An ion source

Abstract

Provided herein is an ion source comprising a plurality of components, at least one of which is partially coated with a layer of silicon. The ion source reduces reactivity between a sample and a carrier gas, reduces or eliminates tailing in an ion chromatogram, and / or improves mass spectrometric fidelity. Also provided are methods of using the ion source in a mass spectrometer or a gas chromatograph mass spectrometer.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Patent Application Serial No. 16 / 830,577, filed March 26, 2020. The entire contents of this application are incorporated herein by reference. Background Technology

[0003] When hydrogen is present as a carrier gas, or when helium is present as a carrier gas and hydrogen is added to the source as a cleaning agent, chromatographic peak distortion and mass spectrometry distortion will occur.

[0004] Unwanted interactions between analyte molecules and ions and hydrogen and substances in the mass spectrometer ionization source lead to problems such as mass spectrometry variations and chromatographic peak distortion (tailing). These problems are particularly severe for analytes with functional groups or chemical bonds that can be reduced in the presence of hydrogen. In some cases, the major ion of the analyte may exhibit no tailing, but the total ion chromatogram (TIC) will show significant tailing due to degradation products formed by the reaction of hydrogen with the compound.

[0005] Mass spectrometry distortion can be a serious problem. For some compounds, the variation between the spectrum and the spectrum of the reference library used for identification (e.g., the National Institute of Standards and Technology (NIST) mass spectrometry database) can be so large that the analyte is incorrectly identified as a different compound.

[0006] Therefore, there remains an unmet need for ion sources that exhibit spectral fidelity when used with hydrogen. This disclosure provides a solution to this need. Summary of the Invention

[0007] In one aspect, an ion source is provided, the ion source including a sample inlet and a plurality of components having surfaces and forming ion flow paths, wherein the surface of at least one of the plurality of components forming the ion flow paths is at least partially coated with a layer of silicon (Si), silicon hydride (SiH), or a combination thereof.

[0008] On the other hand, a method for analyzing a sample using a mass spectrometer includes using an ion source described herein. The method includes flowing a sample through a sample inlet in a carrier gas, ionizing the sample by at least one of a plurality of components forming an ion flow path to provide ions, and analyzing the ions based on their mass.

[0009] On the other hand, an ion source is provided, comprising a source chamber, a pull-out electrode post, a pull-out electrode plate, an inlet lens, an ion focusing lens, a repulsion electrode, a repulsion electrode block insert, an extraction lens, at least one post-extraction lens, or a combination thereof, wherein at least one of the source chamber, pull-out electrode post, pull-out electrode plate, inlet lens, ion focusing lens, repulsion electrode, repulsion electrode block insert, extraction lens, or at least one post-extraction lens is at least partially coated with a silicon layer.

[0010] On the other hand, mass spectrometry distortion or peak aberration is a persistent problem when using gas chromatography / mass spectrometry with hydrogen as the carrier gas or as a cleaning agent added to the source when helium is used as the carrier gas. Advantageously, in some cases, the ion sources described herein improve the performance of readily hydrogenated compounds such as nitrobenzene and 3-nitroaniline, resulting in higher spectral matching values ​​and more accurate identification when searching against a reference spectral library. For some compounds such as nitrobenzene, the EIC of their major ions exhibits varying degrees of tailing, making integration and identification via qualitative ion ratios challenging. Advantageously, in some cases, the ion sources described herein reduce or eliminate tailing in both the total ion chromatogram (TIC) and the extracted ion chromatogram (EIC).

[0011] Additional features and advantages of various embodiments will be set forth in part in the description which follows, and will be apparent in part from the description, or may be learned by practice of the various embodiments. The objects and other advantages of the various embodiments will be realized and obtained by means of the elements and combinations particularly pointed out in the description herein. Attached Figure Description

[0012] The accompanying drawings illustrate various examples of this application by way of example rather than limitation.

[0013] Figure 1 A cross-section of an ion source with a 9 mm hole in a pull-out electrode is shown, according to some examples.

[0014] Figure 2 The diagram shows the breakdown of ion sources based on some examples;

[0015] Figure 3 The diagram shows the breakdown of ion sources based on some examples;

[0016] Figure 4 The diagram shows the breakdown of ion sources based on some examples;

[0017] Figures 5A to 5DThis illustrates the issues related to the hydrogenation of nitrobenzene in a hydrogen support. Figure 5A shows the reference Coulomb spectrum of nitrobenzene from NIST17. Figure 5B shows the mass spectrum of nitrobenzene with hydrogen carrier gas using a 3 mm pull-out plate. Figure 5C shows the hydrogenation reaction of nitrobenzene. Figure 5D shows the extracted ion chromatograms (EIC) of ions 77, 93, and 123. According to some examples, the 93 EIC has severe tailing;

[0018] Figure 6 The EIC values ​​of nitrobenzene peaks were compared based on several examples;

[0019] Figures 7A to 7B The chromatograms of the n-alkane sample run are shown. Figure 7A shows the n-C ions run using the ion source of the present invention, along with those from previous attempts 1 and 2. 10 Zhizheng Structure C 40 Chromatogram of the sample. These signals are the response at mass 57, normalized to normal C. 13 The height of the peaks helps in comparison. Figure 7B shows the normal C according to some examples. 28 To the positive structure C 31 Development diagram of alkanes;

[0020] Figure 8 The total ion chromatograms of the insecticide etofenprox obtained according to some examples using the ion source of the present invention, as well as in previous attempts 1 and 2, are shown; and

[0021] Figure 9 The spectra of benzo[ghi]pyrene obtained using the ion source of the present invention, according to some examples, are shown.

[0022] Throughout the accompanying drawings, the same part numbers indicate the same or similar parts. Detailed Implementation

[0023] Reference will now be made to certain examples of the disclosed subject matter, which are partially illustrated in the accompanying drawings. Although the disclosed subject matter will be described in conjunction with the listed claims, it will be understood that the illustrative subject matter is not intended to limit the claims to the disclosed subject matter.

[0024] In this document, values ​​expressed in range format should be interpreted flexibly, including not only the numerical values ​​explicitly indicated as range limits, but also all individual numerical values ​​or subranges included within that range, as if each numerical value and subrange were explicitly indicated. For example, a range of “about 0.1% to about 5%” or “about 0.1% to 5%” should be interpreted as including not only about 0.1% to about 5%, but also the individual values ​​(e.g., 1%, 2%, 3%, and 4%) and subranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the specified range. The statement “about X to Y” has the same meaning as “about X to about Y” unless otherwise stated. Similarly, the statement “about X, Y, or about Z” has the same meaning as “about X, about Y, or about Z” unless otherwise stated.

[0025] In this document, the terms “a,” “an,” or “the” are used to include one or more unless the context clearly specifies otherwise. Unless otherwise stated, the term “or” is used to mean a non-exclusive “or.” Statements such as “at least one of A and B” or “at least one of A or B” have the same meaning as “A, B, or A and B.” Furthermore, it should be understood that the wording or terms used herein, unless otherwise defined, are for descriptive purposes only and not for limitation. The use of any section headings is to aid reading the document and is not to be construed as limiting; information relating to a section heading may appear within or outside that particular section. All publications, patents, and patent documents mentioned herein are incorporated herein in their entirety by reference as if they were individually incorporated by reference.

[0026] In the methods described herein, actions can be performed in any order, except when a time or sequence of operations is explicitly specified. Furthermore, specific actions can be performed simultaneously unless explicitly stated in the language that they are performed separately. For example, the required action to perform X and the required action to perform Y can be performed simultaneously in a single operation, and the resulting procedure will fall within the literal scope of the required procedure.

[0027] definition

[0028] The term “about” as used herein may allow for a degree of variability in a value or range, such as variability within 10%, 5%, or 1% of the limits of the value or range, and includes the exact value or range.

[0029] As used herein, the term “substantially” means the majority or most, such as at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or 100%.

[0030] As used herein, the term "internal surface" refers to a surface within any chamber (such as an ionization chamber, other enclosed space, or component) capable of undergoing undesirable interactions with the analyte. The term also includes surfaces of components that may not be part of a chamber but are located within it and capable of undergoing undesirable interactions with the analyte (such as devices for sample introduction, repulsion electrodes, extraction lenses, pull-out plates, etc.).

[0031] As used herein, “outer surface” refers to a portion of the surface of a component that is at least partially exposed to the atmosphere or environment when the ion source described herein is in operation. The outer surface may be coated with silicon, but such coating does not contribute to improving the spectral fidelity described herein.

[0032] The term "ionization chamber" is used herein to refer to a physical structure that substantially surrounds the volume in which a sample (typically a gas) is ionized. Such a physical structure can also form part of a mass analyzer; for example, an ion trap, in which electron bombardment or chemical ionization occurs.

[0033] As used herein, the terms "silicon hydride" or "SiH" refer to the decomposition products of SiH4 after thermal decomposition on a surface. In some cases, the decomposition of SiH4 on a surface can lead to the formation of a silicon (Si) layer, accompanied by the loss of H2. In some cases, the loss of H2 may be incomplete, in which case a portion of the silicon may contain Si-H functional groups. Si-H functional groups can be present on the surface of the silicon layer and / or within the silicon layer.

[0034] Ion source with silicon coating

[0035] In one example, an ion source is provided. The ion source may be an electron ionization (EI) ion source or a chemical ionization (CI) ion source. The ion source includes a sample inlet and multiple components having surfaces and forming ion flow paths, wherein at least one of the components forming the ion flow paths has a surface at least partially coated with a layer of silicon (Si), silicon hydride (SiH), or a combination thereof. When the ion source is part of a device such as a mass spectrometer, in some examples, only one or more of the multiple components between the sample inlet and the ion flow outlet are coated with silicon. For example, components downstream of the ion flow outlet (such as a mass analyzer) do not have the silicon coating described herein. In one example, the surface is an inner surface, and the inner surfaces of the multiple components are at least partially coated with a layer of silicon (Si), silicon hydride (SiH), or a combination thereof. In some examples, the outer surfaces of the multiple components may also be at least partially coated with a layer of silicon (Si), silicon hydride (SiH), or a combination thereof.

[0036] When at least one of the plurality of components that enable ion flow has a surface at least partially coated with a silicon layer, the portion of any given component surface coated with silicon may be at least about 50% or less, 55%, 60%, 65%, 70%, 75%, 85%, 90%, 95%, 98%, 99%, 99.5%, or 99.9% of the surface area. The portion of any given component surface coated with silicon may be the same among all silicon-coated components, or it may be different for each particular component. In some examples, the surface of at least one of the plurality of components is conformally coated with silicon.

[0037] Figure 2 An exploded view of the various components of an electron ionization stainless steel ion source is shown. (Reference) Figure 2 The components of the ion source may include gold-plated fixing screws (101), gold-plated screws (102), interface sockets (103), ionization chambers (104), pull-out electrode posts (105), pull-out electrode plates (106), four-turn filaments (107), spring washers (108), lens insulators (109), inlet lenses (110), ion focusing lenses (111), repulsion insulators (112), repulsion electrodes (113), flat washers (114), disc spring washers (115), repulsion nut (116), source heater block assembly (117), and repulsion block inserts (118). In some examples, the plurality of components include ionization chambers (104), pull-out electrode posts (105), pull-out electrode plates (106), inlet lenses (110), ion focusing lenses (111), repulsion electrodes (113), or repulsion block inserts (118). In another example, the plurality of components includes an ionization chamber (104), a pull-out electrode post (105), or a repulsion electrode (113). In one example, the sample inlet may enter the ionization chamber (104) through the center of the interface socket (103).

[0038] Figure 3 An exploded view of the various components of an electron ionization source is shown. (Reference) Figure 3The components of the ion source may include a fixing screw (201), a screw (202), an ionization chamber (203), an extraction lens (204), an extraction lens insulator (205), a filament (206), a spring washer (207), a flat washer (207'), a lens insulator (208), an extended inlet lens assembly (209), an ion focusing lens (210), a repulsion insulator (211), a repulsion electrode (212), a flat washer (213), a disc spring washer (214), a repulsion electrode nut (215), a source heater block assembly (216), and a repulsion electrode block insert (217). In some examples, the plurality of components includes a source body, an extraction lens (204), an extended inlet lens assembly (209), an ion focusing lens (210), a repulsion electrode (212), and a repulsion electrode block insert (217). In one example, the plurality of components includes a source body, an extraction lens (204), or a repulsion electrode (212). In one example, Figure 3 The ion source in the ionization chamber can be configured to have its voltage set separately from the extraction lens (204) and the repulsion electrode (212). In some examples, with Figure 2 Compared to the ion source in the middle, Figure 3 The ion source in the medium can have a signal response that is about 2 to about 4 times greater.

[0039] Figure 4 An exploded view of the various components of an electron ionization source is shown. (Reference) Figure 4 The components of the ion source may include a source finger gripper (301), a filament block (302), an extraction lens (303), a ceramic insulator for the extractor (304), an extended inlet lens assembly (305), an ion focusing lens (306), a lens insulator / support (307), a gold-plated screw (308), a source body (309), a rear extraction lens 2 (310), a rear extraction lens 1 (311), a gold-plated screw (312), a locking ring lens insulator (313), a high-efficiency dual filament (314), a ring heater / sensor assembly (315), a source base (316), and a repulsion assembly (317). In another example, the plurality of components includes one of the source body (309), the rear extraction lens 2 (310), the rear extraction lens 1 (311), or the repulsion assembly (317). In one example, Figure 4 The ion source in the ionization chamber can be configured to have its voltage set separately from the extraction lens (303), the post-extraction lens 2 (310), the post-extraction lens 1 (311), and the repulsion assembly (317). In some examples, with Figure 2 Compared to the ion source in the middle, Figure 4 The ion source in the medium can have a signal response of about 10 to about 20 times.

[0040] The plurality of components may include one, two, three, four, five, or six partially coated components, such as the partially silicon coated components described herein.

[0041] In various examples, the silicon layer can be approximately... To date (Å) thick. In some examples, the silicon layer can be approximately... to approximately about to approximately about to approximately about to approximately about to approximately or about to approximately Thick. The silicon layer can be approximately or about Thickness. The silicon-coated components described herein may have silicon layers of substantially the same or similar thickness, or each silicon-coated component may have a silicon layer of a different thickness than other components. Known techniques, including CVD (chemical vapor deposition), ALD (atomic layer deposition), PVD (physical vapor deposition), sputtering, evaporation, electroplating, etc., can be used to deposit silicon layers onto the components.

[0042] In various examples, the silicon layer may be at least 97%, 98%, 99%, 99.5%, 99.9%, or 99.99% pure silicon. In some examples, the silicon layer may contain about 0.001% to about 3% hydrogenated silicon. In some examples, the silicon layer may contain less than about 3%, 2%, 1%, 0.5%, 0.25%, 0.1%, 0.05%, or 0.001% hydrogenated silicon.

[0043] In one example, the ion source may include a source chamber, a pull-out electrode post (105), a pull-out electrode plate (106), an inlet lens (110), an ion focusing lens (111), a repulsion electrode (113), a repulsion electrode block insert (118), an extraction lens, an inlet lens (110), an ion focusing lens (111), at least one post-extraction lens, or a combination thereof, wherein at least one of the source chamber, pull-out electrode post, pull-out electrode plate, inlet lens, ion focusing lens, repulsion electrode, repulsion electrode block insert, extraction lens, inlet lens, ion focusing lens, or at least one post-extraction lens is at least partially coated with a silicon layer. In another example, the ion source is one of an electron ionization high-efficiency source, an electron ionization inert extraction source, or an electron ionization stainless steel source.

[0044] While this disclosure describes specific portions suitable for silicon coating as described herein, the benefits and advantages of silicon coating may also be obtained by coating other portions of the mass spectrometer not specifically mentioned herein. For example, for any portion of an ion source that comes into contact with ions in high-temperature environments and in the presence of reactive gases such as hydrogen, if that portion is coated with silicon, it may provide the benefits and advantages described herein compared to when it is uncoated. These portions may include those present in other types of instruments, such as ion traps, single quadrupole mass spectrometers, triple quadrupole mass spectrometers, quadrupole time-of-flight mass spectrometers, etc.

[0045] Sample analysis methods

[0046] In one example, a mass spectrometer incorporating the ion source described herein is provided. In other examples, a gas chromatography-mass spectrometry (GC-MS) system incorporating the ion source described herein is provided.

[0047] In one example, a method is provided for analyzing a sample using a mass spectrometer including an ion source described herein. The method includes flowing the sample in a carrier gas through a sample inlet, ionizing the sample by at least one of a plurality of components forming an ion flow path to provide ions, and analyzing the ions based on their mass. The ionization may be electronic ionization or chemical ionization. In some examples, the method also includes a gas chromatograph capable of operating in conjunction with the mass spectrometer.

[0048] The sample can be any suitable sample capable of entering the gas phase for mass spectrometry analysis. The sample may contain one or more groups known to be readily hydrogenated by hydrogen under conditions found in a mass spectrometer, such as nitro, carbon-carbon double bonds, carbonyl, etc.

[0049] In some examples, the carrier gas includes at least one of hydrogen (H2) or helium (He). In other examples, the carrier gas is a mixture of hydrogen and an inert gas (such as helium, nitrogen, or argon). There is no particular limitation on the relative ratio of hydrogen to the inert gas, and it can include hydrogen:inert gas ratios of 99:1, 95:5, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, 10:90, 5:95, or 1:99. The method may also include infusing a conditioning gas into the mass spectrometer, wherein the conditioning gas is different from the carrier gas. As used herein, the term "conditioning gas" generally refers to a gas capable of cleaning or otherwise bringing the ion source and / or other components or areas of the mass spectrometer to conditions that improve or optimize the performance of the mass spectrometer. The conditioning gas can be used according to the method described in U.S. Patent No. 8,378,293, which is incorporated herein by way of its entirety. In some examples, the conditioning gas includes hydrogen. In other examples, the carrier gas includes at least one of helium, nitrogen, or argon.

[0050] In various examples, the method reduces the reactivity between the sample and the carrier gas, reduces or eliminates tailing in ion chromatograms, or improves mass spectrometry fidelity.

[0051] Example

[0052] Various examples of this application can be better understood by referring to the following illustrative embodiments. The scope of this application is not limited to the embodiments given herein.

[0053] Comparative Example 1: Spectral fidelity of nitrobenzene

[0054] Figures 5A to 5D The problems with hydrogenating nitrobenzene from a source using hydrogen as a carrier gas are illustrated. Figure 5A shows the spectrum of a nitrobenzene reference library from NIST Library 17. This is how the spectrum appears when helium is used as the carrier gas. The abundance of ion 93 should be about 20% of that of ion 123. Figure 5B is the spectrum obtained using a 3 mm pull-out lens with hydrogen as the carrier gas. The relative abundance in the spectrum is severely distorted, and searching it against the NIST spectral library will give an incorrect identification as aniline, which is a hydrogenation product of nitrobenzene. Figure 5C shows the reaction of nitrobenzene with hydrogen to form aniline. Figure 5D shows the extracted ion chromatograms (EIC) of ions 77, 93, and 123. Normally, EICs would be expected to have the same peak shape. However, as shown in Figure 5D, the 93 EIC has a severe tail, while the others do not.

[0055] Example 2: Spectral fidelity of nitrobenzene using silicon-coated components

[0056] Figure 6 The EIC of the nitrobenzene peaks obtained using a structure with a 9mm pulled-out polarimeter (Prior Art Attempt 1), a structure using a graphite portion / layer (Previous Attempt 2), and a structure with a silicon-coated component (designated "the present invention") were compared. Ideally, the abundance of 93 was approximately 20% of 123. In some examples, the structure with the silicon-coated component produced the spectrum closest to the reference. The spectrum was correctly identified as nitrobenzene. Similar results were obtained from tests evaluating other nitro compounds, thymol (a common aromatic compound), and fenitrothion (an insecticide). In all these tests, the structure with the silicon-coated component gave the most accurate results.

[0057] Example 3: Chromatographic tailing of high-boiling-point compounds in the source

[0058] An important test in evaluating GC / MS sources is measuring peak tailing of the analyte. Peak asymmetry can be caused by a variety of factors, such as adsorption or decomposition at active sites in the source, or lower temperatures within the source. A useful test is to analyze peak tailing from normal C... 10 To the positive structure C40 A series of homologous n-alkanes. Lower alkanes should not have temperature-related issues with the source component, as their boiling points are much lower than the source temperature during testing (typically 350°C (maximum)). Alkanes are very stable, and if any tailing is caused by reactivity, it will typically show minimal tailing. Therefore, lower alkanes are not expected to have tailing. When a series of alkanes is eluted from the column to the source, higher-boiling homologues may exhibit increasingly larger tails if there are problems with the source.

[0059] Figure 7A shows the positive configuration C operated with previous attempts 1 and 2, compared to the structure with silicon-coated components (“the present invention”). 10 To the positive structure C 40 Chromatograms of the test sample. These signals are the responses at mass 57, normalized to normal C. 13 The peak height helps in the comparison. Note that in Figure 7A, the alkane from the previous attempt 2 (graphite) is used at approximately n-C. 26 It begins to show increased tailing. The chromatogram in Figure 7B shows the normal C 28 To the positive structure C 31 The peak shapes of alkanes are shown in the development diagram. Previous attempt 1 and the present invention exhibit ideal symmetry, while the peak shape of previous attempt 2 is very poor. The tailing of previous attempt 2 is so severe that the signal height drops to a fraction of the signal height of the most recently eluted alkanes in previous attempt 1 and the present invention. Both previous attempt 1 and the present invention provide acceptable performance in alkane testing, while previous attempt 2 does not. Tailing of higher boiling point compounds has also been observed in other classes of compounds when using previous attempt 2. For example, tailing can be observed in pharmaceuticals, polyaromatic hydrocarbons (PAHs), and pesticides.

[0060] Figure 8 This demonstrates the problems with the insecticide ethoxysulfuron. This compound exhibits issues with the normal C... 28 Elution occurred within the same retention time range. Similar to alkanes, previous attempt 2 exhibited significantly more tailing compared to previous attempt 1 and the present invention.

[0061] Example 4: Spectral fidelity of PAH

[0062] Previous attempt 2 (graphite) showed another problem related to spectral fidelity for higher boiling point PAHs. Unlike the other two schemes, it produced incorrectly high-quality ions in the spectrum, especially near the molecular ion. Figure 9The spectra of benzo[ghi]pyrene obtained using previous attempts 1 and 2, as well as the present invention, are shown. Boxes in the spectrum of previous attempt 2 indicate foreign ions. These ions lower the library match value when the spectrum is retrieved against a reference library. For the analysis of unknowns in spectral interpretation, these foreign ions greatly obscure the process. The same problem exists with other PAHs (such as benzo[b]fluoranthene) and the internal standard perylene-D12.

[0063] Example 5: Linearity of the semi-volatile calibration curve

[0064] Some regulated GC / MS methods, such as EPA Method 8270 for semi-volatile pollutants, impose requirements on the linearity that must be achieved during initial calibration. Laboratories strive to achieve a relative standard deviation (RSD) of less than 20% for the response factor within the calibration range. This is challenging even with helium as a carrier gas, but even more difficult with hydrogen. The examples below illustrate calibration results using previous attempts 1 and 2, as well as the rapid 8270 calibration performed on the same instrument using the present invention. Table 1 shows the percentage RSD of calibration results for several compounds. As shown in Table 1, for most compounds, the calibration performance of the present invention is comparable to or better than other methods.

[0065] Table 1: Percent RSD of calibration response factor for several EPA Method 8270 compounds.

[0066]

[0067]

[0068] The terms and expressions used herein are descriptive and not restrictive, and their use is not intended to exclude any equivalents of the features shown and described or portions thereof. However, it should be understood that various modifications are possible within the scope of the claimed embodiments of this application. Therefore, it should be understood that although this application describes specific embodiments and optional features, modifications and variations can be made to the compositions, methods, and concepts disclosed herein by those skilled in the art, and such modifications and variations are considered to be within the scope of the embodiments of this application.

Claims

1. A mass spectrometer including an ion source, said ion source comprising: Sample inlet; and A plurality of components forming an ion flow path, wherein two or more surfaces of the plurality of components forming the ion flow path are at least partially coated with a layer of silicon (Si), silicon hydride (SiH), or a combination thereof, wherein the plurality of components include an ionization chamber, a pull-out electrode post, a pull-out electrode plate, an inlet lens, an ion focusing lens, a repulsion electrode, and a repulsion electrode insert.

2. The mass spectrometer according to claim 1, wherein, The surface is conformally coated with silicon.

3. The mass spectrometer according to claim 1, wherein, The layer is 50 to 1200 angstroms thick.

4. The mass spectrometer according to claim 3, wherein, The layer is 400 to 1000 angstroms thick.

5. The mass spectrometer according to claim 1, wherein, The ion source is an electron ionization (EI) ion source or a chemical ionization (CI) ion source.

6. The mass spectrometer according to claim 1, wherein, The plurality of components includes one of an ionization chamber, a pull-out electrode, or a repulsion electrode.

7. A gas chromatography-mass spectrometry (GC-MS) instrument, comprising a mass spectrometer according to any one of claims 1-6.

8. A method for analyzing a sample using a mass spectrometer comprising an ion source according to claim 1, the method comprising: The sample is allowed to flow through the sample inlet in a carrier gas. The sample is ionized by at least one of the plurality of components forming the ion flow path to provide ions; as well as The ions are analyzed based on their mass.

9. The method according to claim 8, wherein, The carrier gas includes at least one of hydrogen (H2) or helium (He).

10. The method of claim 8, further comprising flowing a conditioning gas into the mass spectrometer, wherein the conditioning gas is different from the carrier gas.

11. The method according to claim 10, wherein, The carrier gas includes at least one of helium, nitrogen, or argon.

12. The method according to claim 10, wherein, The regulating gas includes hydrogen.

13. The method according to claim 8, wherein, The ionization occurs through electronic ionization or chemical ionization.

14. The method of claim 8, further comprising a gas chromatograph configured to operate in conjunction with the mass spectrometer.

15. A mass spectrometer including an ion source, said ion source comprising a source chamber, a pull-out electrode column, a pull-out electrode plate, an inlet lens, an ion focusing lens, a repulsion electrode, a repulsion electrode block insert, an extraction lens, at least one post-extraction lens, or a combination thereof, wherein, The source chamber, pull-out electrode column, pull-out electrode plate, inlet lens, ion focusing lens, repulsion electrode, repulsion electrode block insert, extraction lens, inlet lens, ion focusing lens, or at least one post-extraction lens are at least partially coated with a silicon layer.

Images