A simulation optimization method for rectangular electrode quadrupoles
By optimizing the physical and electric field parameters of the rectangular electrode quadrupole, the problem of electric field distortion in the mass spectrometer was solved, improving ion transmission efficiency and detection capability, and achieving a balance between miniaturization and high performance of the mass spectrometer.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WUYI UNIV
- Filing Date
- 2026-01-27
- Publication Date
- 2026-05-26
AI Technical Summary
In existing mass spectrometers, rectangular electrode quadrupoles are easy to manufacture but are prone to introducing electric field distortion, which leads to a decrease in ion transmission efficiency. It is difficult to achieve both the miniaturization of the mass spectrometer and efficient and stable ion transmission.
By determining the physical parameters of the rectangular electrode quadrupole, constructing a geometric model and coupling multiple physics fields, establishing a simulation optimization model, optimizing the electrode size and electric field parameters, and realizing the simulation analysis and verification of ion transport efficiency.
The ion transport capability and wide mass range detection capability of the rectangular electrode quadrupole have been improved, enabling the mass spectrometer to achieve a balance between miniaturization and high performance.
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Figure CN122088166A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the technical field of core components of mass spectrometers, and in particular to a simulation optimization method for a rectangular electrode quadrupole. Background Technology
[0002] The quadrupole mass analyzer is the core component of a mass spectrometer, and its performance directly determines the spectrometer's sensitivity, resolution, and detection range. Current mass spectrometers mostly use hyperboloid or cylindrical quadrupoles, which offer stable performance but require high manufacturing precision and have a small effective ion channel ratio, hindering miniaturization. While existing rectangular electrode quadrupoles are easy to manufacture, they are prone to introducing multipole field components, causing electric field distortion and reducing ion transmission efficiency. Therefore, it is difficult to balance miniaturization with efficient and stable ion transmission, and the performance of quadrupoles needs improvement. Summary of the Invention
[0003] The following is an overview of the subject matter described in detail in this disclosure. This overview is not intended to limit the scope of the claims.
[0004] This disclosure provides a simulation optimization method for a rectangular electrode quadrupole, which can effectively improve the ion transport capability and wide mass range detection capability of the quadrupole, enabling the mass spectrometer to achieve a balance between miniaturization and high performance.
[0005] This disclosure provides a simulation optimization method for a rectangular electrode quadrupole, including: Determine the physical parameters of the rectangular electrode quadrupole, and construct a geometric model of the rectangular electrode quadrupole based on the physical parameters, including the electrode width and electrode thickness; The geometric model of the rectangular electrode quadrupole is simplified, and the simplified geometric model of the rectangular electrode quadrupole is coupled between multiple physics fields to construct a parametric finite element model. Mesh the parameterized finite element model and set boundary parameters to establish a simulation optimization model. The simulation optimization model is used for electric field analysis and ion motion trajectory coupling. A reference electric field parameter is obtained, and the electrode width and electrode thickness are combined in a grid to obtain multiple sets of candidate electrode sizes. The simulation optimization model is called to perform ion transport efficiency simulation analysis on each set of candidate electrode sizes based on the reference electric field parameter to obtain the first ion transport efficiency corresponding to each set of candidate electrode sizes. The candidate electrode size corresponding to the optimal first ion transport efficiency is determined as the target electrode size. Multiple sets of candidate electric field parameters are determined, and the simulation optimization model is called to perform ion transport efficiency simulation analysis on each set of candidate electric field parameters based on the target electrode size to obtain the second ion transport efficiency corresponding to each set of candidate electric field parameters. The candidate electric field parameter corresponding to the optimal second ion transport efficiency is determined as the target electric field parameter. The simulation optimization model is used to perform ion transport efficiency simulation analysis based on the target electrode size and the target electric field parameters to obtain the target ion transport efficiency. The ion transport performance of the simulated and optimized rectangular electrode quadrupole is then verified based on the target ion transport efficiency.
[0006] In some embodiments of this disclosure, the parameterized finite element model is divided into multiple three-dimensional structured meshes. For each of the three-dimensional structured meshes, an ion potential distribution function is constructed based on the boundary parameters, and an ion motion control equation is constructed based on the ion potential distribution function. The ion potential distribution function is used to describe the change of potential at each position with time in the quadrupole field formed inside the rectangular electrode quadrupole, and the ion motion control equation is used to describe the motion law of ions in the quadrupole field and provide a basis for judging the stability of ions. Based on the topological relationships between the multiple three-dimensional structured grids, a simulation optimization model is established based on the corresponding ion motion control equations.
[0007] In some embodiments of this disclosure, the ion potential distribution function is determined based on the DC voltage amplitude, AC voltage amplitude, and angular frequency; A first dimensionless parameter and a second dimensionless parameter are introduced, and the ion motion control equation is determined based on the first dimensionless parameter, the second dimensionless parameter, and the ion potential distribution function. The first dimensionless parameter is determined by the DC voltage amplitude, and the second dimensionless parameter is determined by the AC voltage amplitude.
[0008] In some embodiments of this disclosure, a cosine operation is performed on the product of the angular frequency and the time variable to obtain a time oscillation term. The time oscillation term is then multiplied by the AC voltage amplitude, and the product result is added to the DC voltage amplitude to obtain a driving voltage term. The first position variable and the second position variable are subjected to a squared difference operation. The spatial distribution factor is determined based on the ratio of the squared difference operation result to the square of the quadrupole radius. The first position variable is the abscissa variable of the ion in the quadrupole cross section of the rectangular electrode quadrupole, and the second position variable is the ordinate variable of the ion in the quadrupole cross section of the rectangular electrode quadrupole. Set the quadrupole field weighting coefficient, and determine the ion potential distribution function based on the quadrupole field weighting coefficient, the driving voltage term, and the spatial distribution factor.
[0009] In some embodiments of this disclosure, an ion force equation is constructed based on the ion potential distribution function and the elementary charge, and the ion force equation and Newton's second law are combined to obtain the ion dynamics equation; The ion dynamics equations are simplified dimensionlessly based on the first dimensionless parameter and the second dimensionless parameter to obtain the ion motion control equations.
[0010] In some embodiments of this disclosure, the second-order acceleration of the ion in the first position direction is determined, the first electric field restoring force is determined based on the first dimensionless parameter, the second dimensionless parameter, the dimensionless time and the first position variable, and the first motion control sub-equation is determined based on the second-order acceleration in the first position direction and the first electric field restoring force. The second-order acceleration of the ion in the second position direction is determined. The second electric field restoring force is determined based on the first dimensionless parameter, the second dimensionless parameter, the dimensionless time, and the second position variable. The second motion control equation is determined based on the second-order acceleration in the second position direction and the second electric field restoring force. Determine the second-order acceleration of the ion in the third position direction, and determine the third motion control equation based on the second-order acceleration in the third position direction; By combining the first motion control equation, the second motion control equation, and the third motion control equation, the ion motion control equation is obtained.
[0011] In some embodiments of this disclosure, the quadrupole field radius of the rectangular electrode quadrupole is determined; Set the upper limit of the rectangle width and the upper limit of the rectangle thickness. Determine the electrode width of the rectangle based on the upper limit of the rectangle width and the electrode thickness of the rectangle based on the upper limit of the rectangle thickness. The length of the rectangular electrode quadrupole is set, and the physical parameters of the rectangular electrode are obtained based on the quadrupole radius, the electrode width, the electrode thickness, and the length of the rectangular electrode quadrupole.
[0012] In some embodiments of this disclosure, a cylindrical electrode quadrupole is constructed, and a voltage is applied to the cylindrical electrode to generate an equivalent quadrupole field; Determine the minimum distance from the surface of the cylindrical electrode to the center of the equivalent quadrupole field, and define the minimum distance as the quadrupole field radius of the rectangular electrode quadrupole.
[0013] The embodiments disclosed herein include at least the following beneficial effects: By determining the physical parameters of the rectangular electrode quadrupole and constructing a geometric model of the rectangular electrode quadrupole based on these physical parameters, a miniaturized model can be effectively constructed, laying a structural foundation for subsequent simulation optimization models. Simplifying the geometric model of the rectangular electrode quadrupole and coupling it with multiple physics fields to construct a parameterized finite element model effectively reduces the computational load and improves operational efficiency. Simultaneously, the integration of multiphysics field characteristics ensures the physical realism of the simulation. Next, meshing is performed on the parameterized finite element model, and boundary parameters are set to establish a simulation optimization model, realizing coupled simulation of electric field analysis and ion trajectory. Reference electric field parameters are obtained, and the electrode width and thickness are meshed to obtain multiple sets of candidate electrode sizes. The simulation optimization model is then used to perform ion transport efficiency simulation analysis on each set of candidate electrode sizes based on the reference electric field parameters, obtaining the first ion transport efficiency corresponding to each set of candidate electrode sizes. The candidate electrode size corresponding to the optimal first ion transport efficiency is determined as the target electrode size, enabling precise selection of the target electrode size that best matches the reference electric field parameters and has the optimal ion transport efficiency. Multiple sets of candidate electric field parameters are identified. A simulation optimization model is then used to perform ion transport efficiency simulation analysis on each set of candidate electric field parameters based on the target electrode size. The second ion transport efficiency corresponding to each set of candidate electric field parameters is obtained. The candidate electric field parameter corresponding to the optimal second ion transport efficiency is determined as the target electric field parameter. This allows for further screening of target electric field parameters that match the target electrode size, achieving joint optimization of the geometric structure and electric field parameters. Based on this, the simulation optimization model is used to perform ion transport efficiency simulation analysis based on the target electrode size and target electric field parameters, obtaining the target ion transport efficiency. The ion transport performance of the simulated and optimized rectangular electrode quadrupole is verified based on the target ion transport efficiency. This effectively improves the ion transport capability and wide mass range detection capability of the quadrupole, achieving a balance between miniaturization and high performance in the mass spectrometer.
[0014] Other features and advantages of this disclosure will be set forth in the following description and will be apparent in part from the description or may be learned by practicing this disclosure. Attached Figure Description
[0015] The accompanying drawings are provided to further understand the technical solutions of this disclosure and constitute a part of the specification. They are used together with the embodiments of this disclosure to explain the technical solutions of this disclosure and do not constitute a limitation on the technical solutions of this disclosure.
[0016] Figure 1 An optional flowchart for the simulation optimization method of rectangular electrode quadrupole provided in the embodiments of this disclosure; Figure 2This is an optional schematic diagram of a rectangular electrode quadrupole geometry model provided in an embodiment of this disclosure; Figure 3 A schematic diagram of an optional electrode structure for a simplified rectangular electrode quadrupole provided in this embodiment of the present disclosure; Figure 4 A schematic diagram of an optional structure for the cross-section of a rectangular electrode quadrupole and the distance between the quadrupole fields provided in an embodiment of this disclosure; Figure 5 This is an optional verification diagram illustrating the transmission efficiency over a wide quality range under optimal parameters provided in the embodiments of this disclosure. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this disclosure.
[0018] It should be noted that in the various specific embodiments of this disclosure, when processing is required based on data related to the characteristics of the target object, such as target object attribute information or a set of attribute information, the permission or consent of the target object will be obtained first. Furthermore, the collection, use, and processing of this data will comply with relevant laws, regulations, and standards. The target object can be a user. In addition, when embodiments of this disclosure require obtaining target object attribute information, separate permission or consent from the target object will be obtained through pop-ups or redirection to a confirmation page. Only after obtaining the target object's separate permission or consent will the necessary target object-related data for the normal operation of the embodiments of this disclosure be obtained.
[0019] In this disclosure, the terms "module" or "unit" refer to a computer program or part of a computer program that has a predetermined function and works with other related parts to achieve a predetermined goal, and can be implemented wholly or partially using software, hardware (such as processing circuitry or memory), or a combination thereof. Similarly, a processor (or multiple processors or memory) can be used to implement one or more modules or units. Furthermore, each module or unit can be part of an overall module or unit that includes the functionality of that module or unit.
[0020] To facilitate understanding of the technical solutions provided in the embodiments of this disclosure, some key terms used in the embodiments of this disclosure will be explained below: A mass spectrometer is a high-precision analytical instrument that performs qualitative and quantitative analysis and structural characterization of substances by measuring the mass-to-charge ratio (m / z) of charged particles. The principle involves ionizing the sample and then using electric and magnetic fields to separate and detect the ions, achieving precise analysis of the substance based on the differences in their mass-to-charge ratios.
[0021] The quadrupole is the core mass analysis component of a mass spectrometer. It consists of four symmetrically distributed electrode rods. By applying superimposed AC and DC voltages to the electrodes, a controllable quadrupole field is formed. The device utilizes the differences in the motion stability of ions with different mass-to-charge ratios in the quadrupole field to achieve ion screening and separation.
[0022] The quadrupole mass analyzer is a core component of a mass spectrometer, and its performance directly affects the spectrometer's sensitivity, resolution, and detection range. Current quadrupole mass spectrometers generally use hyperboloid or cylindrical quadrupoles. These two shapes require high manufacturing precision and are expensive. Furthermore, in the resulting ion transport system, the effective ion channel occupies a very small area across the entire cross-section, which is detrimental to the miniaturization of the mass spectrometer. In recent years, rectangular electrodes have attracted attention due to their ease of fabrication and compact structure; however, their electric field distribution easily introduces multipole field components, leading to field distortion and decreased ion transport efficiency. Moreover, existing optimization methods mostly target single mass-to-charge ratio ions or empirical parameter adjustments, lacking a systematic, wide-range mass simulation optimization process. This makes it difficult to simultaneously achieve mass spectrometer miniaturization and efficient, stable ion transport, thus the performance of the quadrupole needs further improvement.
[0023] Based on this, the present disclosure provides a simulation optimization method for a rectangular electrode quadrupole, which can effectively improve the ion transport capability and wide mass range detection capability of the quadrupole, enabling the mass spectrometer to achieve a balance between miniaturization and high performance.
[0024] Reference Figure 1 , Figure 1 This is an optional flowchart of a rectangular electrode quadrupole simulation optimization method provided in an embodiment of the present disclosure. The rectangular electrode quadrupole simulation optimization method includes, but is not limited to, the following steps S101 to S106.
[0025] Step S101: Determine the physical parameters of the rectangular electrode quadrupole and construct a geometric model of the rectangular electrode quadrupole based on the physical parameters.
[0026] The physical parameters of the rectangular electrode quadrupole include electrode width, electrode thickness, quadrupole distance, and rod length. Electrode width and electrode thickness are the dimensional parameters of the rectangular electrode; quadrupole distance is the minimum distance from the center of the ideal quadrupole field to the rectangular electrode; rod length is the axial length of a single electrode along the ion flight direction, i.e., the length of the rectangular electrode.
[0027] Specifically, the quadrupole distance is a key factor affecting the degree of electric field distortion. Therefore, when determining the physical parameters of a rectangular electrode quadrupole, the quadrupole distance must be determined first. When the electrode width of the rectangular electrode is sufficiently large, the electric field in the central region of the quadrupole will approach the electric field distribution of an ideal quadrupole. At this point, the potential of ions in an ideal quadrupole is... U represents the amplitude of the AC / DC voltage, and V represents the amplitude of the AC voltage. Here, ω is the angular frequency, and t is the time variable. Furthermore, electrode thickness also affects the degree of electric field distortion. It is important to note that unrestrictedly increasing the electrode width not only increases the overall size and cost of the quadrupole but also causes the suppression effect of electric field distortion to gradually saturate, resulting in a significant decrease in marginal benefits. Therefore, upper limits are pre-set for both the rectangular width and thickness. The electrode width of the rectangular electrode is determined based on the upper limit of the rectangular width, and the electrode thickness is determined based on the upper limit of the rectangular thickness, achieving a good balance between electric field performance and engineering practicality. In some embodiments, the upper limit of the rectangular width is set to 10.5 mm, and the upper limit of the rectangular thickness is set to 8 mm. Within the range of 8.5 to 10.5 mm, the suppression effect of electric field distortion becomes stronger as the electrode width increases.
[0028] In setting the rod length, a bidirectional correlation is observed between rod length and mass spectrometry performance. A longer rod length results in more cycles of ion movement within the quadrupole field, leading to better mass resolution. However, an excessively long rod length increases the probability of collisions between target ions and other ions within the quadrupole field, resulting in reduced ion transport efficiency. Therefore, to balance mass resolution and ion transport efficiency, the rod length of the rectangular electrode quadrupole is set independently.
[0029] Based on the quadrupole distance, electrode width, electrode thickness, and rod length, a rectangular electrode quadrupole geometric model is drawn in 3D modeling software, referring to... Figure 2 , Figure 2 This is an optional schematic diagram of a rectangular electrode quadrupole geometry provided in an embodiment of the present disclosure, including four plate-shaped electrodes (rectangular electrodes) and two retainers.
[0030] It is understandable that an ideal quadrupole consists of two pairs of symmetrically distributed hyperboloid electrodes. When a voltage is applied to the hyperboloid electrodes, a pure quadrupole field can be formed inside them. The potential distribution of the pure quadrupole field can be expressed by the following formula.
[0031] in, x Let x be the abscissa variable of the ion in the cross section of the quadrupole field. y Let be the ordinate variable of the ion within the cross-section of the quadrupole field. The radius of the pure quadrupole field is given. This pure quadrupole field possesses ideal hyperbolic electric field distribution characteristics, which is fundamental for achieving stable ion transport. However, the geometric characteristics of a rectangular electrode determine that it cannot directly generate an ideal quadrupole electric field. Therefore, it is necessary to perform an equivalent design on the rectangular electrode quadrupole to make the electric field distribution generated by the rectangular electrode quadrupole approximate the distribution state of an ideal quadrupole field. In one possible implementation, the hyperbolic electrode is simplified to a cylindrical electrode, a cylindrical electrode quadrupole is constructed, and a voltage is applied to the cylindrical electrode to generate an equivalent quadrupole field. The minimum distance from the surface of the cylindrical electrode to the center of the equivalent quadrupole field is determined, and this minimum distance is defined as the quadrupole field distance of the rectangular electrode quadrupole. In some embodiments, the radius of the cylindrical electrode is 6 mm, and the quadrupole field distance of the rectangular electrode quadrupole obtained with this cylindrical electrode radius is 5.325 mm.
[0032] Step S102: Simplify the geometric model of the rectangular electrode quadrupole, couple the simplified rectangular electrode quadrupole geometric model with multiple physics fields, and construct a parametric finite element model.
[0033] Specifically, the electrode structure and ion inlet end face of the rectangular electrode quadrupole geometric model are simplified. (Refer to...) Figure 2 , Figure 2 The cage in the middle has no significant effect on the distribution of the quadrupole field; removal Figure 2 The cage in the structure shown eliminates the influence of unnecessary geometric structures on the simulation calculation. The quadrupole electrodes are removed using Boolean difference operations in the simulation software, thus shortening the simulation calculation time. Simultaneously, a virtual end face with a thickness of 2mm is set at the entrance end of the quadrupole, and a preset voltage value is applied to this end face. This charged end face is used to construct the edge electric field during ion release, simulating the acceleration field of ions before entering the quadrupole field. This setting can match the initial motion state of ions in a real device, thereby improving the realism and reliability of the simulation method. The simplified rectangular electrode quadrupole geometric model can be referenced... Figure 3 , Figure 3 This is a schematic diagram of an optional electrode structure for a simplified rectangular electrode quadrupole provided in an embodiment of this disclosure. Based on this, refer to... Figure 4 , Figure 4 This is a schematic diagram of an optional structure for the cross-section of a rectangular electrode quadrupole and the distance between the quadrupole fields provided in an embodiment of this disclosure. The quadrupole radius of the rectangular electrode quadrupole (i.e., the quadrupole distance of this disclosure).
[0034] Next, the simplified rectangular electrode quadrupole geometric model is coupled with multiple physical fields such as frequency domain electric field and ion dynamics field to construct a parameterized finite element model.
[0035] Step S103: Perform mesh generation and set boundary parameters on the parametric finite element model to establish a simulation optimization model.
[0036] The boundary parameters include DC voltage amplitude, AC voltage amplitude, and angular frequency. The simulation optimization model is used for electric field analysis and ion motion trajectory coupling.
[0037] In one possible implementation, during the process of meshing and setting boundary parameters for the parametric finite element model to establish a simulation optimization model, the parametric finite element model can be divided into multiple three-dimensional structured meshes. For each three-dimensional structured mesh, an ion potential distribution function is constructed based on the boundary parameters. Based on the ion potential distribution function, an ion motion control equation is constructed. According to the topological relationship between the multiple three-dimensional structured meshes, a simulation optimization model is established based on the corresponding ion motion control equation. The ion potential distribution function describes the change of potential over time at various locations within the quadrupole field formed inside the rectangular electrode quadrupole, while the ion motion control equation describes the motion of ions in the quadrupole field and provides a basis for judging ion stability.
[0038] Specifically, the parametric finite element model is divided into multiple continuous and regular three-dimensional structured networks according to the characteristics of the electric field and the geometric structure. For example, the mesh can be generated based on the structure of the quadrupole field center region, the electrode edge distortion region, and the inlet acceleration field region. For each three-dimensional structured network, an ion potential distribution function is constructed based on the boundary parameters, and an ion motion control equation is constructed based on the ion potential distribution function. Based on the topological relationship between the multiple three-dimensional structured meshes, a simulation optimization model is established based on the corresponding ion motion control equation.
[0039] In one possible implementation, the process of constructing the ion potential distribution function based on boundary parameters and the ion motion control equation based on the ion potential distribution function can specifically involve determining the ion potential distribution function based on the DC voltage amplitude, AC voltage amplitude, and angular frequency, introducing a first dimensionless parameter and a second dimensionless parameter, and determining the ion motion control equation based on the first dimensionless parameter, the second dimensionless parameter, and the ion potential distribution function. The first dimensionless parameter is determined by the DC voltage amplitude, and the second dimensionless parameter is determined by the AC voltage amplitude.
[0040] Specifically, the ion potential distribution function is determined based on the DC voltage amplitude, AC voltage amplitude, and angular frequency. Simultaneously, a first dimensionless parameter and a second dimensionless parameter are introduced. The first dimensionless parameter... a and the second dimensionless parameter q It can be expressed by the following formula,
[0041] Where e is the elementary charge of the ion. Here, U represents the quadrupole field weight, U is the DC voltage amplitude, V is the AC voltage amplitude, and m is the ion mass. Angular frequency, The distance is the quadrupole field distance. The governing equations for ion motion are determined based on the first dimensionless parameter, the second dimensionless parameter, and the ion potential distribution function.
[0042] In one possible implementation, when determining the ion potential distribution function based on the DC voltage amplitude, AC voltage amplitude, and angular frequency, a cosine operation is performed on the product of the angular frequency and the time variable to obtain a time oscillation term. This time oscillation term is then multiplied by the AC voltage amplitude, and the product is added to the DC voltage amplitude to obtain the driving voltage term. A squared difference operation is performed on the first and second position variables, and the spatial distribution factor is determined based on the ratio of the squared difference result to the square of the quadrupole field radius. Quadrupole field weighting coefficients are set, and the ion potential distribution function is determined based on these coefficients, the driving voltage term, and the spatial distribution factor. Here, the first position variable is the abscissa variable of the ion within the quadrupole field cross-section of the rectangular electrode quadrupole, and the second position variable is the ordinate variable of the ion within the quadrupole field cross-section of the rectangular electrode quadrupole.
[0043] Specifically, the quadrupole field of a quadrupole is formed by applying voltages of equal magnitude but opposite polarity to two pairs of symmetrical electrodes. Introducing a rectangular electrode structure changes the multipole field, and the ion potential distribution function can be expressed by the following formula.
[0044] in, x As the first positional variable, y For the second position variable, t For time variables, It represents the weight of the quadrupole field. For time oscillation term, For the driving voltage term, This is the spatial distribution factor. When determining the specific values of the first position variable, the second position variable, and the time variable, the magnitude of the ion potential can be calculated using this ion potential distribution function.
[0045] In one possible implementation, when determining the ion motion control equation based on the first dimensionless parameter, the second dimensionless parameter, and the ion potential distribution function, the ion force equation is constructed based on the ion potential distribution function and the elementary charge. The ion force equation and Newton's second law are then combined to obtain the ion dynamics equation. The ion dynamics equation is then simplified dimensionlessly based on the first and second dimensionless parameters to obtain the ion motion control equation.
[0046] Specifically, the force equation for ions can be expressed by the following formula.
[0047] in, For elementary charge, Let be the potential gradient. Since the motion of charged particles in a quadrupole field follows Newton's second law, combining the force equation of the ion with Newton's second law yields the ion dynamics equation. The ion dynamics equations are simplified dimensionlessly based on the first and second dimensionless parameters to obtain the ion motion control equations.
[0048] In one possible implementation, the ion motion control equation consists of multiple sub-equations, specifically the standard Matthews equation. First, the second-order acceleration of the ion in the first position direction is determined. Then, the first electric field restoring force is determined based on the first dimensionless parameter, the second dimensionless parameter, the dimensionless time, and the first position variable. Finally, the first motion control sub-equation is determined based on the second-order acceleration in the first position direction and the first electric field restoring force. This first motion control sub-equation can be expressed by the following formula.
[0049] The first position direction is radial. x , a The first dimensionless parameter, q The second dimensionless parameter, Dimensionless time, dimensionless time Specifically, it can be done through the formula. calculate. This represents the second-order acceleration of the ion in the direction of the first position. This is the restoring force of the first electric field.
[0050] The second-order acceleration of the ion in the second position direction is determined. The second electric field restoring force is determined based on the first dimensionless parameter, the second dimensionless parameter, the dimensionless time, and the second position variable. The second motion control equation is then determined based on the second-order acceleration in the second position direction and the second electric field restoring force. The second motion control equation can be expressed by the following formula.
[0051] The second position direction is radial. y , This represents the second-order acceleration of the ion in the direction of the second position. This is the restoring force of the second electric field.
[0052] Determine the second-order acceleration of the ion in the third position direction, and then determine the third motion control equation based on this second-order acceleration. The third motion control equation can be expressed by the following formula.
[0053] The third position direction is axial- z Due to the potential distribution It is independent of the third position direction, and only requires the second-order acceleration of the ion in the third position direction. To determine the third control equation.
[0054] By simultaneously solving the first, second, and third motion control equations, the ion motion control equation is obtained. Solving the ion motion control equation, the stability of the ion is determined solely by the values of the first and second dimensionless parameters (a, q). When (a, q) falls within the first stability region, the ion can stably pass through the quadrupole field.
[0055] Step S104: Obtain the reference electric field parameters, perform meshing combination of electrode width and electrode thickness to obtain multiple sets of candidate electrode sizes, call the simulation optimization model to perform ion transport efficiency simulation analysis on each set of candidate electrode sizes based on the reference electric field parameters, obtain the first ion transport efficiency corresponding to each set of candidate electrode sizes, and determine the candidate electrode size corresponding to the optimal first ion transport efficiency as the target electrode size.
[0056] Specifically, a gridded scanning combination is performed on the electrode width and thickness. The value ranges and scanning step sizes for electrode width and thickness are set. The scanning step size controls the scanning accuracy. Based on the value ranges and scanning step sizes, a gridded parameter combination is generated, resulting in multiple sets of candidate electrode sizes. For example, if the electrode width range is 6mm~10mm and the scanning step size is 1mm, and the electrode thickness range is 3mm~5mm and the scanning step size is 0.5mm, the set of electrode width values is W={6,7,8,9,10}, and the set of electrode thickness values is H={3.0, 3.5,4.0, 4.5, 5.0}. Based on sets W and H, 5×5=25 sets of candidate electrode sizes are generated.
[0057] Next, the simulation optimization model is called to perform ion transport efficiency simulation analysis on each group of candidate electrode sizes to obtain the first ion transport efficiency corresponding to each group of candidate electrode sizes. The candidate electrode size corresponding to the optimal first ion transport efficiency is determined as the target electrode size.
[0058] Step S105: Determine multiple sets of candidate electric field parameters, and use the simulation optimization model to perform ion transport efficiency simulation analysis on each set of candidate electric field parameters based on the target electrode size. Obtain the second ion transport efficiency corresponding to each set of candidate electric field parameters, and determine the candidate electric field parameter corresponding to the optimal second ion transport efficiency as the target electric field parameter. The candidate electric field parameters include a first dimensionless parameter, radio frequency, and ion incident energy.
[0059] Specifically, the electric field parameters are meshed and combined to obtain multiple sets of candidate electric field parameters. The meshing and combination method is similar to that in step S104 and will not be repeated here. Under the condition of the target electrode size, the simulation optimization model is called to optimize the first dimensionless parameter in each set. a Radio frequency f and ion incident energy E Ion transport efficiency simulation analysis was performed to obtain the second ion transport efficiency corresponding to each group of candidate electric field parameters. The candidate electric field parameter corresponding to the optimal second ion transport efficiency was determined as the target electric field parameter.
[0060] Step S106: Call the simulation optimization model to perform ion transport efficiency simulation analysis based on the target electrode size and target electric field parameters, obtain the target ion transport efficiency, and verify the ion transport performance of the simulated optimized rectangular electrode quadrupole based on the target ion transport efficiency.
[0061] The target electrode size obtained in step S104 and the target electric field parameters obtained in step S105 are fused. A simulation optimization model is then used to perform ion transport efficiency simulation analysis on these fused parameters to obtain the target ion transport efficiency. The original ion transport efficiency before simulation optimization is obtained, and the feasibility of the simulation optimization model is verified based on the comparison between the target ion transport efficiency and the original ion transport efficiency. (Refer to...) Figure 5 , Figure 5 This diagram illustrates an optional verification of the transport efficiency over a wide mass range under optimal parameters provided in this embodiment. The horizontal axis represents the mass-to-charge ratio (m / z) of the ions, with a higher value indicating a higher mass-to-charge ratio. The vertical axis represents the ion transport efficiency (%), representing the proportion of ions successfully transported from the quadrupole inlet to the outlet. In the m / z ratio range of 70–120, the transport efficiency fluctuates slightly but remains relatively stable, hovering between 80% and 90%, indicating stable ion transport performance within this range. Two distinct efficiency peaks appear in the m / z ratio range of 20–70, with transport efficiencies exceeding 90% near m / z 30 and m / z 60, indicating a good match between the ions in this range and the current quadrupole field.
[0062] In summary, the rectangular electrode quadrupole simulation optimization method provided in this disclosure optimizes the rectangular electrode quadrupole through parametric modeling and multi-physics coupling. Compared to existing optimization methods that only adjust parameters for a single ion, this performance simulation optimization method constructs an optimization process encompassing "geometric structure - electric field distribution - ion trajectory - ion transport efficiency." Furthermore, a two-stage optimization strategy is proposed. The first stage, based on fixed reference electric field parameters, studies the influence of the rectangular electrode size on the quadrupole's ion transport efficiency, thereby determining the target electrode size for optimal ion transport efficiency. The second stage, based on the target electrode size determined in the first stage, studies the influence of changes in electric field parameters on the wide mass-to-charge ratio ion transport efficiency, thereby determining the target electric field parameters for optimal ion transport efficiency. Finally, the target electrode size and target electric field parameters are fused to simulate and verify the optimized rectangular electrode quadrupole's ion transport efficiency. For rectangular electrode quadrupoles, this method effectively improves the quadrupole's ion transport capability and wide mass range detection capability, achieving a balance between miniaturization and high performance in mass spectrometers, providing key technical support for mass spectrometer miniaturization research.
[0063] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in this disclosure and the foregoing drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate to describe embodiments of this disclosure, for example, those that can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatuses.
[0064] It should be understood that in this disclosure, "at least one item" means one or more, and "more than one" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.
[0065] It should be understood that in the description of the embodiments of this disclosure, "multiple" means two or more, "greater than", "less than", "exceeding" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself.
[0066] In the embodiments provided in this disclosure, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.
[0067] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.
[0068] Furthermore, the functional units in the various embodiments of this disclosure can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.
[0069] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this disclosure, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this disclosure. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.
[0070] It should also be understood that the various implementation methods provided in this disclosure can be combined arbitrarily to achieve different technical effects.
[0071] The above is a detailed description of the preferred embodiments of this disclosure. However, this disclosure is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this disclosure. All such equivalent modifications or substitutions are included within the scope defined by the claims of this disclosure.
Claims
1. A simulation optimization method for a rectangular electrode quadrupole, characterized in that, include: Determine the physical parameters of the rectangular electrode quadrupole, and construct a geometric model of the rectangular electrode quadrupole based on the physical parameters, including the electrode width and electrode thickness; The geometric model of the rectangular electrode quadrupole is simplified, and the simplified geometric model of the rectangular electrode quadrupole is coupled between multiple physics fields to construct a parametric finite element model. Mesh the parameterized finite element model and set boundary parameters to establish a simulation optimization model. The simulation optimization model is used for electric field analysis and ion motion trajectory coupling. A reference electric field parameter is obtained, and the electrode width and electrode thickness are combined in a grid to obtain multiple sets of candidate electrode sizes. The simulation optimization model is called to perform ion transport efficiency simulation analysis on each set of candidate electrode sizes based on the reference electric field parameter to obtain the first ion transport efficiency corresponding to each set of candidate electrode sizes. The candidate electrode size corresponding to the optimal first ion transport efficiency is determined as the target electrode size. Multiple sets of candidate electric field parameters are determined, and the simulation optimization model is called to perform ion transport efficiency simulation analysis on each set of candidate electric field parameters based on the target electrode size to obtain the second ion transport efficiency corresponding to each set of candidate electric field parameters. The candidate electric field parameter corresponding to the optimal second ion transport efficiency is determined as the target electric field parameter. The simulation optimization model is used to perform ion transport efficiency simulation analysis based on the target electrode size and the target electric field parameters to obtain the target ion transport efficiency. The ion transport performance of the simulated and optimized rectangular electrode quadrupole is then verified based on the target ion transport efficiency.
2. The simulation optimization method for a rectangular electrode quadrupole according to claim 1, wherein performing mesh generation and setting boundary parameters on the parameterized finite element model to establish the simulation optimization model includes: The parameterized finite element model is divided into multiple three-dimensional structured meshes. For each of the three-dimensional structured meshes, an ion potential distribution function is constructed based on the boundary parameters. An ion motion control equation is constructed based on the ion potential distribution function. The ion potential distribution function is used to describe the change of potential at each position with time in the quadrupole field formed inside the rectangular electrode quadrupole. The ion motion control equation is used to describe the motion law of ions in the quadrupole field and to provide a basis for judging the stability of ions. Based on the topological relationships between the multiple three-dimensional structured grids, a simulation optimization model is established based on the corresponding ion motion control equations.
3. The simulation optimization method for rectangular electrode quadrupoles according to claim 2, characterized in that, The boundary parameters include DC voltage amplitude, AC voltage amplitude, and angular frequency. The construction of an ion potential distribution function based on these boundary parameters, and the construction of ion motion control equations based on the ion potential distribution function, include: The ion potential distribution function is determined based on the DC voltage amplitude, AC voltage amplitude, and angular frequency. A first dimensionless parameter and a second dimensionless parameter are introduced, and the ion motion control equation is determined based on the first dimensionless parameter, the second dimensionless parameter, and the ion potential distribution function. The first dimensionless parameter is determined by the DC voltage amplitude, and the second dimensionless parameter is determined by the AC voltage amplitude.
4. The simulation optimization method for rectangular electrode quadrupoles according to claim 3, characterized in that, The determination of the ion potential distribution function based on the DC voltage amplitude, the AC voltage amplitude, and the angular frequency includes: Perform a cosine operation on the product of the angular frequency and the time variable to obtain the time oscillation term. Multiply the time oscillation term by the AC voltage amplitude and add the product result to the DC voltage amplitude to obtain the driving voltage term. The first position variable and the second position variable are subjected to a squared difference operation. The spatial distribution factor is determined based on the ratio of the squared difference operation result to the square of the quadrupole radius. The first position variable is the abscissa variable of the ion in the quadrupole cross section of the rectangular electrode quadrupole, and the second position variable is the ordinate variable of the ion in the quadrupole cross section of the rectangular electrode quadrupole. Set the quadrupole field weighting coefficient, and determine the ion potential distribution function based on the quadrupole field weighting coefficient, the driving voltage term, and the spatial distribution factor.
5. The simulation optimization method for rectangular electrode quadrupoles according to claim 3, characterized in that, The step of determining the ion motion control equation based on the first dimensionless parameter, the second dimensionless parameter, and the ion potential distribution function includes: Based on the ion potential distribution function and elementary charge, construct the ion force equation, and combine the ion force equation with Newton's second law to obtain the ion dynamics equation. The ion dynamics equations are simplified dimensionlessly based on the first dimensionless parameter and the second dimensionless parameter to obtain the ion motion control equations.
6. The simulation optimization method for rectangular electrode quadrupoles according to claim 5, characterized in that, The ion motion control equation consists of multiple sub-equations, and the rectangular electrode quadrupole simulation optimization method further includes: The second-order acceleration of the ion in the first position direction is determined, and the first electric field restoring force is determined based on the first dimensionless parameter, the second dimensionless parameter, the dimensionless time, and the first position variable. The first motion control equation is determined based on the second-order acceleration in the first position direction and the first electric field restoring force. The second-order acceleration of the ion in the second position direction is determined. The second electric field restoring force is determined based on the first dimensionless parameter, the second dimensionless parameter, the dimensionless time, and the second position variable. The second motion control equation is determined based on the second-order acceleration in the second position direction and the second electric field restoring force. Determine the second-order acceleration of the ion in the third position direction, and determine the third motion control equation based on the second-order acceleration in the third position direction; By combining the first motion control equation, the second motion control equation, and the third motion control equation, the ion motion control equation is obtained.
7. The simulation optimization method for rectangular electrode quadrupoles according to claim 1, characterized in that, The physical parameters also include the quadrupole distance and rod length. The physical parameters for determining the rectangular electrode quadrupole include: Determine the quadrupole field radius of the rectangular electrode quadrupole; Set the upper limit of the rectangle width and the upper limit of the rectangle thickness. Determine the electrode width of the rectangle based on the upper limit of the rectangle width and the electrode thickness of the rectangle based on the upper limit of the rectangle thickness. The length of the rectangular electrode quadrupole is set, and the physical parameters of the rectangular electrode are obtained based on the quadrupole radius, the electrode width, the electrode thickness, and the length of the rectangular electrode quadrupole.
8. The simulation optimization method for rectangular electrode quadrupoles according to claim 7, characterized in that, The determination of the quadrupole field radius of the rectangular electrode quadrupole includes: Construct a cylindrical electrode quadrupole, apply a voltage to the cylindrical electrode to generate an equivalent quadrupole field; Determine the minimum distance from the surface of the cylindrical electrode to the center of the equivalent quadrupole field, and define the minimum distance as the quadrupole field radius of the rectangular electrode quadrupole.