal length of 100 mm.

[0040] In one embodiment, the second convex lens 9 is a double convex lens with a focal length of 30 mm, the distance between the center of the sample pool 4 and the second convex lens 9 is 55 mm, and the distance between the second convex lens 9 and the Y-type optical fiber coupler 10 is 66 mm.

[0041] In one embodiment, the PZT8 is a piezoelectric ceramic actuator with a movement range of 19 μm and a resonance frequency of 30 KHZ, and is used to change the optical path of the reference light, thereby achieving a set frequency shift between the reference light and the scattered light.

[0042] Furthermore, the reflector 7 is fixed to the PZT 8 to change the propagation direction of the reference light.

[0043] Furthermore, the photodetector 11 is connected to the Y-type optical fiber coupler 10 to receive the coherent optical signal transmitted by the Y-type optical fiber coupler 10 and convert the optical signal into an electrical signal.

[0044] In one embodiment, the photodetector 11 is a photon counting level photomultiplier tube.

[0045] Furthermore, the signal processor 12 receives the electrical signal and obtains a light intensity autocorrelation function by fitting, and calculates and outputs zeta information of the nanoparticles according to the light intensity autocorrelation function.

[0046] Furthermore, a cutoff device 5 is provided after the sample pool 4 in the optical path of the incident light;

[0047] The first beam splitter 2, the first convex lens 3, the sample cell 4 and the beam cutoff 5 are arranged on the optical path of the incident light in the order of incidence. The beam cutoff 5 is used to receive the transmitted light beam generated after the incident light passes through the sample cell 4, so as to reduce the influence of the transmitted light beam on the scattering result.

[0048] In one embodiment, the working process of a zeta potential measurement system based on a Y-type coupled optical fiber is as follows:

[0049] S1: Turn on the incident light source 1, and the incident light passes through the first beam splitter 2 to separate part of the light as the reference light. The incident light is converged by the first convex lens 3 and enters the sample pool 4. The light beam transmitted through the sample pool 4 enters the beam cutoff 5. The scattered light beam of the sample pool 4 enters the first receiving end 10A of the Y-type optical fiber coupler 10 through the second convex lens 9;

[0050] S2: The reference beam split by the first beam splitter 2 is incident on the reflector 7 via the second beam splitter 6, and the reflector 7 reflects the reference beam;

[0051] S3: Turn on the power of PZT8, PZT8 drives the reflector 7 to perform micro displacement, change the optical path of the reference light, and the light beam reflected by the reflector 7 is reflected by the second beam splitter 6 and enters the second receiving end 10B of the Y-type optical fiber coupler 10;

[0052] S5: Turn on the photodetector 11, and the Y-type fiber coupler 10 transmits the light intensity signal to the photodetector 11 and converts it into an electrical signal;

[0053] S6: Turn on the signal processor 12 to receive and process the electrical signal transmitted by the photodetector 11; obtain the light intensity autocorrelation function according to the electrical signal, and calculate the zeta information of the output nanoparticles according to the light intensity autocorrelation function.

[0054] In summary, the embodiment of the present invention provides a Zeta potential measurement system based on a Y-type coupled optical fiber, which effectively utilizes the two receiving ends of the Y-type optical fiber coupler to receive reference light and scattered light through an incident light source, a first beam splitter, a first lens, a sample cell, a second lens, a second beam splitter, a reflector, a PZT, a Y-type optical fiber coupler, a photodetector, and a signal processor, and generates a coherent light signal in the Y-type optical fiber coupler, thereby reducing the measurement error of the Zeta potential information of the nanoparticles and being able to more accurately measure the Zeta potential information of the nanoparticles.

[0055] In one embodiment, the present invention uses a Y-type coupled optical fiber based Zeta potential measurement system and a traditional Zeta potential measurement system to measure the zeta potential information of common nanoparticles, as follows:

[0056] In the measurement experiment, a standard nanoparticle sample solution with a particle size of 220 nm was used, and its zeta potential nominal value was -42mV±4.2mV. Figure 2 This is the nanoparticle light intensity autocorrelation function curve obtained by the traditional Zeta potential measurement system. Figure 3 The graph is a nanoparticle light intensity autocorrelation function curve obtained by the Zeta potential measurement system based on the Y-type coupled optical fiber of the present invention. Figure 2 In the experiment, the scattered light from particles is disturbed by stray light. The experimental curve contains the changing trends of periodic oscillation curve and exponential decay curve. The baseline is not a straight line, but a line accompanied by low-frequency fluctuations. Figure 3 In the curve, the periodic oscillation signal is basically a line fluctuation symmetrically around the baseline low-frequency fluctuation, which can effectively avoid the interference of stray light and present a light intensity autocorrelation function with good quality. In addition, the Zeta potential information obtained by the traditional Zeta potential measurement system is -33.6mV, with an error of 8.4mV; the Zeta potential information of the Zeta potential measurement system based on the Y-type coupled optical fiber of the present invention is -41.0mV, with an error of 1.0nm. It can be seen that the Zeta potential measurement system based on the Y-type coupled optical fiber of the present invention can more accurately measure the Zeta potential information of nanoparticles.

[0057] The preferred embodiments of the present application disclosed above are only used to help understand the present invention and its core ideas. For those skilled in the art, according to the ideas of the present invention, there will be changes in specific application scenarios and implementation operations, and this specification should not be interpreted as limiting the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A Zeta potential measurement system based on Y-type coupled optical fiber, characterized in that: It comprises an incident light source (1), a first beam splitter (2), a first convex lens (3), a sample pool (4), a second convex lens (9), a second beam splitter (6), a reflector (7), a PZT (8), a Y-type optical fiber coupler (10), a photodetector (11), and a signal processor (12); The incident light source (1) is used to generate incident light; the incident light passes through a first beam splitter (2), a portion of the light is separated as reference light, and the other portion passes through a first convex lens (3) and converges at the center of a sample pool (4); the sample pool (4) is used to contain a nanoparticle sample solution and is arranged on the optical path of the incident light, and the nanoparticle sample solution in the sample pool (4) generates scattered light after being irradiated by the incident light; the reference light passes through a second beam splitter (6) and is transmitted into a reflector (7); the reflector (7) is used to reflect the reference light, and the reference light reflected by the reflector (7) is reflected by the second beam splitter (6) and enters the Y-type optical fiber coupler (10); the PZT (8) is used to drive the reflector (7) to generate displacement; The second convex lens (9) is used to receive scattered light and converge it into the Y-type optical fiber coupler (10); the Y-type optical fiber coupler (10) is used to receive reference light and scattered light, and couple the reference light and scattered light to obtain a coherent light signal; the photodetector (11) is connected to the Y-type optical fiber coupler (10), and the photodetector (11) receives the coherent light signal and converts it into an electrical signal; the signal processor receives the electrical signal and fits it to obtain a light intensity autocorrelation function, and calculates the Zeta potential information of the output nanoparticles according to the light intensity autocorrelation function.

2. The Zeta potential measurement system based on Y-type coupled optical fiber according to claim 1, characterized in that: The Y-type optical fiber coupler (10) is a 1×2 single-mode visible light fused optical fiber coupler with a central wavelength of 632 nm and a splitting ratio of 50:

50. The Y-type optical fiber coupler (10) is used to receive reference light and scattered light, and couple the reference light and scattered light to obtain a coherent optical signal.

3. The zeta potential measurement system based on Y-type coupled optical fiber according to claim 1, characterized in that: The first beam splitter plate (2) is only used for energy splitting without considering the polarization state, and the splitting ratio is 50:

50.

4. The zeta potential measurement system based on Y-type coupled optical fiber according to claim 1, characterized in that: The sample pool (4) is a quartz glass cuvette with a refractive index of 1.43 and is used for containing sample solutions.

5. The Zeta potential measurement system based on Y-type coupled optical fiber according to claim 1, characterized in that: The second convex lens (9) is arranged between the sample pool (4) and the Y-shaped optical fiber coupler (10), and is used to converge the scattered light into the Y-shaped optical fiber coupler (10); The first convex lens (3) is arranged between the first beam splitter (2) and the sample pool (4), and is used to converge the incident light passing through the first beam splitter (2) into the sample pool (4).

6. The Zeta potential measurement system based on Y-type coupled optical fiber according to claim 1, characterized in that: The PZT (8) is a piezoelectric ceramic actuator, which is used to change the optical path of the reference light, thereby achieving a set frequency shift between the reference light and the scattered light.

7. The zeta potential measurement system based on Y-type coupled optical fiber according to claim 1, characterized in that: The reflector (7) is fixed to the PZT (8) and is used to change the propagation direction of the reference light.

8. The Zeta potential measurement system based on Y-type coupled optical fiber according to claim 1, characterized in that: The photoelectric detector (11) adopts a photon counting-level photomultiplier tube, which is used to receive the coherent optical signal transmitted by the Y-type optical fiber coupler (10) and convert the optical signal into an electrical signal.

9. The Zeta potential measurement system based on Y-type coupled optical fiber according to claim 1, characterized in that: The signal processor (12) receives the electrical signal and obtains a light intensity autocorrelation function by fitting, and calculates and outputs zeta information of the nanoparticles according to the light intensity autocorrelation function.

10. The Zeta potential measurement system based on Y-type coupled optical fiber according to claim 1, characterized in that: A cutoff device (5) is arranged behind the sample pool (4) on the optical path of the incident light; A first beam splitter (2), a first convex lens (3), a sample cell (4) and a beam cutoff (5) are arranged on the optical path of the incident light in the order of incidence, and the beam cutoff (5) is used to receive a transmitted light beam generated after the incident light passes through the sample cell (4), thereby reducing the influence of the transmitted light beam on the scattering result.

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