Dual time-of-flight mass spectrometer and detection method

Abstract

The invention discloses a dual time-of-flight mass spectrometer and a detection method. The mass spectrometer comprises an ion generation transmission area, a first time-of-flight mass spectrometry analysis area, a secondary ion transmission area and a second time-of-flight mass spectrometry analysis area, the ion generation and transmission area is used for generating ions to be detected and transmitting the ions to be detected to the first time-of-flight mass spectrometry area; the first time-of-flight mass spectrometry analysis area is used for carrying out time-of-flight mass spectrometry analysis on the to-be-detected ions expelled by the ion generation and transmission area; the secondary ion transmission area is used for transmitting the to-be-detected ions penetrating through the reflecting area of the first time-of-flight mass spectrometry area to the second time-of-flight mass spectrometry area; and the second time-of-flight mass spectrometry analysis area is used for carrying out time-of-flight mass spectrometry refinement analysis on the to-be-detected ions penetrating through the reflecting area of the first time-of-flight mass spectrometry analysis area. According to the invention, a wide mass-to-charge ratio measurement range and fine measurement of a signal of a certain section of mass-to-charge ratio can be simultaneously realized through double mass spectrometry.

Description

Technical Field

[0001] The present invention relates to the field of proton transfer mass spectrometry, and particularly to a dual time-of-flight mass spectrometer. Background Art

[0002] Mass spectrometry technology is an effective and universal experimental technique, which has been widely applied in research fields such as chemistry, physics, and biology.

[0003] PTR mass spectrometry (Proton Transfer Reaction Mass Spectrometry) is a technique for detecting compounds in the gas phase, and is usually used for rapid and highly sensitive gas-phase analysis. In the PTR technique, the compound to be detected undergoes a proton transfer reaction with a proton transfer reagent (usually H3O + ) to generate ionized products.

[0004] Specifically, the initial reaction ions generated by the ion source undergo a proton transfer reaction with the analyte M molecules in the drift tube to ionize the analyte, as shown in the following equation:

[0005]

[0006] Among them, M is the analyte molecule, and k is the proton transfer reaction rate constant. Then the relationship between the concentration and time change of the ion product [MH + in the drift tube is:

[0007]

[0008] It can be deduced that the concentration of the volatile organic compound M in the drift tube is:

[0009]

[0010] Among them, and are the ion intensities of H3O + and MH + detected by the mass spectrometer respectively, t is the reaction time of the ions in the drift tube, and α is the response factor of the mass spectrometer to the ion product MH + . The quantitative determination of the concentration of the analyte M can be achieved by the partial pressure concentration of M measured by PTR-MS.

[0011] A time-of-flight mass spectrometer (TOFMS) is a commonly used mass spectrometer, and its principle is to determine the mass of ions according to the flight time of ions in an electric field. In TOFMS, the mass-to-charge ratio (m / q) is a very important parameter, which represents the ratio of the mass of an ion to its charge. The relationship between the mass-to-charge ratio and the flight time can be expressed by the following formula:

[0012]

[0013] Among them, (m / q) is the mass-to-charge ratio, (U) is the acceleration voltage, (t) is the flight time, (q) is the charge number of the ion, and L is the field-free flight length. According to this formula, it can be seen that there is a square root relationship between the mass-to-charge ratio and the flight time. When the acceleration voltage and the ion charge number are fixed, the mass-to-charge ratio is proportional to the flight time, that is, the longer the flight time, the larger the mass-to-charge ratio.

[0014] The dynamic range of a mass spectrometer refers to the ratio range between the minimum and maximum signal intensities that the mass spectrometer can detect. The dynamic range is usually expressed in decibels (dB), and the calculation formula is:

[0015] Dynamic range (dB) = 10 * log10 (maximum signal intensity / minimum detectable signal intensity).

[0016] In a mass spectrometer, the dynamic range is an important performance indicator, which determines the signal intensity range that the mass spectrometer can detect. A larger dynamic range means that the mass spectrometer can detect both strong and weak signals simultaneously, which is very important for analyzing complex samples. The dynamic range of common mass spectrometers generally does not exceed 5 orders of magnitude. Different types of mass spectrometers (such as time-of-flight mass spectrometers, quadrupole mass spectrometers, ion trap mass spectrometers, etc.) have different dynamic ranges, and the specific values will also vary depending on the instrument model and manufacturer. Generally speaking, the larger the dynamic range, the wider the application range of the mass spectrometer, and it can detect high-concentration signals without losing trace substance information.

[0017] In the actual application of mass spectrometers, especially for proton transfer mass spectrometry (PTR), the measurement range is from the lowest dozens of ppt to dozens of PPM, and the dynamic range requirement reaches 6 orders of magnitude or even 7 orders of magnitude.

[0018] For the vast majority of types of mass spectrometry, due to different responses, standard curves must be made first. And the standard curve needs to be redone every once in a while to achieve data quantification. The PTR quantification method can estimate the concentration of substances by using the proton transfer reaction equation, which is a characteristic that most mass spectrometry methods do not have. The Lindinger research group that proposed PTR-MS pointed out that when the k value of H3O + can be compared with that of the analyte, in most cases, the consistency between theory and experiment is better than 25%. Obtaining correct H3O + data is of great significance for subsequent data analysis and processing of PTR.

[0019] In actual PTR applications, in order to increase the probability of collision, the ion source needs to provide enough hydrated protons, and a very high H3O +Concentration. At this time, the instrument designer will adopt many methods, such as using the selective permeability of the quadrupole to block H3O + To pass through, or adding a pulsed voltage to the entire reflection area so that ions can pass through the holes below the reflection area, achieving a substantial reduction in the mass spectrometry peak with a relatively high concentration, so that the signal with a low concentration will not fail to respond due to the concentrated arrival of high-concentration ions at the MCP (microchannel plate). However, only using a pulse to allow high-concentration ions to pass through the lower part of the reflection area, according to the current electronic technology, for the reflection area using a pulsed voltage of more than 500V, the switch takes at least 40ns or even higher. This will cause high-concentration ions or ions around the ions that need to be finely measured for the mass-to-charge ratio to be lost due to the too long pulse time.

[0020] In more applications, when measuring substances with trace concentrations in the ppb or even ppt level, the mass spectrometry obtains data mostly by using the method of data accumulation. The commonly used time-of-flight analysis mass spectrometry basically needs to complete the data accumulation of more than 10K in 1S. In this way, the time resolution of the time-of-flight mass spectrometry is generally about 1ns, and it is difficult to simultaneously achieve a fine expansion of a very small mass-to-charge ratio range and a wide mass-to-charge ratio measurement range in the obtained spectrum. Summary of the Invention

[0021] To solve the above technical problems, the purpose of the present invention is to provide a dual time-of-flight mass spectrometer and a detection method, which can simultaneously achieve a wide mass-to-charge ratio measurement range and finely measure the signal of a certain mass-to-charge ratio through two-stage mass spectrometry analysis.

[0022] To achieve the above technical purpose and reach the above technical effect, the present invention is realized through the following technical solutions:

[0023] On the one hand, the present invention provides a dual time-of-flight mass spectrometer, including an ion generation and transmission area, a first time-of-flight mass spectrometry analysis area, a secondary ion transmission area, and a second time-of-flight mass spectrometry analysis area;

[0024] The ion generation and transmission area is used to generate ions to be measured and transmit the ions to be measured to the first time-of-flight mass spectrometry analysis area;

[0025] The first time-of-flight mass spectrometry analysis area is used to perform time-of-flight mass spectrometry analysis on the ions to be measured ejected from the ion generation and transmission area; the first time-of-flight mass spectrometry analysis area includes a first repulsion area, a first acceleration area, a first field-free flight area, a reflection area, and a first detector;

[0026] The secondary ion transmission area is arranged below the reflection area of the first time mass spectrometry analysis area and is used to transmit the ions to be measured passing through the reflection area of the first time-of-flight mass spectrometry analysis area to the second time-of-flight mass spectrometry analysis area;

[0027] The second time-of-flight mass spectrometry analysis area is used for performing refined time-of-flight mass spectrometry analysis on the ions to be measured that pass through the reflection area of the first time-of-flight mass spectrometry analysis area.

[0028] Further, the ion generation and transmission area includes a molecular ion reactor and an ion transmission system; the molecular ion reactor is used for causing a proton transfer reaction by colliding the initial reaction ions generated by the initial ion source with the sample molecules to be measured, so as to ionize the sample molecules to be measured and generate ions to be measured; the ion transmission system is used for transmitting the ions to be measured to the first time-of-flight mass spectrometry analysis area.

[0029] Further, the molecular ion reactor includes an initial ion source and a drift tube connected to the initial ion source; the front end of the initial ion source has an air inlet for introducing an initial reaction gas into the interior of the initial ion source; the initial ion source forms initial reaction ions through cathode discharge, and the initial reaction ions collide with the sample molecules to be measured in the drift tube to generate ions to be measured through a proton transfer reaction.

[0030] Further, the ion transmission system includes an extraction electrode 1, an extraction electrode 2, a first DC quadrupole located between the extraction electrode 1 and the extraction electrode 2, and a first single lens group.

[0031] Further, the first repulsion area is used for pushing the ions to be measured into the first acceleration area.

[0032] The first acceleration area is used for accelerating the ions to be measured so that the ions to be measured fly in the first field-free flight area.

[0033] The reflection area is used for reflecting the ions to be measured flying in the first field-free flight area to the first detector so that the first detector detects the ions to be measured.

[0034] Further, the first time-of-flight mass spectrometry analysis area includes a first repulsion plate and a first acceleration electric field; the first repulsion plate is used for repelling the ions to be measured into the first acceleration area formed by the first acceleration electric field.

[0035] Further, the reflection area is connected to a DC power supply and a pulse power supply, and the voltage of the pulse power supply is less than the voltage of the DC power supply.

[0036] Even further, the reflection area includes a reflection electrode and an electrode field located above the reflection electrode.

[0037] Further, the second ion transmission area includes an extraction electrode 3, an extraction electrode 4, a second DC quadrupole located between the extraction electrode 3 and the extraction electrode 4, and a second single lens group.

[0038] Further, the second time-of-flight mass spectrometry analysis region includes a secondary repulsion region, a secondary acceleration region, a secondary field-free flight region, and a secondary detector.

[0039] On the other hand, the present invention also provides a detection method, which is carried out by using the two-stage time-of-flight mass spectrometer described above, and includes the following steps:

[0040] The ion generation and transmission region generates ions to be measured and transmits the ions to be measured to the first time-of-flight mass spectrometry analysis region;

[0041] The first time-of-flight mass spectrometry analysis region performs time-of-flight mass spectrometry analysis on the ions to be measured ejected from the ion generation and transmission region;

[0042] The secondary ion transmission region transmits the ions to be measured passing through the reflection region of the first time mass spectrometry analysis region to the second time-of-flight mass spectrometry analysis region;

[0043] The second time-of-flight mass spectrometry analysis region performs refined time-of-flight mass spectrometry analysis on the ions to be measured passing through the reflection region of the first time-of-flight mass spectrometry analysis region.

[0044] The beneficial effects of the present invention are:

[0045] By providing a second time-of-flight mass spectrometry analysis region at the transmission position of the reflection region of the first time-of-flight mass spectrometry analysis region, the second time-of-flight mass spectrometry analysis region uses the ions passing through the reflection region of the first time-of-flight mass spectrometry analysis region as the ion source, so that the spectral peaks (referring to the time width of the spectral peaks) that appear in the time period when the ion arrival time difference at the MCP is 10 - 100 ns are extended to 10000 ns by the second time-of-flight mass spectrometry analysis region, thus realizing the fine collection of possible ion signals in a certain period.

[0046] In addition, the reflection region of the first time-of-flight mass spectrometry analysis region of the present invention is connected to a DC power supply and a pulse power supply, and a DC plus pulse scheme is adopted. The pulse amplitude is relatively low and can be controlled within dozens of volts. The switching time of the pulse can be greatly reduced, and it will not affect the measurement of other ions with different mass-to-charge ratios before and after when passing through high-concentration ions that are not needed. Moreover, since the DC part in the reflection region always exists, compared with the scheme that only uses pulses, some ions that need to pass through or be finely measured will be decelerated by the electric field formed by the DC voltage during the process of passing through, and the initial kinetic energy of the ions will be much lower than that when directly turning off the DC power supply with a pulse, which prepares for the next refined measurement.

[0047] The present invention not only ensures the simultaneity of measuring samples, can repel ions near a certain mass-to-charge ratio that are not needed with the least influence, and at the same time realizes a wide mass-to-charge ratio measurement range and fine measurement of signals in a selected mass-to-charge ratio range through two-stage mass spectrometry analysis. Description of the Drawings

[0048] Figure 1 It is a schematic structural diagram of a dual time-of-flight mass spectrometer according to an embodiment of the present invention.

[0049] In the figure, 1: Ion generation and transmission region, 101: Molecular ion reactor, 102: Extraction electrode 1, 103: Extraction electrode 2, 104: First DC quadrupole, 105: First single lens group, 106: Inlet; 2: First time-of-flight mass spectrometry analysis region, 21: First repulsion region, 210: First repulsion plate, 22: First acceleration region, 220: First metal electrode, 221: First grid electrode, 222: Second grid electrode; 23: First field-free flight region, 24: Reflection region, 240: Reflection electrode, 241: Second metal electrode, 242: Third grid electrode, 243: Fourth grid electrode, 244: DC power supply, 245: Pulse power supply, 25: First detector, 251: First microchannel plate, 252: First coupling capacitor; 3: Secondary ion transmission region, 301: Extraction electrode 3, 302: Extraction electrode 4, 303: Second DC quadrupole, 304: Second single lens group; 4: Second time-of-flight mass spectrometry analysis region, 41: Second repulsion region, 410: Second repulsion plate, 42: Second acceleration region, 420: Third metal electrode, 421: Fifth grid electrode, 422: Sixth grid electrode, 43: Second field-free flight region, 44: Second detector, 441: Second microchannel plate, 442: Second coupling capacitor; 5: Ions to be measured. Detailed implementation manners

[0050] The following elaborates on the preferred embodiments of the present invention in conjunction with the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making the protection scope of the present invention more clearly defined.

[0051] As Figure 1 shown in a preferred embodiment of a dual time-of-flight mass spectrometer, which includes an ion generation and transmission region 1, a first time-of-flight mass spectrometry analysis region 2, a secondary ion transmission region 3, and a second time-of-flight mass spectrometry analysis region 4;

[0052] The ion generation and transmission region 1 is used to generate ions to be measured 5 and transmit the ions to be measured 5 to the first time-of-flight mass spectrometry analysis region 2;

[0053] The first time-of-flight mass spectrometry analysis region 2 is used to perform time-of-flight mass spectrometry analysis on the ions to be measured ejected from the ion generation and transmission region 1; the first time-of-flight mass spectrometry analysis region 2 includes a first repulsion region 21, a first acceleration region 22, a first field-free flight region 23, a reflection region 24, and a first detector 25;

[0054] The secondary ion transmission region 3 is disposed below the reflection region 24 of the first time-of-flight mass spectrometry analysis region 2 for transmitting the ions to be measured that pass through the reflection region 24 of the first time-of-flight mass spectrometry analysis region 2 to the second time-of-flight mass spectrometry analysis region 4;

[0055] The second time-of-flight mass spectrometry analysis region 4 is used for performing time-of-flight mass spectrometry refinement analysis on the ions to be measured that pass through the reflection region 24 of the first time-of-flight mass spectrometry analysis region 2.

[0056] Specifically, the ion generation and transmission region 1 includes a molecular ion reactor 101 and an ion transmission system; the molecular ion reactor 101 is used for generating ions to be measured by proton transfer reaction through the collision of the initial reaction ions generated by the initial ion source with the sample molecules to be measured; the ion transmission system is used for transmitting the ions to be measured to the first time-of-flight mass spectrometry analysis region 2.

[0057] The molecular ion reactor 101 includes an initial ion source and a drift tube connected to the initial ion source; the front end of the initial ion source has an air inlet 106 for introducing an initial reaction gas into the interior of the initial ion source; in addition, a sample inlet (not shown in the figure) for introducing the sample molecules to be measured is provided on the drift tube; the initial ion source is used for ionizing the initial reaction gas introduced into its interior into initial reaction ions through cathode discharge, and the initial reaction ions collide with the sample molecules to be measured in the drift tube to generate proton transfer reaction to ionize the sample to be measured, thereby generating ions to be measured.

[0058] The ion transmission system includes an extraction electrode 102, an extraction electrode 103, a first DC quadrupole 104 located between the extraction electrode 102 and the extraction electrode 103, and a first single lens group 105. The ion transmission system is used for screening, focusing and transmitting the ions to be measured to the first time-of-flight mass spectrometry analysis region 2.

[0059] In the first time-of-flight mass spectrometry analysis region 2, the primary repulsion region 21 is used for pushing the ions to be measured into the primary acceleration region 22, the primary acceleration region 22 is used for accelerating the ions to be measured so that the ions to be measured fly in the primary field-free flight region 23, and the reflection region 24 is used for reflecting the ions to be measured flying in the primary field-free flight region 23 to the primary detector 25 so that the primary detector 25 detects the ions to be measured.

[0060] More specifically, the first time-of-flight mass spectrometry analysis region 2 includes a first repelling plate 210 and a first accelerating electric field; the first accelerating electric field includes a plurality of first metal electrodes 220 arranged in parallel, and a grid is provided on the first metal electrode 220 located in the upper part to form a first grid electrode 221 and a second grid electrode 222. The first repelling plate 210 is used to repel the ions to be measured into the first accelerating region formed by the first accelerating electric field.

[0061] The reflection region 24 is connected to a DC power supply 244 and a pulse power supply 245. Specifically, the reflection region 24 includes a reflection electrode 240 and an electrode field above the reflection electrode 240; more specifically, the electrode field includes a plurality of second metal electrodes 241 arranged in parallel, and grids are provided on two of the second metal electrodes 241 to form a third grid electrode 242 and a fourth grid electrode 243. The second metal electrode 241 is connected to the DC power supply 244 and the pulse power supply 245. The voltage of the pulse power supply is less than the voltage of the DC power supply.

[0062] The first detector 25 includes a first microchannel plate 251 and a first coupling capacitor 252.

[0063] The second ion transmission region 3 includes an extraction electrode three 301, an extraction electrode four 302, a second DC quadrupole 303 located between the extraction electrode three 301 and the extraction electrode four 302, and a second single lens group 304. The second ion transmission region 3 screens, focuses, and transmits the ions transmitted through the reflection electrode 240 of the first time-of-flight mass spectrometry analysis region 2 to the second time-of-flight mass spectrometry analysis region 4.

[0064] The second time-of-flight mass spectrometry analysis region 4 includes a second repelling region 41, a second accelerating region 42, a second field-free flight region 43, and a second detector 44. More specifically, the second time-of-flight mass spectrometry analysis region 4 includes a second repelling plate 410 and a second accelerating electric field; the second accelerating electric field includes a plurality of third metal electrodes 420 arranged in parallel, and a grid is provided on the third metal electrode 420 located in the upper part to form a fifth grid electrode 421 and a sixth grid electrode 422. The second repelling plate 410 is used to repel the ions transmitted through the reflection electrode 240 of the first time-of-flight mass spectrometry analysis region 2 into the second accelerating region 42 formed by the second accelerating electric field. The second detector 44 includes a second microchannel plate 441 and a second coupling capacitor 442.

[0065] Based on the detection method of the above-mentioned dual time-of-flight mass spectrometer, the following steps are included:

[0066] The ion generation and transmission region 1 generates ions to be measured and transmits the ions to be measured to the first time-of-flight mass spectrometry analysis region 2;

[0067] The first time-of-flight mass spectrometry analysis region 2 performs time-of-flight mass spectrometry analysis on the ions to be measured ejected from the ion generation and transmission region 1;

[0068] The secondary ion transmission region 3 transmits the ions to be measured transmitted through the reflection region 24 of the first time-of-flight mass spectrometry analysis region 2 to the second time-of-flight mass spectrometry analysis region 3;

[0069] The second time-of-flight mass spectrometry analysis region 3 performs time-of-flight mass spectrometry analysis and detection on the ions to be measured transmitted through the reflection region 24 of the first time-of-flight mass spectrometry analysis region 2 to obtain a mass spectrum of the ions to be measured.

[0070] This dual time-of-flight mass spectrometer can be applied to the real-time on-line detection of atmospheric trace volatile organic compounds (VOCs). Of course, the present invention is not limited thereto. In other embodiments, the mass spectrometer can also be applied to fields such as food detection.

[0071] Based on this dual time-of-flight mass spectrometer below, taking water vapor as the initial reaction gas and hydronium ion H3O + as an example, the detection and analysis process of the sample VOCs to be measured will be described.

[0072] Referring to Figure 1 , after the water vapor enters the interior of the initial ion source of the molecular ion reactor 101 from the air inlet 106, it is ionized into hydronium ion H3O + , the hydronium ion H3O + enters the interior of the drift tube, and the un-ionized water vapor and the like will be discharged from the air outlet (not shown in the figure) provided on the molecular ion reactor 101. The hydronium ion H3O +After entering the drift tube, it will collide with the sample molecules to be measured entering the drift tube from the sample inlet, causing a proton transfer reaction to ionize the sample molecules to be measured and generate ions to be measured. The ion generation and transmission region 1 screens, focuses, and transmits the ions to be measured to the first time-of-flight mass spectrometry analysis region 2; the first-stage repeller plate 210 in the first time-of-flight mass spectrometry analysis region 2 pushes the ions to be measured into the first-stage acceleration region 22, and the first-stage acceleration region 22 accelerates the ions to be measured so that the ions to be measured fly in the first-stage field-free flight region 23. The reflection region 24 reflects the ions to be measured to the first-stage detector 25, and the first-stage detector 25 detects the ions to be measured. Under the action of the pulse voltage and direct current in the reflection region 24, some ions pass through the holes below the reflection electrode 240; the second-stage ion transmission region 3 screens, focuses, and transmits the ions to be measured passing through the reflection region of the first time-of-flight mass spectrometry analysis region 2 to the second time-of-flight mass spectrometry analysis region 4; the second-stage repeller plate 410 in the second time-of-flight mass spectrometry analysis region 4 pushes the incoming ions to be measured into the second-stage acceleration region 42, and the second-stage acceleration region 42 accelerates the ions to be measured so that the ions to be measured fly in the second-stage field-free flight region 43. After reaching the second-stage detector 44, the second-stage detector 44 detects the ions to be measured to obtain a mass spectrum.

[0073] The basic principles of the first time-of-flight mass spectrometry analysis region and the second time-of-flight mass spectrometry analysis region are as follows: Ions with different mass-to-charge ratios are accelerated through the acceleration region. After obtaining the same kinetic energy, they enter a field-free flight region. Due to different mass-to-charge ratios, the ions obtain different flight speeds. Ions with a small mass-to-charge ratio have a fast speed, and ions with a large mass-to-charge ratio have a slow speed. Then, after flying a certain distance, they will reach the detector one after another for detection to obtain a spectrum.

[0074] Both the mass spectrometry dynamic range and the fineness can help the user determine the composition of the compound to be analyzed. The present invention adopts a method of combining two time-of-flight mass spectrometers to form a spectrum acquisition method that can not only achieve a large dynamic range but also display fine components:

[0075] 1. The first time-of-flight mass spectrometry analysis region obtains a spectrum with a large mass-to-charge ratio range.

[0076] 2. The second time-of-flight mass spectrometry analysis region obtains a spectrum in this mass-to-charge ratio range according to the spectrum range to be analyzed in the first time-of-flight mass spectrometry analysis region.

[0077] 3. According to the set conditions, the two spectra are correlated and provided to the user with a spectrum that can achieve large dynamic range measurement or fine measurement.

[0078] Finally, the superimposed spectral data is processed and analyzed to extract the required information or features.

[0079] This synthetic acquisition method can improve the dynamic range of the mass spectrometry spectrum, preventing weak signals from being overwhelmed by strong signals, thereby better analyzing and quantifying the components of the sample. At the same time, since a relatively small time range released in the first time-of-flight mass spectrometry analysis area is extended to a relatively long time range in the second time-of-flight mass spectrometry analysis area, more precise measurement of this time range (mass-to-charge ratio) can be achieved.

[0080] The above are only embodiments of the present invention and do not limit the patent scope of the present invention accordingly. Any equivalent structural or equivalent process transformation made using the content of the specification and drawings of the present invention, or direct or indirect application in other related technical fields, shall equally be included in the patent protection scope of the present invention.

Claims

1. A two-stage time-of-flight mass spectrometer, characterized in that, It includes an ion generation and transmission region, a first time-of-flight mass spectrometry analysis region, a secondary ion transmission region, and a second time-of-flight mass spectrometry analysis region; The ion generation and transmission region is used to generate ions to be measured and transmit the ions to be measured to the first time-of-flight mass spectrometry analysis region; The first time-of-flight mass spectrometry analysis region is used to perform time-of-flight mass spectrometry analysis on the ions to be measured ejected from the ion generation and transmission region; the first time-of-flight mass spectrometry analysis region includes a first repulsion region, a first acceleration region, a first field-free flight region, a reflection region, and a first detector; The secondary ion transmission region is arranged below the reflection region of the first time-of-flight mass spectrometry analysis region and is used to transmit the ions to be measured passing through the reflection region of the first time-of-flight mass spectrometry analysis region to the second time-of-flight mass spectrometry analysis region; The second time-of-flight mass spectrometry analysis region is used to perform refined time-of-flight mass spectrometry analysis on the ions to be measured passing through the reflection region of the first time-of-flight mass spectrometry analysis region.

2. The two-stage time-of-flight mass spectrometer according to claim 1, characterized in that The ion generation and transmission region includes a molecular ion reactor and an ion transmission system; the molecular ion reactor is used to make the initial reaction ions generated by the initial ion source collide with the sample molecules to be measured to undergo a proton transfer reaction to ionize the sample molecules to be measured and generate ions to be measured; the ion transmission system is used to transmit the ions to be measured to the first time-of-flight mass spectrometry analysis region.

3. A two-stage time-of-flight mass spectrometer according to claim 2, wherein, The molecular ion reactor includes an initial ion source and a drift tube connected to the initial ion source; the front end of the initial ion source has an air inlet for introducing an initial reaction gas into the interior of the initial ion source; the initial ion source is used to ionize the initial reaction gas introduced into its interior into initial reaction ions, and the initial reaction ions collide with the sample molecules to be measured in the drift tube to undergo a proton transfer reaction to generate ions to be measured.

4. A two-stage time-of-flight mass spectrometer according to claim 2, characterized in that The ion transmission system includes a first extraction electrode, a second extraction electrode, a first DC quadrupole located between the first extraction electrode and the second extraction electrode, and a first single lens group.

5. A two-stage time-of-flight mass spectrometer according to claim 1, characterized in that, The first repulsion region is used to push the ions to be measured into the first acceleration region; The first acceleration region is used to accelerate the ions to be measured so that the ions to be measured fly in the first field-free flight region; The reflection region is used to reflect the ions to be measured flying in the first field-free flight region to the first detector so that the first detector detects the ions to be measured.

6. A dual time-of-flight mass spectrometer according to claim 1 or 5, characterized in that, The first time-of-flight mass spectrometry analysis region includes a first repulsion plate and a first acceleration electric field; the first repulsion plate is used to repel the ions to be measured into the first acceleration region formed by the first acceleration electric field.

7. A dual time-of-flight mass spectrometer according to claim 1, characterized in that, The reflection region is connected to a DC power supply and a pulse power supply, and the voltage of the pulse power supply is less than the voltage of the DC power supply.

8. A two-stage time-of-flight mass spectrometer according to claim 1, characterized in that, The secondary ion transmission region includes a third extraction electrode, a fourth extraction electrode, a second DC quadrupole located between the third extraction electrode and the fourth extraction electrode, and a second single lens group.

9. A two-stage time-of-flight mass spectrometer according to claim 1, characterized in that, The second time-of-flight mass spectrometry analysis region includes a second repulsion region, a second acceleration region, a second field-free flight region, and a second detector.

10. A detection method, characterized in that, It is carried out by using the two-stage time-of-flight mass spectrometer according to any one of claims 1 to 9, and includes the following steps: The ion generation and transmission region generates ions to be measured and transmits the ions to be measured to the first time-of-flight mass spectrometry analysis region; The first time-of-flight mass spectrometry analysis area performs time-of-flight mass spectrometry analysis on the ions to be measured ejected from the ion generation and transmission area; The secondary ion transmission area transmits the ions to be measured passing through the reflection area of the first time mass spectrometry analysis area to the second time-of-flight mass spectrometry analysis area; The second time-of-flight mass spectrometry analysis area performs refined time-of-flight mass spectrometry analysis on the ions to be measured passing through the reflection area of the first time-of-flight mass spectrometry analysis area.

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