Soil multi-element detection method and system

Abstract

The invention discloses a soil multi-element detection method and system.The method comprises the steps that an ion source system is matched with a pulse generator to generate a primary ion beam to bombard the surface of an original soil sample, and secondary ions are generated; the secondary ions enter the reflective time-of-flight mass analyzer after being adjusted and focused by the ion transmission system, and high-resolution mass spectrum detection is realized through the ion detector; and detected signals are transmitted to a mobile phone terminal for intelligent analysis, so that multi-element detection of the soil is realized. The soil is detected by adopting the time-of-flight secondary ion mass spectrometry, elements and isotopes with extremely low concentrations can be detected, meanwhile, the method has the advantages of non-destructiveness, rapidness and the like, and rapid analysis can be carried out under the condition that a sample is not damaged.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural detection, and in particular relates to a soil multi-element detection method and system. Background Art

[0002] With the rapid development of industrialization and urbanization, environmental pollution problems have become increasingly prominent, among which soil pollution is particularly serious. Soil pollution not only affects the growth of crops, but may also affect human health through the food chain. Heavy metal pollution in the soil is easy to enrich and is difficult to be decomposed by organisms, which will cause great damage to the structure of the soil. These heavy metals enter crops and affect food safety. Therefore, accurate detection of the content of heavy metals and other harmful substances in the soil is of great significance for evaluating soil quality, formulating pollution prevention and control measures, and ensuring food safety.

[0003] However, most existing technologies use physical methods such as X-ray fluorescence spectroscopy and laser induced breakdown spectroscopy. Although they are simple to operate and fast to analyze, they have a long detection cycle and low accuracy when analyzing multiple elements simultaneously. Chemical methods such as atomic absorption spectroscopy quantitatively analyze the element content of soil by measuring the absorption spectrum of elements at specific wavelengths. Although they are highly sensitive and accurate, they are complex to operate and require professional laboratory equipment. Moreover, these devices can only be interpreted and recommended by professionals, resulting in knowledge limitations and no substantial effect.

[0004] Therefore, how to quickly and accurately achieve multi-element detection of soil is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0005] In order to solve the above technical problems, this application proposes the following technical solutions:

[0006] In a first aspect, the present application provides a soil multi-element detection method, comprising:

[0007] The ion source system cooperates with a pulse generator to generate a primary ion beam to bombard the surface of the original soil sample to generate secondary ions;

[0008] The secondary ions are adjusted and focused by the ion transmission system and then enter the reflective time-of-flight mass analyzer, and are detected by a high-resolution mass spectrometer through an ion detector;

[0009] The detected signals are transmitted to the mobile phone for intelligent analysis to realize multi-element detection of soil.

[0010] In a possible implementation, the ion source system cooperates with a pulse generator to generate a primary ion beam to bombard the surface of the original soil sample to generate secondary ions, including:

[0011] Transmitting the pulse signal generated by the pulse generator to the corresponding electrodes of the ion source system;

[0012] Modulate the ion generation and acceleration process to produce a pulsed primary ion beam;

[0013] The surface of the original soil sample is bombarded by the primary ion beam to generate secondary ions.

[0014] In a possible implementation, the secondary ions are adjusted and focused by the ion transmission system and then enter the reflective time-of-flight mass analyzer, and high-resolution mass spectrometry is performed by the ion detector, including:

[0015] Extracting secondary ions entering the reflectron time-of-flight mass analyzer;

[0016] The time when each secondary ion arrives at the ion detector is obtained respectively;

[0017] Different types of secondary ions are separated according to the time of arrival at the ion detector to achieve high-resolution mass spectrometry detection.

[0018] In a possible implementation, the calculation formula for respectively obtaining the time when each secondary ion reaches the ion detector is:

[0019]

[0020] Among them, L1 and L2 are distance parameters, K1 is the kinetic energy after passing through the first-stage deceleration electric field, and K (ref) is the reference energy in the field-free drift region, δ is the energy divergence component, m is the mass of the secondary ion, D1 is the distance between the primary time focusing plane and the ion reflector entrance, and D2 is the distance between the ion reflector exit and the ion detector.

[0021] In a possible implementation, the adjustment focusing conditions of the secondary ions passing through the ion transmission system are:

[0022]

[0023] In a possible implementation, the detected signal is transmitted to a mobile phone for intelligent analysis to achieve multi-element detection of soil, including:

[0024] The detected signal is converted into a mass spectrum and then transmitted to the mobile phone for peak identification, peak intensity calculation and background subtraction operations;

[0025] The detected substances, elements and corresponding content percentages in the soil are displayed on the mobile phone, realizing multi-element detection of soil.

[0026] In a second aspect, an embodiment of the present application provides a soil multi-element detection system, comprising:

[0027] primary ion optics, injection system, vacuum system, secondary ion transport system, reflectron time-of-flight mass analyzer, ion detector and cell phone;

[0028] The primary ion optical system is used to generate a pulsed primary ion beam to bombard the surface of the original soil sample to generate secondary ions;

[0029] The sample introduction system is used to place and transmit soil samples;

[0030] The vacuum system is used to provide a vacuum environment to reduce the collision between ions and gas molecules;

[0031] The secondary ion transmission system is used to transmit secondary ions;

[0032] The reflectron time-of-flight mass analyzer is used to determine the mass of ions by measuring the flight time of ions;

[0033] The ion detector is used to separate different types of ions according to the mass and charge ratio of the ions.

[0034] In a possible implementation, the mobile phone is provided with an agricultural planting option and a heavy metal detection option.

[0035] The agricultural planting option is used to provide soil fertility and planting suggestions based on the substances, elements and corresponding content percentages detected in the soil;

[0036] The heavy metal detection option is used to display the content of heavy metals in the soil and methods to improve the soil.

[0037] Compared with the prior art, the beneficial effects of this application are:

[0038] This application uses time-of-flight secondary ion mass spectrometry to detect soil, which can detect extremely low concentrations of elements and isotopes. It also has the advantages of being non-destructive and rapid, and can perform rapid analysis without destroying the sample.

[0039] The intelligent multi-element soil detection system based on time-of-flight secondary ion mass spectrometry technology in this application makes soil detection rapid, and at the same time performs intelligent analysis based on the detected data to provide improvement suggestions for agricultural planting and heavy metal contaminated soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic diagram of a process for detecting multiple elements in soil provided in an embodiment of the present application;

[0041] Figure 2 A schematic diagram of secondary ion generation provided in an embodiment of the present application;

[0042] Figure 3 A schematic diagram of the working principle of a reflection-type time-of-flight mass analyzer with a two-stage deceleration electric field provided in an embodiment of the present application;

[0043] Figure 4 Schematic diagram of the soil multi-element detection system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] The present solution is described below in conjunction with the accompanying drawings and specific implementation methods.

[0045] Figure 1 A flow chart of a soil multi-element detection method provided in the present application is shown in FIG. Figure 1 The soil multi-element detection method in this embodiment includes:

[0046] S101, using an ion source system in conjunction with a pulse generator to generate a primary ion beam to bombard the surface of the original soil sample to generate secondary ions.

[0047] In this embodiment, an untreated original soil sample is taken and aligned with a primary ion emission pipe. A gas (such as argon) is introduced into the ion source chamber and ionized by radio frequency discharge or electron collision. Subsequently, the ion beam after ionization is controlled by a pulse power supply so that it is emitted in a pulsed form. In this embodiment, see Figure 2 ,The pulse generator can be connected to the power system of the ion source system to modulate the ion generation and acceleration process to generate a suitable pulsed primary ion beam, which bombards the surface of the original soil sample through the primary ion beam to generate secondary ions.

[0048] This embodiment generates a pulsed ion beam that meets the experimental requirements by precisely controlling the pulse width, frequency, amplitude and other parameters. The secondary ions generated in this way also appear in the form of pulses. By precisely controlling the pulse time and frequency, the secondary ions can be set off at the same time starting point, so that their masses can be accurately measured based on their flight time.

[0049] S102, the secondary ions are adjusted and focused by the ion transmission system and then enter the reflective time-of-flight mass analyzer, and are detected by a high-resolution mass spectrometer through an ion detector.

[0050] In this embodiment, secondary ions entering the reflective time-of-flight mass analyzer are extracted, and the time when each secondary ion arrives at the ion detector is obtained. Different types of secondary ions are separated according to the time of arrival at the ion detector to achieve high-resolution mass spectrometry detection.

[0051] Since the linear time-of-flight mass analyzer has defects such as simple structure and low resolution, in order to improve its resolution, this embodiment will adopt a reflective time-of-flight mass analyzer, which structurally lengthens the flight distance of ions, prolongs the corresponding ion flight time, and has more parameters for easy detection.

[0052] The simplest reflective time-of-flight mass analyzer contains only one uniform deceleration electric field. The distance between the primary time focusing plane and the entrance of the ion reflector is D1, and the distance between the exit of the ion reflector and the detector is D2. The ions fly from the primary time focusing plane through the field-free drift region into the reflector, and after reflection, they are emitted from the reflector and then reach the ion detector through the field-free drift region. In the field-free drift region, the flight time of the ions is reduced by increasing the kinetic energy of the ions. However, in the reflector, the ions with greater energy, although they have a greater movement speed, pass a longer distance, so the flight time of the ions increases with the increase of energy. By reasonably selecting the relationship between the flight distance of the ions in the field-free drift region and the reflector, the first-order approximation of the flight time to the energy dispersion can be eliminated.

[0053] Assume that the charge of an ion with a mass of m is Q and the energy of the ion in the time focusing plane is K. (ref) , the energy divergence component is δ. Through simple calculation, the flight time of the ion from the primary time focusing plane to the ion detector position is:

[0054]

[0055] Where L is the reference energy K on the Z axis (ref) The distance from the entrance of the reflector to the turning point of the reverse motion of the ions.

[0056] When the first-order time focusing condition is met, that is, when (t|δ) = 0, the relationship between the flight distance of ions in the field-free drift region and the reflector can be calculated as:

[0057] D1+D2=4L

[0058] In this case, the second-order component of energy dispersion to flight time is:

[0059] (t|δδ)=t(ref) / 4

[0060] See also Figure 3 , a schematic diagram of the working principle of a reflective time-of-flight mass analyzer with a two-stage deceleration electric field provided in an embodiment of the present application, assuming that the mass of an ion is m and the charge is Q, the kinetic energy of an ion after passing through a first-stage deceleration electric field is K1, and the reference energy in the field-free drift region is K (ref), the energy divergence component is δ, then the flight time of the ion to the detector is:

[0061]

[0062] Among them, L1 and L2 are distance parameters, K1 is the kinetic energy after passing through the first-stage deceleration electric field, and K (ref) is the reference energy in the field-free drift region.

[0063] When (t|δδ) = 0, that is, when the second-order time focusing of ions is satisfied, the required conditions are as follows:

[0064]

[0065] Obviously, the necessary conditions for satisfying second-order focusing are:

[0066] K1 / K (ref) <1 / 3.

[0067] S103, transmitting the detected signal to the mobile phone for intelligent analysis to achieve multi-element detection of soil.

[0068] In this embodiment, the detected signal is converted into a mass spectrum and then transmitted to a mobile phone for peak identification, peak intensity calculation and background subtraction operations. The detected substances, elements and corresponding content percentages in the soil are displayed on the mobile phone to achieve multi-element detection of the soil.

[0069] Corresponding to the soil multi-element detection method provided in the above embodiment, the present application also provides an embodiment of a soil multi-element detection system.

[0070] See also Figure 4 The soil multi-element detection system provided in this embodiment includes: a primary ion optical system, an injection system, a vacuum system, a secondary ion transmission system, a reflective time-of-flight mass analyzer, an ion detector and a mobile phone. Among them, the primary ion optical system is used to generate a pulsed primary ion beam and then bombard the surface of the original soil sample to generate secondary ions. The injection system is equipped with a sample stage and a sample transmission device for placing and transmitting samples. The position and angle of the sample stage can be adjusted to analyze different areas and ensure that the sample can accurately enter the analysis area. The sample transmission device is responsible for introducing the sample from the outside into the analysis area. The injection chamber of the injection system needs to maintain a high vacuum environment to reduce the interference of external gases on the analysis process for placing and transmitting soil samples.

[0071] The vacuum system is used to provide a vacuum environment to ensure that the primary ion beam and secondary ions can be transmitted and analyzed without interference from external gases. At the same time, the high vacuum environment can reduce the collision between ions and gas molecules and improve the accuracy and sensitivity of the analysis. The secondary ion transmission system is used to transmit secondary ions.

[0072] The reflective time-of-flight mass analyzer is used to determine the mass of ions by measuring their flight time. Since the speed of a given ion is inversely proportional to its mass, ions of different masses take different flight times in the drift tube, and heavier ions arrive at the detector later than lighter ions. The mass of the ions is determined by measuring the flight time. The ion detector is used to separate different types of ions based on their mass and charge ratio. In addition, the phone also has an agricultural planting option and a heavy metal detection option. The agricultural planting option is used to give soil fertility and planting recommendations based on the substances and elements detected in the soil and the corresponding content percentages. The heavy metal detection option is used to display the content of heavy metals in the soil and ways to improve the soil.

[0073] In the embodiments of the present application, "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0074] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0075] The above is only a specific implementation of the present application. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. The protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A soil multi-element detection method, characterized in that: include: The ion source system cooperates with a pulse generator to generate a primary ion beam to bombard the surface of the original soil sample to generate secondary ions; The secondary ions are adjusted and focused by the ion transmission system and then enter the reflective time-of-flight mass analyzer, and are detected by a high-resolution mass spectrometer through an ion detector; The detected signals are transmitted to the mobile phone for intelligent analysis to achieve multi-element detection of soil.

2. The soil multi-element detection method according to claim 1, characterized in that: The method comprises: generating a primary ion beam by using an ion source system in cooperation with a pulse generator to bombard the surface of the original soil sample to generate secondary ions, including: Transmitting the pulse signal generated by the pulse generator to the corresponding electrodes of the ion source system; Modulate the ion generation and acceleration process to produce a pulsed primary ion beam; The surface of the original soil sample is bombarded by the primary ion beam to generate secondary ions.

3. The soil multi-element detection method according to claim 1, characterized in that: The secondary ions are adjusted and focused by the ion transmission system and then enter the reflective time-of-flight mass analyzer, and are detected by a high-resolution mass spectrometer through an ion detector, including: Extracting secondary ions entering the reflectron time-of-flight mass analyzer; The time when each secondary ion arrives at the ion detector is obtained respectively; Different types of secondary ions are separated according to the time of arrival at the ion detector to achieve high-resolution mass spectrometry detection.

4. The soil multi-element detection method according to claim 3, characterized in that: Including, the calculation formula for obtaining the time when each secondary ion arrives at the ion detector is: Among them, L1 and L2 are distance parameters, K1 is the kinetic energy after passing through the first-stage deceleration electric field, and K (ref) is the reference energy in the field-free drift region, δ is the energy divergence component, m is the mass of the secondary ion, D1 is the distance between the primary time focusing plane and the ion reflector entrance, and D2 is the distance between the ion reflector exit and the ion detector.

5. The soil multi-element detection method according to claim 1, characterized in that: include: The adjustment focusing conditions of secondary ions passing through the ion transmission system are:

6. The soil multi-element detection method according to claim 1, characterized in that: The detected signal is transmitted to the mobile phone for intelligent analysis to realize multi-element detection of soil, including: The detected signal is converted into a mass spectrum and then transmitted to the mobile phone for peak identification, peak intensity calculation and background subtraction operations; The detected substances, elements and corresponding content percentages in the soil are displayed on the mobile phone, realizing multi-element detection of soil.

7. A soil multi-element detection system, based on the soil multi-element detection method according to any one of claims 1 to 6, characterized in that: include: primary ion optics, injection system, vacuum system, secondary ion transport system, reflectron time-of-flight mass analyzer, ion detector and cell phone; The primary ion optical system is used to generate a pulsed primary ion beam to bombard the surface of the original soil sample to generate secondary ions; The sample introduction system is used to place and transmit soil samples; The vacuum system is used to provide a vacuum environment to reduce the collision between ions and gas molecules; The secondary ion transmission system is used to transmit secondary ions; The reflectron time-of-flight mass analyzer is used to determine the mass of ions by measuring the flight time of ions; The ion detector is used to separate different types of ions according to the mass and charge ratio of the ions.

8. The soil multi-element detection system according to claim 7, characterized in that: include: The mobile phone is provided with an agricultural planting option and a heavy metal detection option. The agricultural planting option is used to provide soil fertility and planting suggestions based on the substances, elements and corresponding content percentages detected in the soil; The heavy metal detection option is used to display the content of heavy metals in the soil and methods to improve the soil.

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