High-resolution Zeta potential distribution detection device and detection method thereof
The electrophoretic light scattering signal is processed through a high-resolution Zeta potential distribution detection device and a fast orthogonal search algorithm (FOS), which solves the problem of insufficient resolution and accuracy in the prior art, and realizes high-precision detection of Zeta potential distribution.
Patent Information
- Application Number
- CN202510437668.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-09
- Publication Date
- 2025-07-04
AI Technical Summary
The existing Zeta potential detection technology has the problem of low resolution and low accuracy, especially in the Fourier transform, which leads to large errors in the calculation results.
A high-resolution Zeta potential distribution detection device is adopted, including a laser, spectrometer, lens, sample cell, electrode, beam combiner, piezoelectric ceramic reflector lens assembly, reception optical path optical assembly, optical fiber, APD detector and data acquisition card, combined with the fast orthogonal search algorithm (FOS) to process the electrophoretic light scattering signal, and the Zeta potential distribution is calculated through the autocorrelation curve and the Henry equation.
High-resolution detection of Zeta potential distribution is realized, detection accuracy is improved, spectrum leakage and peak offset are eliminated, resolution is improved by two orders of magnitude, and spectral peak positioning accuracy is better than traditional methods.
Smart Images
Figure CN120253595A_ABST
Abstract
Description
Technical Field
[0001] This invention patent relates to the technical field of detection devices for the Zeta potential of suspension systems, and specifically to a detection device for high-resolution Zeta potential distribution and its detection method. Background Art
[0002] The detection of the Zeta potential of particle suspensions has numerous applications. It can evaluate the stability of particle suspension systems. By measuring the potential formed by the surface charges of particles, it can judge the sign of particle charge and the magnitude of electrostatic repulsion between particles. A higher absolute value of the Zeta potential means good particle dispersion and a stable suspension system, while conversely, it is prone to aggregation and sedimentation. In the field of material preparation, it helps to optimize formulations. For example, in coatings, the dosage of dispersants can be adjusted according to the Zeta potential to ensure uniform dispersion of pigments; in biomedicine, it can assist in the design of drug carriers to ensure stable delivery of drugs in the body; in chemical production, it can guide process control; in sewage treatment, the Zeta potential can be used to select appropriate flocculants and dosing amounts to improve treatment efficiency.
[0003] There are various techniques for detecting the Zeta potential, including acoustic methods and optical methods, etc. Among them, the Zeta potential analyzer based on the electrophoresis light scattering technique (ELS) is one of the most widely used instrument devices in the market, and its detection results include the average Zeta potential and Zeta potential distribution of the suspension system.
[0004] The Zeta potential distribution reflects the uniformity of particle charging. The classical ELS technique performs correlation calculations on the original beat frequency signal through a correlator, obtains the spectral distribution through the Fourier transform of the correlation curve, and then obtains the frequency change Δf of the scattering signal and the electrophoretic movement speed of the particles through Lorentz fitting, and finally obtains the Zeta potential distribution information of the particles through the Henry equation. The Fourier transform is the most commonly used method in spectral calculations. When calculating the spectrum of a signal S with a calculation length L and a sampling interval ΔT, the frequency domain resolution is 1 / (L×ΔT). In the process of calculating the Zeta potential distribution through the electrophoresis light scattering signal, the calculation results are highly dependent on the spectral resolution, and the Fourier transform is difficult to meet the requirements of high-precision measurement. At the same time, assume that the signal S contains M cosine components: , where, , are the frequencies and phases of each harmonic component, and the frequencies between each harmonic do not necessarily satisfy an integer multiple relationship, so it is impossible to ensure that the finite-length signal S can contain integer multiple period samplings of all components, resulting in inevitable spectral leakage, which will also affect the resolution of the calculation results. Therefore, all spectral refinement methods based on the Fourier transform have their inherent defects. Summary of the Invention
[0005] Aiming at the deficiencies in the prior art such as low detection accuracy and low resolution of Zeta potential, the problem to be solved by the present invention is to provide a detection device and a detection method for high-resolution Zeta potential distribution.
[0006] The object of the present invention is to provide a detection device and a detection method for high-resolution Zeta potential distribution. The specific scheme is as follows: A device for high-resolution Zeta potential distribution includes a laser, a beam splitter, an attenuation sheet, a lens, a sample cell, electrodes, a beam combiner, a piezoelectric ceramic reflector lens assembly, a reflector lens, a receiving optical path optical assembly, an optical fiber, an APD detector, a digital acquisition card, and an optical trap; The beam splitter, the attenuation sheet, the lens, the sample cell, and the optical trap are sequentially arranged at the rear end of the laser, and all are arranged on one axis; The receiving optical path optical assembly consists of an optical fiber head and an optical fiber clamp; the optical fiber head is fixed by the optical fiber clamp, and the optical fiber penetrates into the optical fiber head; The laser beam emitted by the laser is split into an incident light and a reference light by the beam splitter; The incident light irradiates the sample in the sample cell through the lens, and after penetrating the sample, it enters the optical trap; The two ends of the sample cell are provided with electrodes, and the sample is immersed in the electrodes in the sample cell, and an electric field is applied to the sample through the electrodes; The incident light irradiates the sample, a voltage is applied across the electrodes to form an electric field, and the charged particles suspended in the sample perform directional electrophoresis movement under the action of the electric field force. The scattered light generated by the laser beam emitted by the laser irradiating the sample is frequency-shifted due to the electrophoresis movement of the particles; The reference light passes through the piezoelectric ceramic reflector lens assembly, and after the optical path is adjusted by the reflector mirror driven by the piezoelectric ceramic PZT, it is reflected by the reflector lens and forms a beat frequency signal with the scattered light emitted by the sample in the 12° direction through the beam combiner; The beat frequency signal enters the receiving optical path optical assembly, is conducted through the optical fiber, and then enters the APD detector; The beat frequency signal is detected by the APD detector; The signal output by the APD detector is transmitted to the PC by the data acquisition card.
[0007] For the detection device for high-resolution Zeta potential distribution, the preferred scheme is that the piezoelectric ceramic reflector lens assembly consists of a piezoelectric ceramic PZT and a reflector mirror; the optical path of the reference light is dynamically adjusted by the reflector mirror driven by the piezoelectric ceramic PZT to ensure the coherence with the scattered light.
[0008] A detection method for a detection device for high-resolution Zeta potential distribution includes the following test steps: Step 1: Turn on the device and power it on. Step 2: Set the test voltage and test time through the software in the PC. Step 3: Load the sample into the sample cell, place the sample cell into the test device, and start the test. Step 4: Apply a voltage to the sample through the electrode, and the charged particles in the sample perform directional electrophoresis movement under the action of the electric field force. Step 5: While applying a voltage to the electrode, collect the beat frequency signal formed by the scattered light and reference light of the sample, convert the beat frequency signal into an electrical signal through the APD detector, and transmit the electrical signal to the PC through the data acquisition card. Step 6: After reaching the set test time, stop applying the voltage and stop collecting the beat frequency signal. Step 7: Obtain the autocorrelation curve by calculating the electrophoretic light scattering signal obtained by the device, and then process the autocorrelation curve through the fast orthogonal search algorithm to analyze and obtain the harmonic component combination [(Δf1, I1),…,(Δf n , I n )], where I n is the corresponding frequency, and Δf n is the component intensity at that frequency. Obtain the electrophoretic mobility μ at each frequency through the formula , where n is the refractive index of the dispersion liquid, 𝝀 is the laser wavelength, θ is the angle between the scattered light and the incident light, and E is the electric field strength. Substitute the electrophoretic mobility of the system into the Herry equation: Calculate the corresponding Zeta potential ζ information; where f(κα) is the Henry function, κ is the reciprocal of the Debye radius, α represents the particle size, ε r is the relative dielectric constant, ε0 is the vacuum dielectric constant, and κα represents the ratio of the double-layer thickness to the particle radius. In this way, a harmonic component array corresponding to the Zeta potential that meets the requirement of the minimum fitting variance is obtained. Taking the Zeta potential in this array as the abscissa and the harmonic component intensity as the ordinate, a Zeta potential distribution diagram is obtained. The fast orthogonal search algorithm - Fast Orthogonal Search, abbreviated as the FOS algorithm.
[0009] The detection method of the detection device for high-resolution Zeta potential distribution preferably includes, in step seven, screening out the harmonic components corresponding to the minimum fitting variance requirement through one iteration by the FOS algorithm to generate a simplified harmonic component expression; the harmonic frequency resolution is not limited by the sampling duration and can distinguish two frequency components with an interval of the highest resolution of the Fourier transform.
[0010] The detection method of the detection device for high-resolution Zeta potential distribution preferably includes, in step seven, in the calculation of the electrophoretic mobility μ, the angle θ between the scattered light and the incident light is fixed at 12°, and the electric field strength E is determined by the voltage applied by the electrode and the size of the sample cell. In the Henry equation, the function f(κα) is related to the measured values of the particle size α and the reciprocal of the Debye radius κ. The set value of f(κα) for the aqueous phase system sample is 1.5, and the set value of f(κα) for the organic phase system is 1.0.
[0011] The detection method of the detection device for high-resolution Zeta potential distribution preferably includes, in step two, setting the test voltage in the range of 0V to 150V according to the conductivity of the sample; when the conductivity is less than or equal to 5mS / cm, the set voltage value is 150V; when the conductivity is 5mS / cm to 30mS / cm, the set voltage value is 100V; when the conductivity is greater than or equal to 30mS / cm, the set voltage value is 10V; the test time is 0.5 seconds. Beneficial effects
[0012] The technical solution of the present invention uses the FOS fast orthogonal search algorithm to process the autocorrelation curve obtained by electrophoretic light scattering, which can achieve a higher frequency resolution estimation of the signal frequency, phase, and amplitude. The FOS algorithm selects the appropriate harmonic component function only through one iteration and can greatly reduce the mean square error between the estimator and the input signal. Brief description of the drawings
[0013] Figure 1 It is a schematic optical path structure diagram of the present invention; Figure 2 It is the drift-removed autocorrelation curve of the unimodal sample obtained by the device of the present invention; Figure 3 It is the spectral distribution of the unimodal Zeta potential result obtained by Fourier transform; Figure 4 It is the spectral distribution of the unimodal Zeta potential result obtained by the FOS algorithm; Figure 5 It is the drift-removed autocorrelation curve of the unimodal Zeta potential result reconstructed from the result of the FOS algorithm; Figure 6 It isFigure 3 Zeta potential distribution curve corresponding to the spectrum; Figure 7 is Figure 4 Zeta potential distribution curve corresponding to the spectrum; Figure 8 is the detrended autocorrelation curve of the bimodal Zeta potential result obtained by the device of the present invention; Figure 9 is the spectrum distribution of the bimodal Zeta potential result obtained by Fourier transform; Figure 10 is the spectrum distribution of the bimodal Zeta potential result obtained by the FOS algorithm; Figure 11 is the detrended autocorrelation curve of the bimodal Zeta potential result reconstructed from the FOS algorithm result; Figure 12 is Figure 9 Zeta potential distribution curve corresponding to the spectrum; Figure 13 is Figure 10 Zeta potential distribution curve corresponding to the spectrum.
[0014] In the figure, 1. Laser, 2. Beam splitter, 3. Attenuator, 4. Lens, 5. Sample cell, 6. Electrode, 7. Beam combiner, 8. Incident light, 9. Piezoelectric ceramic mirror assembly, 10. Reference light, 11. Reflecting mirror, 12. Receiving optical path optical assembly, 13. Optical fiber, 14. APD detector, 15. Data acquisition card, 16. Scattered light, 17. Beat signal, 18. Optical trap, 19. Sample, 20. PC. Detailed implementation mode
[0015] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.
[0016] Embodiment 1
[0017] As Figures 1 - 13 shown, a detection device for high-resolution Zeta potential distribution includes a laser 1, a beam splitter 2, an attenuator 3, a lens 4, a sample cell 5, an electrode 6, a beam combiner 7, a piezoelectric ceramic mirror assembly 9, a reflecting mirror 11, a receiving optical path optical assembly 12, an optical fiber 13, an APD detector 14, a digital acquisition card 15 and an optical trap 18; A beam splitter 2, an attenuation sheet 3, a lens 4, a sample cell 5, and an optical trap 18 are sequentially arranged at the rear end of the laser 1, and all are arranged on the same axis; The receiving optical path optical component 12 is composed of an optical fiber head and an optical fiber clamp; the optical fiber head is fixed by the optical fiber clamp, and the optical fiber 13 penetrates into the optical fiber head; The laser light emitted by the laser 1 is split into incident light 8 and reference light 10 by the beam splitter 2; The incident light 8 irradiates the sample 19 in the sample cell 5 through the lens 4, and after penetrating the sample 19, it enters the optical trap 18; Electrodes 6 are provided at both ends of the sample cell 5, and the sample 19 is immersed in the electrodes 6 in the sample cell 5, and an electric field is applied to the sample 19 through the electrodes 6; The incident light 8 irradiates the sample 19, a voltage is applied across the electrodes 6 to form an electric field, and the charged particles suspended in the sample 19 perform directional electrophoresis movement under the action of the electric field force. The scattered light 16 generated by the laser light emitted by the laser 1 irradiating the sample 19 is frequency-shifted due to the electrophoresis movement of the particles; The reference light 10 passes through the piezoelectric ceramic reflecting mirror assembly 9, and after the optical path is adjusted by the reflecting mirror driven by the piezoelectric ceramic PZT, and then reflected by the reflecting mirror 11, it forms a beat signal 17 with the scattered light 16 emitted by the sample 19 in the 12° direction through the beam combiner 7; The beat signal 17 enters the receiving optical path optical component 12, is conducted through the optical fiber 13, and then enters the APD detector 14; The beat signal 17 is detected by the APD detector 14; The output signal of the APD detector 14 is transmitted to the PC 20 by the data acquisition card 15.
[0018] The piezoelectric ceramic reflecting mirror assembly 9 is composed of a piezoelectric ceramic PZT drive and a reflecting mirror; the optical path of the reference light 10 is dynamically adjusted by the piezoelectric ceramic PZT to drive the reflecting mirror to ensure the coherence with the scattered light 16.
[0019] A detection method for a detection device of a high-resolution Zeta potential distribution includes the following test steps: Step 1: Turn on the device and power it on; Step 2: Set the test voltage and test time through the software in the PC 20; the set test voltage is in the range of 0V to 150V, and is set according to the conductivity of the sample; when the conductivity is less than or equal to 5mS / cm, the set voltage value is 150V; when the conductivity is 5mS / cm to 30mS / cm, the set voltage value is 100V; when the conductivity is greater than or equal to 30mS / cm, the set voltage value is 10V; the test time is 0.5 seconds; Step 3: Load the sample 19 into the sample cell 5, place the sample cell 5 into the testing device, and start the test; Step 4: Apply a voltage to the sample 19 through the electrode 6, and the charged particles in the sample 19 perform directional electrophoresis movement under the action of the electric field force; Step 5: While applying a voltage to the electrode 6, collect the beat frequency signal 17 formed by the sample scattered light 16 and the reference light 10, convert the beat frequency signal 17 into an electrical signal through the APD detector 14, and transmit the electrical signal to the PC 20 through the data acquisition card 15; Step 6: After reaching the set test time, stop applying the voltage and stop collecting the beat frequency signal 17; Step 7: As Figures 2 - 5 and Figures 8 - 11 shown, test a single-peak Zeta sample and a double-peak Zeta potential sample respectively. Perform autocorrelation operation on the electrophoretic light scattering signal obtained by the device to obtain the correlation curve, and then obtain the detrended autocorrelation curve after detrending processing. Process the correlation curve through Fourier transform and through the fast orthogonal search algorithm to obtain the spectrum. Among them, the fast orthogonal search algorithm analyzes and obtains a set of optimal frequency combination harmonic components [(Δf1, I1),…,(Δf n , I n )], where I n is the component intensity corresponding to the frequency Δf n ; Reconstruct the autocorrelation curve with the component intensity obtained by using the fast orthogonal search algorithm, and its characteristics are the same as the original detrended autocorrelation curve; As Figures 6 - 7 and Figures 12 - 13 shown, through the formula obtain the electrophoretic mobility μ at each frequency, where n is the refractive index of the dispersion liquid, 𝝀 is the laser wavelength, θ is the included angle between the scattered light and the incident light, and E is the electric field strength; Substitute the electrophoretic mobility of the system into the Herry equation: Calculate the corresponding Zeta potential ζ information; where f(κα) is the Henry function, κ is the reciprocal of the Debye radius, α represents the particle size, ε r is the relative dielectric constant, ε0 is the vacuum dielectric constant, and κα represents the ratio of the double-layer thickness to the particle radius.
[0020] The f(κα) function in the Herry equation is related to the measured values of the particle size α and the reciprocal of the Debye radius κ. The set value of f(κα) for the aqueous phase system sample is 1.5, and the set value of f(κα) for the organic phase system is 1.0.
[0021] A set of harmonic component arrays composed of optimal Zeta potentials can be obtained through the fast orthogonal search algorithm, and the detection accuracy of its Zeta potential distribution is much higher than that of the Zeta potential distribution obtained by processing signals through Fourier transform; Taking the Zeta potential in this array as the abscissa and the harmonic component intensity as the ordinate, a Zeta potential distribution diagram is obtained; Fast Orthogonal Search algorithm - abbreviated as FOS algorithm.
[0022] In the present invention, the FOS algorithm screens out the optimal harmonic components to obtain a simplified harmonic component expression; the obtained harmonic frequency is not limited by the sampling duration, and two frequency components with an interval of the highest resolution of Fourier transform can be clearly distinguished.
[0023] In the present invention, the resolution of the Zeta potential distribution obtained through the FOS algorithm is improved by two orders of magnitude compared with the traditional fast Fourier transform (FFT), and the spectral peak positioning accuracy is better than one order of magnitude; the present invention eliminates the spectral leakage caused by non-integer multiple truncation of the signal through the FOS algorithm, avoiding spectral broadening and peak shift.
Claims
1. A detection device for high-resolution Zeta potential distribution, characterized in that: It includes a laser (1), a beam splitter (2), an attenuation sheet (3), a lens (4), a sample cell (5), electrodes (6), a beam combiner (7), a piezoelectric ceramic mirror assembly (9), a mirror (11), a receiving optical path optical assembly (12), an optical fiber (13), an APD detector (14), a digital acquisition card (15), and an optical trap (18); The beam splitter (2), the attenuation sheet (3), the lens (4), the sample cell (5), and the optical trap (18) are sequentially arranged at the rear end of the laser (1), and all are arranged on the same axis; The receiving optical path optical assembly (12) consists of an optical fiber head and an optical fiber clamp; the optical fiber head is fixed by the optical fiber clamp, and the optical fiber (13) penetrates into the optical fiber head; The laser beam emitted by the laser (1) is split into an incident light (8) and a reference light (10) by the beam splitter (2); The incident light (8) irradiates the sample (19) in the sample cell (5) through the lens (4), and after penetrating the sample (19), it enters the optical trap (18); Electrodes (6) are provided at both ends of the sample cell (5), and the sample (19) is immersed in the electrodes (6) in the sample cell (5), and an electric field is applied to the sample (19) through the electrodes (6); The incident light (8) irradiates the sample (19), a voltage is applied across the electrodes (6) to form an electric field, and the charged particles suspended in the sample (19) perform directional electrophoresis movement under the action of the electric field force. The scattered light (16) generated by the laser beam emitted by the laser (1) irradiating the sample (19) is frequency-shifted due to the electrophoresis movement of the particles; The reference light (10) passes through the piezoelectric ceramic mirror assembly (9), and after the optical path is adjusted by the mirror driven by the piezoelectric ceramic PZT, and then reflected by the mirror (11), it forms a beat signal (17) with the scattered light (16) emitted by the sample (19) in the 12° direction through the beam combiner (7); The beat signal (17) enters the receiving optical path optical assembly (12), is conducted through the optical fiber (13), and then enters the APD detector (14); The beat signal (17) is detected by the APD detector (14); The signal output by the APD detector (14) is transmitted to the PC (20) by the data acquisition card (15).
2. The detection device for high-resolution Zeta potential distribution according to claim 1, characterized in that: The piezoelectric ceramic mirror assembly (9) consists of a piezoelectric ceramic PZT and a mirror; the optical path of the reference light (10) is dynamically adjusted by driving the mirror with the piezoelectric ceramic PZT to ensure the coherence with the scattered light (16).
3. The detection method of a detection device for high-resolution Zeta potential distribution according to claim 2, characterized in that, It includes the following test steps: Step 1: Turn on the device and power it on; Step 2: Set the test voltage and test time through the software in the PC (20); Step 3: Load the sample (19) into the sample cell (5), place the sample cell (5) into the test device, and start the test; Step 4: Apply a voltage to the sample (19) through the electrodes (6), and the charged particles in the sample (19) perform directional electrophoresis movement under the action of the electric field force; Step Five: While applying a voltage to the electrode (6), collect the beat signal (17) formed by the scattered light (16) and the reference light (10) of the sample. Convert the beat signal (17) into an electrical signal through the APD detector (14), and transmit the electrical signal to the PC (20) through the data acquisition card (15); Step Six: After reaching the set test time, stop applying the voltage and stop collecting the beat signal (17); Step 7: Calculate the autocorrelation curve from the electrophoretic light scattering optical signals obtained by the device, and then process the autocorrelation curve through the Fast Orthogonal Search algorithm to analytically obtain the harmonic component combinations [(Δf1, I1),…,(Δf n , I n )], where I n is the corresponding frequency and Δf n is the component intensity at that frequency; By the formula Obtain the electrophoretic mobility μ at each frequency, where n is the refractive index of the dispersion, 𝝀 is the laser wavelength, θ is the angle between the scattered light and the incident light, and E is the electric field strength; Substitute the electrophoretic mobility of the system into the Henry equation: Calculate the corresponding Zeta potential ζ information; where f(κα) is the Henry function, κ is the reciprocal of the Debye radius, α represents the particle size, ε r is the relative permittivity, ε0 is the permittivity of vacuum, and κα represents the ratio of the double-layer thickness to the particle radius; In this way, an array of harmonic components composed of a set of optimal Zeta potentials is obtained; Using the Zeta potential in this array as the abscissa and the harmonic component intensity as the ordinate, obtain the Zeta potential distribution map; The Fast Orthogonal Search algorithm - abbreviated as the FOS algorithm.
4. The detection method of a detection device for high-resolution Zeta potential distribution according to claim 3, characterized in that: In Step Seven, through the FOS algorithm, screen out the harmonic components corresponding to the minimum fitting variance requirement through one iteration, and generate a simplified harmonic component expression; the harmonic frequency resolution is not limited by the sampling duration, and can distinguish two frequency components with an interval of the highest resolution of the Fourier transform.
5. The detection method of a detection device for high-resolution Zeta potential distribution according to claim 3, characterized in that: In Step Seven, in the calculation of the electrophoretic mobility μ, the angle θ between the scattered light and the incident light is fixed at 12°, and the electric field strength E is determined by the voltage applied to the electrode (6) and the size of the sample cell (5); In the Henry equation, the f(κα) function is related to the measured values of the particle size α and the reciprocal of the Debye radius κ. The set value of f(κα) for the aqueous phase system sample is 1.5, and the set value of f(κα) for the organic phase system is 1.
0.
6. The detection method of a detection device for detecting high-resolution Zeta potential distribution according to claim 3, characterized in that: In Step Two, set the test voltage within the range of 0V to 150V, which is set according to the conductivity of the sample; when the conductivity is less than or equal to 5mS / cm, set the voltage value to 150V; when the conductivity is 5mS / cm to 30mS / cm, set the voltage value to 100V; when the conductivity is greater than or equal to 30mS / cm, set the voltage value to 10V; the test time is 0.5 seconds.