CN111029242A - Ion signal detection device and method for quadrupole rod mass analyzer - Google Patents
Ion signal detection device and method for quadrupole rod mass analyzer Download PDFInfo
- Publication number
- CN111029242A CN111029242A CN201911323869.9A CN201911323869A CN111029242A CN 111029242 A CN111029242 A CN 111029242A CN 201911323869 A CN201911323869 A CN 201911323869A CN 111029242 A CN111029242 A CN 111029242A
- Authority
- CN
- China
- Prior art keywords
- ion
- electrodes
- ions
- quadrupole
- mass analyzer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
- H01J49/02—Details
- H01J49/025—Detectors specially adapted to particle spectrometers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
- G01N27/622—Ion mobility spectrometry
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
- H01J49/0027—Methods for using particle spectrometers
- H01J49/0031—Step by step routines describing the use of the apparatus
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
- H01J49/26—Mass spectrometers or separator tubes
- H01J49/34—Dynamic spectrometers
- H01J49/42—Stability-of-path spectrometers, e.g. monopole, quadrupole, multipole, farvitrons
- H01J49/4205—Device types
- H01J49/422—Two-dimensional RF ion traps
- H01J49/4225—Multipole linear ion traps, e.g. quadrupoles, hexapoles
Abstract
The invention discloses an ion signal detection device and method for a quadrupole rod mass analyzer. The device comprises a quadrupole mass analyzer, an ion accelerating electrode and a working power supply thereof, and a current or voltage measuring device. According to the invention, an ion accelerating electrode comprising more than 2 electrodes is arranged behind a quadrupole rod, ions can rapidly move between the electrodes under the action of voltage by loading voltage on the electrodes to generate a current signal corresponding to the movement of the ions, and then the current or voltage measuring device is used for measuring a related current signal generated by the movement of the ions between the electrodes to obtain a mass spectrum signal of the ions. The invention can obtain ion mass spectrum signals by measuring the current generated by the movement of ions; ion quantity information can be obtained based on the ion current, and then quantitative analysis is carried out; the invention does not use an electron multiplier, can avoid instrument faults caused by damage or aging of the electron multiplier, and avoids the problems of possible mass discrimination effect, ion signal saturation and the like of ions with different sizes.
Description
Technical Field
The invention relates to the technical field of mass spectrometry instruments, in particular to an ion signal detection device and method for a quadrupole rod mass analyzer.
Background
Mass spectrometers can analyze the composition of substances at the molecular level, including the various chemical components and their contents in a sample of the substance being analyzed, as well as the chemical structure of certain molecules, etc. using mass spectrometers. Due to the wide applicability of mass spectrometry and the advantages of rapidness, accuracy, high sensitivity and the like of mass spectrometry, the mass spectrometry becomes an indispensable analysis method in many fields such as chemistry, life science, material science, environmental monitoring, food safety, homeland safety and the like, and is one of the main scientific methods for human to know the world and transform the world. The basic working principle of the quadrupole mass analyzer is as follows: the sample species to be detected is ionized into ions using a suitable ion source and the sample ions are then introduced into a quadrupole mass analyzer via an ion optical system. According to the quadrupole mass spectrometry theory established by Paul inventor of quadrupole mass spectrometry, a quadrupole mass analyzer is composed of four cylindrical electrodes with hyperboloid cross sections, as shown in fig. 1, two symmetrical electrode rods are connected together by electric wires in use, and radio frequency working power supplies are loaded respectively. The quadrupole rod electrode system generates electric field distribution mainly based on a quadrupole electric field under the action of a radio frequency power supply, and when ions with different mass-to-charge ratios enter the quadrupole rod electrode system, the ions with specific mass-to-charge ratios can stably pass through the quadrupole rod electrode system under the action of the electric field distribution generated corresponding to certain alternating current and direct current voltages and penetrate through the ion leading-out small hole arranged on the rear end electrode to reach the ion detector to be detected. If the direct current voltage and the alternating current voltage of the radio frequency power supply are linearly scanned, if the direct current voltage and the alternating current voltage are linearly increased from small to large, ions with different mass-to-charge ratios pass through the quadrupole rod electrode system from small to large and finally reach the ion detector to be detected, and ion current/voltage signals corresponding to different voltages are recorded, so that a mass spectrogram of a sample to be analyzed is obtained, and chemical composition information of the sample to be analyzed is obtained. Briefly, a quadrupole mass spectrometry system consists of three major components, namely, (1) an ion source that turns a sample into ions, (2) a quadrupole mass analyzer that can distinguish the mass-to-charge ratios of the ions, and (3) an electron multiplier that can detect the ions.
The electron multiplier, also commonly referred to as an ion detector, will be referred to as "electron multiplier" hereinafter for convenience of description. It is constructed of a material with high secondary electron emission capability, and fig. 3 is a schematic diagram of an electron multiplier. In use, a high voltage operating power supply is applied between the two ends of the electron multiplier, thereby creating an electric field within the electron multiplier. When ions separated by a quadrupole mass analyzer impact the surface of an electron multiplier under the influence of an electric field, a plurality of secondary electrons will be generated. These secondary electrons will be accelerated and hit the surface of the multiplier at high speed under the action of the electric field generated by the operating voltage of the electron multiplier, generating more secondary electrons. This is repeated, and the electrons are accelerated again and again in the multiplier, producing more and more secondary electrons. Finally, all secondary electrons pass through the final electron exit of the electron multiplier and are collected by electrodes arranged behind the electron multiplier, obtaining current signals corresponding to the incident ions, which can also be converted into voltage signals, eventually becoming mass spectra signals.
It is clear that the electron multiplier is one of the essential major components of all current quadrupole mass spectrometry, including triple quadrupole mass spectrometry consisting of three quadrupole electrode systems, which is responsible for the task of quadrupole mass spectrometers to record ion signals and obtain mass spectra.
Suppose that the electron multiplication factor of an electron multiplier is 107Multiple multiplication, i.e. the number of secondary electrons generated by an ion gives a total number of 10 electrons7The final measured electron charge is then:
1.6×10-19×107＝1.6×10-12coulombs. (1)
If 1000 ions of the same mass-to-charge ratio enter the ion detector at the same time per second, the resulting electron charge should theoretically be:
1000×1.6×10-19×107＝1.6×10-9coulombs. (2)
The current generated is:
1000×1.6×10-19×107/1＝1.6×10-9in amperes.
If this current is converted into a voltage, it is assumed that the resistance used is 10 kilo-ohms, i.e. 10 x 103Ohm, then the voltage that can be measured is: v10 × 103×1.6×10-9＝1.6×10-5In volts.
The electron multipliers used at present have several major problems: (1) all electron multipliers are aged due to aging of materials, and the consequence is that the electron multiplication efficiency is poorer and poorer, so that the obtained mass spectrum signals are weaker and weaker; therefore, all electron multipliers have a certain service life; (2) different electron multiplier manufacturers, electron multipliers manufactured in different batches may have different final electron multiplication efficiencies due to different used materials or processes, and thus when used as a signal for detecting ions, may cause mass spectrum signals with equal ion content to have different magnitudes; (3) theoretically, the total amount of all secondary electrons generated by N ions should be equal to N times of that of one ion, but the secondary electron emission capability of all materials is limited, for example, a large number of electrons collide with the surface of a very small area of an electron multiplier in a very short time, and the number of generated secondary electrons is difficult to be a simple multiple of that generated by one electron, so that the so-called ion signal "saturation" phenomenon is caused, and the quantitative analysis result is inaccurate. (4) The electron multiplier also often has a mass discrimination effect, that is, one ion with a large mass-to-charge ratio and a large volume is small compared with one ion with a small mass-to-charge ratio, and the number of secondary electrons generated by the small ion is different, which finally causes the difference in the intensity of mass spectrum signals generated by the same number of large ions and small ions, resulting in the inaccuracy of the quantitative analysis result. (5) The electron multiplier is a consumable in a quadrupole mass spectrum vacuum chamber, and is expensive and inconvenient to replace.
Disclosure of Invention
In order to solve the defects in the existing ion detection technology, the invention provides a novel ion detection device and a novel ion detection method. The device has simple structure and low cost, and realizes the high-sensitivity test of the ion mass spectrum signal.
The invention sets an ion accelerating electrode comprising at least 2 electrodes at an ion leading-out end of the quadrupole mass analyzer, so that ions separated by the quadrupole mass analyzer are accelerated and move at high speed between the electrodes, and further, an ion mass spectrum signal is obtained by measuring current generated by the movement of the ions between the electrodes.
The basic idea of the invention is that:
assuming that the ions separated by the quadrupole mass analyzer are accelerated to 3000eV, the time taken for the ions to pass through the two ion current detecting electrodes at high speed is 10-8Second (i.e., 10 nanoseconds), the current produced is:
if 1000 ions with the same mass-to-charge ratio enter the ion current detection device at the same time, the final given electron current should theoretically be:
if this current is converted into a voltage, it is assumed that the resistance used is 10 kilo-ohms, i.e. 10 x 103Ohm, then the voltage that can be measured is: v10 × 103×1.6×10-8＝1.6×10-4In volts.
The technical scheme of the invention is specifically introduced as follows.
An ion signal detection device for a quadrupole mass analyser comprises a quadrupole mass analyser, an ion accelerating electrode and a working power supply thereof, and a current or voltage measuring device; the ion accelerating electrode comprises at least 2 electrodes which are mutually electrically insulated, the ion accelerating electrode is arranged at an ion leading-out end of the quadrupole mass analyzer, small holes are correspondingly arranged on other electrodes close to the quadrupole mass analyzer except the farthest electrode according to the sequence from near to far, the working power supply is connected with the 2 electrodes closest to the quadrupole mass analyzer, and the current or voltage measuring device is connected with the 2 electrodes farthest from the quadrupole mass analyzer.
In the invention, the quadrupole mass analyzer is a single mass analyzer composed of four columnar electrodes or composed of a plurality of groups of four columnar electrodes connected in series; or a combination of a mass analyser made up of four cylindrical electrodes and other mass analysers. When the quadrupole mass analyzer is in series connection or is combined with other different mass analyzers, the ion accelerating electrodes are arranged at the ion leading-out ends of the four cylindrical electrodes in the last group.
The invention also provides a detection method of the ion signal detection device for the quadrupole rod mass analyzer, which comprises the following specific steps: and applying voltage to 2 electrodes closest to the quadrupole mass analyzer in the ion accelerating electrodes through a working power supply, so that the ions separated from the quadrupole mass analyzer directionally move to the electrode of the ion accelerating electrode farthest from the quadrupole mass analyzer to form current, and testing the current or the voltage on the 2 electrodes closest to the quadrupole mass analyzer through a device for measuring the current or the voltage to obtain a mass spectrum signal.
Compared with the prior art, the invention has the advantages that:
(1) the device has simple structure, low cost, long service life and high test precision and sensitivity;
(2) the invention measures the current signal generated by the movement of ions, so that the problem of unequal multiplication efficiency of ions with different sizes is avoided, and the test result is stable.
(3) Theoretically, the current generated by N ions is strictly equal to N times of the current generated by one ion, so that the phenomenon of signal saturation is avoided, and the mass discrimination effect is avoided, namely the mass spectrum signal intensity generated by the same number of large ions and small ions is completely the same, and the quantitative analysis result is accurate.
Drawings
Fig. 1 is a schematic diagram of a quadrupole mass analyzer.
Fig. 2 is a schematic diagram of a conventional electrospray ionization quadrupole mass spectrometer.
Fig. 3 is a schematic diagram of the operation of the electron multiplier.
Figure 4 is a schematic diagram of an electrospray ionization-quadrupole mass analyzer-ion signal detection system instrument system constructed in accordance with the teachings of the present invention.
Figure 5 is a schematic diagram of an electrospray ionization-triple quadrupole mass analyzer-ion signal detection system instrument system constructed in accordance with the teachings of the present invention.
Detailed Description
The present invention will be described in further detail below with reference to the accompanying drawings, but the present invention is not limited thereto.
Fig. 1 is a schematic diagram of a quadrupole mass analyzer. In fig. 1, 11, 12, 13 and 14 are four electrodes fixed in a certain way, in practical application, 11 and 13 are connected together and loaded with a radio frequency power source RF, 12 and 14 are connected together and loaded with a negative electrode-RF of the same radio frequency power source, the quadrupole electrode system will generate electric field distribution with quadrupole electric field as the main under the action of the radio frequency power source RF, when ions with different mass-to-charge ratios enter the quadrupole electrode system, under the action of the electric field distribution generated corresponding to certain alternating current and direct current voltages, ions with specific mass-to-charge ratios can stably pass through the quadrupole electrode system. If the direct current voltage and the alternating current voltage of the radio frequency power supply are linearly scanned, if the direct current voltage and the alternating current voltage are linearly increased from small to large, ions with different mass-to-charge ratios pass through the quadrupole rod electrode system from small to large, and finally reach the ion detector to be detected.
In fig. 2, 21 is the sample ions generated by the ion source, 22 is the electrode between the ion source and the ion guide 23, and the ions can pass through the aperture in 22 into 23 and be transported to the next section; 24 are electrodes between the ion guide 23 and a quadrupole ion mass analyser 25, and ions can pass through apertures in 24 into 25. A quadrupole ion mass analyser 25 is applied with a radio frequency voltage which produces a quadrupole electric field in the quadrupole ion mass analyser system, and ions of a particular mass to charge ratio can be stabilised across the quadrupole electrode system and detected by passing through an ion extraction aperture 26 mounted in the back end 27 electrode to an ion detector 29, while varying the dc and ac component magnitudes and proportions in the radio frequency voltage. A voltage may be applied to the electrodes 28 to create an electric field that deflects the ions. If the direct current voltage and the alternating current voltage of the radio frequency power supply are linearly scanned, if the direct current voltage and the alternating current voltage are linearly increased from small to large, ions with different mass-to-charge ratios pass through the quadrupole rod electrode system from small to large and finally reach the ion detector 29 to be detected, and ion current/voltage signals corresponding to different voltages are recorded, so that a mass spectrogram of a sample to be analyzed is obtained, and chemical composition information of the sample to be analyzed is obtained. Briefly, a quadrupole mass spectrometry system consists of three major components, namely, (1) an ion source 21 that turns the sample into ions, (2) a quadrupole mass analyzer 25 that can distinguish the mass-to-charge ratios of the ions, and (3) an electron multiplier 29 that can detect the ions.
Fig. 3 is a schematic diagram of the operation of the electron multiplier. In fig. 3, 31 is a sample ion generated by an ion source, and when the ion 31 with certain energy is collided with the surface 32 of an electron multiplier which is made of a material with secondary electron emission capability, secondary electrons 33 and 34 are generated, and 33 and 34 are collided with the surfaces 35 and 36 of the electron multiplier under the action of the working voltage of the electron multiplier, and 351 and 352 are generated by 33, and 361 and 362 are generated by 34. The secondary electrons generated by each collision will continue to hit the surface generating more and more secondary electrons up to the exit 300 of the electron multiplier. The electron current signal generated by the multiple multiplications is collected and measured 31, i.e. a mass spectral signal associated with the ions 31 is obtained.
Figure 4 is a schematic diagram of an electrospray ionization-quadrupole mass analyzer-ion signal detection system instrument system constructed in accordance with the teachings of the present invention. In fig. 4, 41 is the sample ions generated by the ion source, 42 is the electrode between the ion source and the ion guide 43, and the ions can pass through the aperture in 42 into 43 and be transported to the next section; 44 is an electrode between the ion guide 43 and a quadrupole ion mass analyser 45, and ions can pass through apertures in 44 into 45. A radio frequency voltage that can generate a quadrupole electric field in a quadrupole ion mass analyzer system is applied to the quadrupole ion mass analyzer 45, and ions having a specific mass-to-charge ratio can stably pass through the quadrupole electrode system and pass through the ion extraction aperture 46 mounted on the back end electrode 47 while varying the size and ratio of the dc and ac components in the radio frequency voltage. The ion signal detection mode is different from the ion signal detection mode of the quadrupole mass spectrum which is commonly used at present: the quadrupole mass spectrometry system does not require the use of an electron multiplier to detect the ion signal, but rather performs the ion signal measurement in such a manner that after the 45 mass analyzed ion beam 50 passes through 46, it will be accelerated by the voltage applied between electrode 47 and electrode 48, and the accelerated ions will rapidly pass through the space between electrodes 48 and 49. Between the electrodes 48 and 49 there will be provided means for measuring the associated current signal generated by the rapid movement of the ions, i.e. the mass spectral signal of the ions. The size can be obtained from the previous analysis, i.e., equations (3) and (4).
It is clear that in the quadrupole mass spectrometry presented in the present invention, no electron multiplier is required for ion signal detection.
Figure 5 is a schematic diagram of an electrospray ionization-triple quadrupole mass analyzer-ion signal detection system instrument system constructed in accordance with the teachings of the present invention. The working process is that 51 is sample ions generated by an ion source, 52 is an ion transmission system, 53 is a first-stage quadrupole mass analyzer system for ion mass selection, and ions with certain mass-to-charge ratio can be selected according to the research work requirement. 54 is an ion collision dissociation quadrupole rod system, and mass-selected ions will collide with neutral atoms, such as helium, or argon atoms, at 54 to produce a variety of fragment ions. The fragment ions will be mass analysed by the third stage quadrupole mass analysis system 55 and the ions analysed by the third stage quadrupole mass analysis system 55 will pass through the aperture 57 in the middle of the electrode 56 in turn. When the mass analyzed ion beam passes through the aperture 57, it will be accelerated by the voltage applied between the electrodes 58 and 59, and the accelerated ions will rapidly pass through the space between the electrodes 59 and 60. Between the electrodes 59 and 60 there will be provided means 61 for measuring the associated current signal generated by the rapid movement of the ions, i.e. the mass spectral signal of the ions. The size can be obtained from the previous analysis, i.e., equations (3) and (4).
It is clear that in the triple quadrupole mass spectrometry presented in the present invention, there is no need to employ an electron multiplier for ion signal detection.
Claims (3)
1. An ion signal detection device for a quadrupole mass analyser, comprising a quadrupole mass spectrometer
Analyzer, ion accelerating electrode and its working power supply, and current or voltage measuring device; the ion accelerating electrode comprises at least 2 electrodes which are mutually electrically insulated, the ion accelerating electrode is arranged at an ion leading-out end of the quadrupole mass analyzer, small holes are correspondingly arranged on other electrodes close to the quadrupole mass analyzer except the farthest electrode according to the sequence from near to far, the working power supply is connected with the 2 electrodes closest to the quadrupole mass analyzer, and the current or voltage measuring device is connected with the 2 electrodes farthest from the quadrupole mass analyzer.
2. The ion signal detection apparatus of claim 1, wherein the mass spectrometer comprises a mass spectrometer,
the quadrupole rod mass analyzer is a single mass analyzer composed of four columnar electrodes or composed of a plurality of groups of four columnar electrodes connected in series; or a combination of a mass analyser made up of four cylindrical electrodes and other mass analysers.
3. A detection method of an ion signal detection device for a quadrupole mass analyzer according to claim 1, wherein a voltage is applied to 2 electrodes closest to the quadrupole mass analyzer among the ion accelerating electrodes through the working power supply, so that ions separated from the quadrupole mass analyzer directionally move to the electrode of the ion accelerating electrode farthest from the quadrupole mass analyzer to form a current, and the current or the voltage on the 2 electrodes closest to the quadrupole mass analyzer is tested through the current or voltage measuring device to obtain the mass spectrum signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911323869.9A CN111029242A (en) | 2019-12-20 | 2019-12-20 | Ion signal detection device and method for quadrupole rod mass analyzer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911323869.9A CN111029242A (en) | 2019-12-20 | 2019-12-20 | Ion signal detection device and method for quadrupole rod mass analyzer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111029242A true CN111029242A (en) | 2020-04-17 |
Family
ID=70211765
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911323869.9A Pending CN111029242A (en) | 2019-12-20 | 2019-12-20 | Ion signal detection device and method for quadrupole rod mass analyzer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111029242A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113675071A (en) * | 2020-05-14 | 2021-11-19 | 东华理工大学 | Preparation device of high-purity chemical substance |
-
2019
- 2019-12-20 CN CN201911323869.9A patent/CN111029242A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113675071A (en) * | 2020-05-14 | 2021-11-19 | 东华理工大学 | Preparation device of high-purity chemical substance |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6452168B1 (en) | Apparatus and methods for continuous beam fourier transform mass spectrometry | |
| US6107623A (en) | Methods and apparatus for tandem mass spectrometry | |
| JP3219434B2 (en) | Tandem mass spectrometry system | |
| US8637816B1 (en) | Systems and methods for MS-MS-analysis | |
| JP6305543B2 (en) | Targeted mass spectrometry | |
| US9627190B2 (en) | Energy resolved time-of-flight mass spectrometry | |
| JP5530531B2 (en) | Mass spectrometer and mass spectrometry method | |
| US4105917A (en) | Method and apparatus for mass spectrometric analysis at ultra-low pressures | |
| CN105355537B (en) | Ion trap low mass cut-off value cascade mass spectrometry method | |
| US9202676B2 (en) | Method and system for quantitative and qualitative analysis using mass spectrometry | |
| EP3309817A1 (en) | Imr-ms device | |
| CN111029242A (en) | Ion signal detection device and method for quadrupole rod mass analyzer | |
| US6365893B1 (en) | Internal calibration of time to mass conversion in time-of-flight mass spectrometry | |
| CN210897193U (en) | Ion signal detection device for quadrupole rod mass analyzer | |
| CN108918645B (en) | Isomeride body spectrum obtaining method and isomeride identification method | |
| US20210287892A1 (en) | Dynamic ion filtering for reducing highly abundant ions | |
| CN210897195U (en) | Ion signal detection device for ion trap mass spectrometer | |
| CN114430855B (en) | Automatic standardized spectrometer | |
| JP4644506B2 (en) | Mass spectrometer | |
| WO2000049640A1 (en) | Isotopomer mass spectrometer | |
| Zhang et al. | Instrumentation and methods for ion and reaction monitoring using a non-scanning rectilinear ion trap | |
| Medhe | Mass Spectrometry: Analysers an Important Tool | |
| CN110931341A (en) | Ion signal detection device and method for ion trap mass spectrometer | |
| CN210897194U (en) | Ion signal detection device for time-of-flight mass spectrometer | |
| CN110854009A (en) | Mass spectrum device of wide-range mass measurement ion source and mass spectrum method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |