Ion source

Abstract

To solve a problem in which there remains an unmet need for an ion source that exhibits spectral fidelity when used with hydrogen gas.SOLUTION: An ion source includes a sample entrance and a plurality of components having surfaces and defining an ion flow path, at least one surface of the plurality of components constituting the ion flow path is at least partially coated with a layer of silicon (Si), silicon hydride (SiH), or a combination thereof.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This patent application claims the benefit of priority of U.S. Patent Application No. 16 / 830,5 77, filed on March 26, 2020. The entire content of the said application is hereby incorporated by reference and made a part of this specification.

Background Art

[0002] Distortion of chromatographic peaks and mass spectra generated using a gas chromatograph or a mass spectrometer can occur when hydrogen is present as the carrier gas or when hydrogen is added as a scavenger to the ion source when helium is the carrier gas. When the molecules and ions of the analyte have an undesirable interaction with hydrogen and the material within the ionization source of the mass spectrometer, problems such as changes in the mass spectrum and distortion (tailing) of the chromatographic peak result. These problems are particularly severe in the case of analytes having functional groups or chemical bonds that can be reduced in the presence of hydrogen. In some cases, the main ion of the analyte shows a peak without tailing, but the total ion chromatogram (TIC) has a substantial tail caused by the decomposition products formed by the reaction of hydrogen with the compound.

[0003]

[0004] ​​​​​​​​​The problem of mass spectrum distortion can be severe. For some compounds the reference library spectra used for identification can change such that the analyte is misidentified as a different compound (e.g., the mass spectrum database of the National Institute of Standards and Technology (NIST)).

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] Therefore, the need for an ion source that exhibits spectral fidelity when used with hydrogen gas remains unmet. The present disclosure provides a solution to this need.

MEANS FOR SOLVING THE PROBLEM

[0006] In one aspect, an ion source is provided, the ion source comprising a sample entrance and a plurality of components having surfaces and forming an ion flow path, wherein at least one surface of the plurality of components forming the ion flow path is at least partially coated with a layer of silicon (Si), silicon hydride (SiH), or a combination thereof.

[0007] In another aspect, a method of analyzing a sample using a mass spectrometer includes using the ion source described herein. The method includes flowing a sample through a sample entrance in a carrier gas and applying energy to at least one of the plurality of components forming the ion flow path to provide ions. and applying energy to at least one of the plurality of components forming the ion flow path to provide ions. Ionizing a sample and analyzing ions based on ion mass comprises.

[0008] In a further aspect, an ion source is provided, the ion source comprising an ion source chamber, a drawout cylinder, a drawout plate, an entrance lens, an ion focus lens, a repeller, a repeller block insert, an extractor lens, at least one post-extractor lens, or a combination thereof, wherein at least one of the ion source chamber, the drawout cylinder, the drawout plate, the entrance lens, the ion focus lens, the repeller, the repeller block insert, the extractor lens, or at least one post-extractor lens is at least partially coated with a layer of silicon. drawout cylinder, a drawout plate, an entrance lens, an ion focus lens, a repeller, a repeller block insert, an extractor lens, at least one post-extractor lens, or a combination thereof, wherein at least one of the ion source chamber, the drawout cylinder, the drawout plate, the entrance lens, ion focus lens, a repeller, a repeller block insert, an extractor lens, or at least one post-extractor lens is at least partially coated with a layer of silicon.

[0009] In yet another aspect, when using hydrogen as a carrier gas or adding hydrogen as a scavenger to the ion source when helium is the carrier gas, the distortion of mass spectra or chromatographic peaks when using gas chromatography or a mass spectrometer is a persistent problem. Advantageously, in some examples, the ion sources described herein improve performance for compounds such as hydrogenatable nitrobenzene and 3-nitroaniline, resulting in higher spectral match values and more accurate identification when performing a search in a reference spectral library. For some compounds such as nitrobenzene, the EICs for the main ions are different. hydrogen as a scavenger to the ion source when helium is the carrier gas, the distortion of mass spectra or chromatographic peaks when using gas chromatography or a mass spectrometer is a persistent problem. Advantageously, in some examples, the ion sources described herein improve performance for compounds such as hydrogenatable nitrobenzene and 3-nitroaniline, resulting in higher spectral match values and more accurate identification when performing a search in a reference spectral library. For some compounds such as nitrobenzene, the EICs for the main ions are different. when using gas chromatography or a mass spectrometer is a persistent problem. Advantageously, in some examples, the ion sources described herein improve performance for compounds such as hydrogenatable nitrobenzene and 3-nitroaniline, resulting in higher spectral match values and more accurate identification when performing a search in a reference spectral library. For some compounds such as nitrobenzene, the EICs for the main ions are different. Advantageously, in some examples, the ion sources described herein improve performance for compounds such as hydrogenatable nitrobenzene and 3-nitroaniline, resulting in higher spectral match values and more accurate identification when performing a search in a reference spectral library. For some compounds such as nitrobenzene, the EICs for the main ions are different. improve performance for compounds such as hydrogenatable nitrobenzene and 3-nitroaniline, resulting in higher spectral match values and more accurate identification when performing a search in a reference spectral library. For some compounds such as nitrobenzene, the EICs for the main ions are different. resulting in higher spectral match values and more accurate identification when performing a search in a reference spectral library. For some compounds such as nitrobenzene, the EICs for the main ions are different. when performing a search in a reference spectral library. For some compounds such as nitrobenzene, the EICs for the main ions are different. ​​Since it shows the tailing of the degree, it becomes difficult to integrate and identify by the qualifier ratio. Advantageously, in some examples, the ion source described herein reduces or eliminates tailing in the total ion chromatogram (TIC) and the extracted ion chromatogram (EIC).

[0010] Some of the further features and advantages of the various examples are shown in part in the following description, and some will become apparent from the description or can be learned by implementing the various examples. The objectives and other advantages of the various examples will be realized and achieved by the components and combinations specifically pointed out in the description herein.

[0011] The drawings generally illustrate the various examples of this patent application as examples and are not limiting.

Brief Description of the Drawings

[0012]

Figure 1

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Mode for Carrying Out the Invention

[0013] Throughout all the drawings, the same part numbers indicate the same or similar parts.

[0014] Hereinafter, certain specific examples of the disclosed subject matter will be referred to in detail. Some of the examples of the disclosed subject matter are shown in the accompanying drawings. The disclosed subject matter will be described in conjunction with the recited claims, but it will be understood that the exemplary subject matter is not intended to limit the claims to the disclosed subject matter.

[0015] Throughout this document, values expressed in a range format include not only the numerical values explicitly recited as the upper and lower limits of the range but also all individual numerical values or sub-ranges subsumed within that range, and should be interpreted flexibly as if each numerical value and sub-range were explicitly recited. For example, a range of "about 0.1% to about 5%" or "about 0.1% to 5%" includes not only about 0. 1% to about 5%, but also the individual values (e.g., 1%, 2%, 3%, and 4%) and sub-ranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4 .4%) within the indicated range. A description of "about X to Y" has the same meaning as "about X to about Y" unless otherwise indicated. Similarly, a description of "about X, Y, or about Z" has the same meaning as "about X, about Y, or about Z" unless otherwise indicated. In this document, the terms "a", "an", or "the" are used to mean one or more than one, unless otherwise clearly defined in context. The term "or" is used to mean a non-exclusive "or" unless otherwise indicated. A description of "at least one of A and B" or "at least one of A or B" means "A, B, or both".

[0016] In this document, the terms "a", "an", or "the" are used to mean one or more than one, unless otherwise clearly defined in context. The term "or" is used to mean a non-exclusive "or" unless otherwise indicated. A description of "at least one of A and B" or "at least one of A or B" means "A, B, or both". In this document, the terms "a", "an", or "the" are used to mean one or more than one, unless otherwise clearly defined in context. The term "or" is used to mean a non-exclusive "or" unless otherwise indicated. A description of "at least one of A and B" or "at least one of A or B" means "A, B, or both". B, or has the same meaning as "A and B". In addition, expressions or terms used in this specification that are not otherwise defined are for illustrative purposes only and are not intended to be limiting It will be understood. The use of section headings is intended to assist in reading the document and is not to be construed as limiting, and the information related to the section heading may occur within or outside that particular section. All publications, patents, and patent documents cited in this document are hereby incorporated by reference in their entirety as if each were individually incorporated by reference to form a part of this specification.

[0017] In the methods described herein, unless a temporal or operational sequence is explicitly recited the operations can be performed in any order. Further, the operations described in detail can be performed simultaneously unless they are recited in the words of an explicit claim as being performed separately. For example, the operation of performing X described in a claim and the operation of performing Y described in a claim can be performed simultaneously within a single operation and the resulting process will fall within the literal scope of the process described in the claim .

[0018] [Definitions] As used herein, the term "about" can allow for some variability in a value or range such as, for example, within 10%, within 5%, or within 1% of the limits of the recited value or recited range and includes the recited exact value or range.

[0019] As used herein, the term "substantially" means at least Also 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%, refers to a majority or a substantial portion.

[0020] As used herein, the term "inner surface" refers to any surface within a chamber, such as an ionization chamber, other enclosure, or component that can undergo an undesirable interaction with the analyte. This term includes surfaces of components that are not part of the chamber but are disposed within the chamber, such as means for introducing a sample, a repeller, an extractor lens, and a drawout plate, etc., that can undergo an undesirable interaction with the analyte.

[0021] As used herein, the term "outer surface" refers to a portion of the surface of a component that is at least partially exposed to the atmosphere or the environment during the operation of the ion source described herein. The outer surface can be coated with silicon, but the coating on this outer surface does not contribute to the improvement of the spectral fidelity described herein.

[0022] The term "ionization chamber" is used herein to refer to a solid structure that substantially encloses the volume in which a sample, typically a gas, is ionized. The solid structure can also form part of a mass spectrometer. ​​​​​​​​​​​For example, an ion trap in which electron impact or chemical ionization occurs inside can also be configured. It can be done.

[0023] As used in this specification, the term "silicon hydride" or "SiH" refers to the decomposition product of SiH4 after being thermally decomposed on the surface. In some examples, the decomposition of SiH4 on the surface results in the formation of a silicon (Si) layer, and H2 may be lost accordingly. In some examples, the loss of H2 may be incomplete, and in these cases, a portion of the silicon may contain Si-H functional groups. The Si-H functional groups may be present on the surface and / or inside the silicon layer. In some cases, the decomposition of SiH4 on the surface results in the formation of a silicon (Si) layer, and H2 may be lost accordingly. In some cases, the loss of H2 may be incomplete, and in these cases, a portion of the silicon may contain Si-H functional groups. The Si-H functional groups may be present on the surface and / or inside the silicon layer. The Si-H functional groups may be present on the surface and / or inside the silicon layer.

[0024] [Ion Source with Silicon Layer Coating] In one example, an ion source is provided. The ion source can be an electron ionization (EI) ion source or a chemical ionization (CI) ion source. The ion source includes a sample inlet and a plurality of components having a surface and constituting an ion flow path, and at least one surface of the plurality of components constituting the ion flow path is at least partially coated with a layer of silicon (Si), silicon hydride (SiH), or a combination thereof. When the ion source is part of an apparatus such as a mass spectrometer, in some examples, only one or more of the plurality of components between the sample inlet and the ion outlet are coated with silicon. For example, components such as a mass spectrometer downstream of the ion flow outlet do not have the silicon coating described in this specification. One The ion source can be an electron ionization (EI) ion source or a chemical ionization (CI) ion source. The ion source includes a sample inlet and a plurality of components having a surface and constituting an ion flow path, and at least one surface of the plurality of components constituting the ion flow path is at least partially coated with a layer of silicon (Si), silicon hydride (SiH), or a combination thereof. When the ion source is part of an apparatus such as a mass spectrometer, in some examples, only one or more of the plurality of components between the sample inlet and the ion outlet are coated with silicon. The ion source includes a sample inlet and a plurality of components having a surface and constituting an ion flow path, and at least one surface of the plurality of components constituting the ion flow path is at least partially coated with a layer of silicon (Si), silicon hydride (SiH), or a combination thereof. When the ion source is part of an apparatus such as a mass spectrometer, in some examples, only one or more of the plurality of components between the sample inlet and the ion outlet are coated with silicon. For example, components such as a mass spectrometer downstream of the ion flow outlet do not have the silicon coating described in this specification. One For example, components such as a mass spectrometer downstream of the ion flow outlet do not have the silicon coating described in this specification. One For example, components such as a mass spectrometer downstream of the ion flow outlet do not have the silicon coating described in this specification. One In an example, the surface is an inner surface, and the inner surfaces of the plurality of 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 plurality of components can also be at least partially coated with a layer of silicon (Si), silicon hydride (SiH), or a combination thereof. If at least one surface of the plurality of components that make up the ion flow is at least partially coated with a layer of silicon, the portion of the surface of any given component coated with silicon can be at least about 50%, 55%, 60%, 65%, 70%, 75%, 85%, 90%, 95%, 98%, 99%, 99.5%, or

[0025] 99.9% or equal thereto. The portion of the surface of any given component coated with silicon can be the same among all coated components, or different for each specific component. In some examples, at least one surface of the plurality of components is conformally coated with silicon.

[0026]

[0026] Figure 2 shows an exploded view of various components of an electron ionization stainless steel ion source. Referring to Figure 2, the components of the ion source are a gold-plated stop screw 101, a gold-plated screw 102, an interface socket 103, an ionization chamber 104, a draw-out cylinder 105, a draw-out plate 106, a four-turn filament 10 ​7. Spring washer 108, lens insulator 109, entrance lens 110, ion focusing lens 111, repeller insulator 112, repeller 113, flat washer 114, Belleville spring washer 115, repeller nut 11 6, ion source heater block assembly 117, and repeller block insert 118 can be included. In some examples, the plurality of components are the ionization chamber 104 , draw-out cylinder 105, draw-out plate 106, entrance lens 11 0, ion focusing lens 111, repeller 113, or repeller block insert 11 8, including at least one of them. In another example, the plurality of components include one of the ionization chamber 104, draw-out cylinder 105, or repeller 113. In one example, the sample inlet can enter the ionization chamber 104 through the center of the interface socket 103.

[0027] Figure 3 shows an exploded view of various components of an electron ionization ion source. Referring to Figure 3, the components of the ion source are set screws 201, screws 202, ionization chamber 203, extractor lens 204, extractor lens insulator 205, filament 20 6, spring washer 207, flat washer 207, lens insulator 208, extended entrance lens assembly 209, ion focusing lens 210, repeller insulator 211, repeller 212, flat washer 213, Belleville spring washer 214, repeller nut 215, ion source heater block assembly 216, and repeller block insert 21 6, and It can include the repeller 217. In some examples, the plurality of components may include at least one of the ion source body 203, the extractor lens 204, the extended entrance lens assembly 209, the ion in-focus lens 210, the repeller 212, and the repeller block insert 217. In one example, the plurality of components includes one of the ion source body 203, the extractor lens 204, or the repeller 212. In one example, the ion source of FIG. 3 can be configured to set the voltage of the ionization chamber separately from the extractor lens 204 and separately from the repeller 212. The ion source of FIG. 3 can have a signal response that is about two to about four times greater than that of the ion source of FIG. 2 in some examples.

[0028] FIG. 4 shows an exploded view of various components of an electron ionization ion source. Referring to FIG. 4, the components of the ion source include an ion source finger grip 301, a filament block 302, an extractor lens 303, an extractor ceramic insulator 30 4, an extended entrance lens assembly 305, an ion focus lens 306, a lens insulator / holder 307, a gold-plated screw 308, an ion source body 309, a post extractor lens 2 310, a post extractor lens 1 311, a gold-plated screw 3 12, a locking ring lens insulator 313, a high-efficiency dual filament 314, a ring heater / sensor assembly 315, an ion source mount 316, and a repeller assembly 317. In another example, the plurality of components includes the ion source body 309, the post extractor lens 2 310, the post extractor lens 1 311, or ​​​​​ It includes one of the repeller assemblies 317. In one example, the ion source of FIG. 4 can be configured to set the voltage of the ionization chamber separately from the extractor lens 303, the post-extractor lens 2 310, the post-extractor lens 1 311, and separately from the repeller assembly 317. The ion source of FIG. 4 can, in some examples, have a signal response that is about 10 times to about 20 times greater compared to the ion source of FIG. 2.

[0029] The plurality of components can include one, two, three, four, five, or six partially coated components, such as components partially coated with silicon as described herein.

[0030] In various examples, the silicon layer can be from about 50 Å (angstroms) to about 1200 Å thick. The silicon layer can, in some examples, be from about 100 Å to about 1100 Å, from about 200 Å to about 1000 Å, from about 300 Å to about 1000 Å, from about 400 Å to about 1000 Å, from about 500 Å to about 1000 Å, or from about 600 Å to about 1000 Å thick. The silicon layer can be about 50 Å, 100 Å, 200 Å, 300 Å, 400 Å, 500 Å, 600 Å, 700 Å, 800 Å, 900 Å, 1000 Å, 1100 Å, or about 1200 Å thick. The components described herein as being coated with the silicon layer can have a silicon layer of substantially the same or similar thickness, or each component coated with the silicon layer can have a different thickness from other components. It can have a silicon layer. The silicon layer can be deposited on components using known techniques including CVD (chemical vapor deposition), ALD (atomic layer deposition), PVD (physical vapor deposition), sputtering, evaporation, plating techniques, etc. ition), ALD (atomic layer deposition), PVD (physical vapor deposition), sputtering, evaporation, plating techniques, etc. In various examples, the silicon layer can be made of silicon with a purity of at least 97%, 98%, 99%, 99.5%, 99.9%, or 99.99%. In some examples, the silicon layer can contain about 0.001% to about 3% of a hydride of silicon. In some examples, the silicon layer can contain about 3%, 2%, 1%, 0.5%, 0.25%, 0.1%, 0.05%, or less than 0.001% of a hydride of silicon.

[0031] In various examples, the silicon layer can be made of silicon with a purity of at least 97%, 98%, 99%, 99.5%, 99.9%, or 99.99%. In some examples, the silicon layer can contain about 0.001% to about 3% of a hydride of silicon. In some examples, the silicon layer can contain about 3%, 2%, 1%, 0.5%, 0.25%, 0.1%, 0.05%, or less than 0.001% of a hydride of silicon. In some examples, the silicon layer can contain about 0.001% to about 3% of a hydride of silicon. In some examples, the silicon layer can contain about 3%, 2%, 1%, 0.5%, 0.25%, 0.1%, 0.05%, or less than 0.001% of a hydride of silicon. In some examples, the silicon layer can contain about 0.001% to about 3% of a hydride of silicon. In some examples, the silicon layer can contain about 3%, 2%, 1%, 0.5%, 0.25%, 0.1%, 0.05%, or less than 0.001% of a hydride of silicon. In some examples, the silicon layer can contain about 3%, 2%, 1%, 0.5%, 0.25%, 0.1%, 0.05%, or less than 0.001% of a hydride of silicon. In some examples, the silicon layer can contain about 3%, 2%, 1%, 0.5%, 0.25%, 0.1%, 0.05%, or less than 0.001% of a hydride of silicon.

[0032] In one example, the ion source can include an ion source chamber, a draw-out cylinder 105, a draw-out plate 106, an entrance lens 110, an ion focus lens 111, a repeller 113, a repeller block insert 118, an extractor lens, an entrance lens 110, an ion focus lens 111, at least one post-extractor lens, or a combination thereof, and the ion source chamber, draw-out cylinder, draw-out plate, entrance lens, ion focus lens, repeller, repeller block insert, extractor lens, entrance lens, ion focus lens, or at least one post-extractor lens can include at least one of them. In one example, the ion source can include an ion source chamber, a draw-out cylinder 105, a draw-out plate 106, an entrance lens 110, an ion focus lens 111, a repeller 113, a repeller block insert 118, an extractor lens, an entrance lens 110, an ion focus lens 111, at least one post-extractor lens, or a combination thereof, and the ion source chamber, draw-out cylinder, draw-out plate, entrance lens, ion focus lens, repeller, repeller block insert, extractor lens, entrance lens, ion focus lens, or at least one post-extractor lens can include at least one of them. In one example, the ion source can include an ion source chamber, a draw-out cylinder 105, a draw-out plate 106, an entrance lens 110, an ion focus lens 111, a repeller 113, a repeller block insert 118, an extractor lens, an entrance lens 110, an ion focus lens 111, at least one post-extractor lens, or a combination thereof, and the ion source chamber, draw-out cylinder, draw-out plate, entrance lens, ion focus lens, repeller, repeller block insert, extractor lens, entrance lens, ion focus lens, or at least one post-extractor lens can include at least one of them. In one example, the ion source can include an ion source chamber, a draw-out cylinder 105, a draw-out plate 106, an entrance lens 110, an ion focus lens 111, a repeller 113, a repeller block insert 118, an extractor lens, an entrance lens 110, an ion focus lens 111, at least one post-extractor lens, or a combination thereof, and the ion source chamber, draw-out cylinder, draw-out plate, entrance lens, ion focus lens, repeller, repeller block insert, extractor lens, entrance lens, ion focus lens, or at least one post-extractor lens can include at least one of them. In one example, the ion source can include an ion source chamber, a draw-out cylinder 105, a draw-out plate 106, an entrance lens 110, an ion focus lens 111, a repeller 113, a repeller block insert 118, an extractor lens, an entrance lens 110, an ion focus lens 111, at least one post-extractor lens, or a combination thereof, and the ion source chamber, draw-out cylinder, draw-out plate, entrance lens, ion focus lens, repeller, repeller block insert, extractor lens, entrance lens, ion focus lens, or at least one post-extractor lens can include at least one of them. In one example, the ion source can include an ion source chamber, a draw-out cylinder 105, a draw-out plate 106, an entrance lens 110, an ion focus lens 111, a repeller 113, a repeller block insert 118, an extractor lens, an entrance lens 110, an ion focus lens 111, at least one post-extractor lens, or a combination thereof, and the ion source chamber, draw-out cylinder, draw-out plate, entrance lens, ion focus lens, repeller, repeller block insert, extractor lens, entrance lens, ion focus lens, or at least one post-extractor lens can include at least one of them. In one example, the ion source can include an ion source chamber, a draw-out cylinder 105, a draw-out plate 106, an entrance lens 110, an ion focus lens 111, a repeller 113, a repeller block insert 118, an extractor lens, an entrance lens 110, an ion focus lens 111, at least one post-extractor lens, or a combination thereof, and the ion source chamber, draw-out cylinder, draw-out plate, entrance lens, ion focus lens, repeller, repeller block insert, extractor lens, entrance lens, ion focus lens, or at least one post-extractor lens can include at least one of them. In one example, the ion source can include an ion source chamber, a draw-out cylinder 105, a draw-out plate 106, an entrance lens 110, an ion focus lens 111, a repeller 113, a repeller block insert 118, an extractor lens, an entrance lens 110, an ion focus lens 111, at least one post-extractor lens, or a combination thereof, and the ion source chamber, draw-out cylinder, draw-out plate, entrance lens, ion focus lens, repeller, repeller block insert, extractor lens, entrance lens, ion focus lens, or at least one post-extractor lens can include at least one of them. One is at least partially coated with a layer of silicon. In another example, the ion source is one of an electron ionization high efficiency ion source, an electron ionization inert extractor ion source, or an electron ionization stainless steel ion source.

[0033] The present disclosure describes specific components that may be suitable for coating with the silicon layer described herein. However, the benefits and advantages of the silicon coating can also be obtained when other components of the mass spectrometer not specifically mentioned herein are coated. For example, for any component of the ion source that comes into contact with ions in the presence of a high temperature environment and reactive gases such as hydrogen, if that component is coated with silicon rather than not coated, it can lead to the benefits and advantages described herein. These components can include, for example, those found in other types of instruments such as ion traps, single quadrupole mass spectrometers, triple quadrupole mass spectrometers, quadrupole time-of-flight mass spectrometers, etc. (single quadrupole mass spectrometer), triple quadrupole mass spectrometers, quadrupole time-of-flight mass spectrometers (quadrupole time-of-flight mass spectrometer), etc.

[0034] [Method for Analyzing a Sample] In one example, a mass spectrometer housing the ion source described herein is provided. In another example, a gas chromatograph mass spectrometer housing the ion source described herein is provided.

[0035] In one example, a sample is analyzed using a mass spectrometer comprising the ion source described herein. A method is provided. The method includes flowing a sample through a sample inlet in a carrier gas and , ionizing the sample by at least one of a plurality of components that make up an ion flow path to provide ions, and analyzing the ions based on ion mass. Ionization can be by electron ionization or chemical ionization. In some examples, the method further comprises a gas chromatograph operable with a mass spectrometer. The sample can be any suitable sample that can enter the gas phase for mass spectral analysis. The sample can contain one or more groups known to be prone to hydrogenation by hydrogen under the conditions found in a mass spectrometer, such as nitro groups, carbon-carbon double bonds, carbonyl groups, etc. In some examples, the carrier gas contains 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. The relative ratio of hydrogen to the inert gas is not particularly limited and 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.

[0036] The method can further include flowing a conditioning gas into the mass spectrometer, where the conditioning gas is different from the carrier gas. As used herein, "conditioning gas"

[0037]

[0037] 0:50, 40:60, 30:70, 20:80, 10:90, 5:95, or 1:99 The method can further include flowing a conditioning gas into the mass spectrometer, where the conditioning gas is different from the carrier gas. As used herein, "conditioning gas" The term "conditioning gas" generally refers to a gas that can clean the ion source and / or other components (i.e., the ion source or other components or both) or regions of a mass spectrometer or otherwise improve or optimize the performance of the mass spectrometer. The conditioning gas can be used based on the method described in U.S. Patent No. 8,378,293, which is incorporated herein by reference in its entirety. In some examples, the conditioning gas contains hydrogen. In other examples, the carrier gas contains at least one of helium, nitrogen, or argon. In various examples, the method reduces the reactivity between the sample and the carrier gas, reduces or eliminates tailing in the ion chromatogram, or improves mass spectrometer fidelity.

[0038]

[0039] [Experimental Examples] The various examples of this patent application can be better understood by referring to the following examples presented as experimental examples. The scope of this patent application is not limited to the examples given herein.

[0040] [Comparative Example 1: Spectrum Fidelity of Nitrobenzene] Figures 5A - 5D show the problem of hydrogenation of nitrobenzene in an ion source using a hydrogen carrier gas. Figure 5A is the reference library spectrum of nitrobenzene from the NIST17 library. This shows how the spectrum appears when helium is used as the carrier gas. The abundance of the 93 ion should be about 20% of the 123 ion. Figure 5B shows the spectrum of nitrobenzene in an ion source using a 3 mm draw - out lens and a hydrogen carrier gas. ​​​​​​​​​​​​​​It is a spectrum obtained using gas. The relative abundances within the spectrum are highly distorted, When this is searched in the NIST spectral library, it can be misidentified as a certain aniline, which is a product of the hydrogenation of nitrobenzene. Figure 5C shows the reaction of nitrobenzene with hydrogen to form aniline. Figure 5D shows the extracted ion chromatogram (EIC) for ions 77, 93, and 123. Normally, the EIC is expected to have the same peak shape. However, as seen in Figure 5D, the EIC for 93 has a large tail while the others do not.

[0041] [Example 2: Spectral Fidelity When Using Components Coated with Silicon] Figure 6 compares the EICs for the nitrobenzene peak when using a configuration with a 9 mm draw-out lens (Pilot Trial 1) and a configuration using graphite components / layers (Pilot Trial 2) as well as a configuration having components coated with silicon (shown as "the present invention"). Ideally, the abundance of 93 should be approximately 20% of that of 123. In some cases, the configuration with components coated with silicon produced the spectrum closest to the reference. The spectrum was correctly identified as nitrobenzene. Similar results were obtained in tests evaluating other nitro-containing compounds, musk ketone, common aromatic compounds, and phenylthion (an insecticide). In all of these tests, the configuration with components coated with silicon produced the most accurate results.

[0042] ​​​​​​​​​​​​​​​[Example 3: Chromatographic tailing of high boiling point compounds in the ion source] One important test when evaluating a GC / MS ion source is to determine whether analyte peak tailing occurs. The asymmetry of the peaks is due to adsorption, decomposition, and / or oxidation of the ions on active sites in the ion source. This can be caused by a number of factors, such as a cold spot in the ion source or a cold spot in the ion source. -C 10 ~nC 40 The objective of this study is to analyze the homologous series of normal alkanes. has a boiling point much lower than the ion source temperature, which is typically 350°C (maximum temperature) during testing. Therefore, there should be no problems with the temperature of the components in the ion source. Even if tailing due to activity occurs, the tailing observed is generally Therefore, tailing is not expected for lower alkanes. As the alkanes elute from the column into the ion source, the higher boiling homologues are absorbed into the ion source. If there is a problem it may show a raised tail.

[0043] FIG. 7A compares a configuration with silicon coated components ("present invention"). In addition, nC using the previous trials 1 and 2 10 ~nC 40 Chromatogram of test sample measurement The signal is the response at mass 57 and is shown in nC to aid comparison. 13 Peak Height In addition, in Figure 7A, when the previous trial 2 (graphite) was used, The total number of alkanes is about nC 26 The increase in tailing starting from the cross-sectional area of ​​Figure 7B is shown. Matogram is nC 28 ~nC 31 An enlarged view of an alkane is shown. has a peak shape with the desired symmetry, while Pilot Run 2 has a very poor peak shape. The tailing for Pilot Run 2 is so bad that it drops to a small fraction of the signal height for Pilot Run 1 and the present invention for the last eluting alkane. Pilot Run 1 and the present invention both result in acceptable performance in the alkane test, while Pilot Run 2 does not. The tailing of higher boiling point compounds when using Pilot Run 2 is also observed for other classes of compounds. For example, it can also be observed for pharmaceuticals, polyaromatic hydrocarbons (PAH :polyaromatic hydrocarbon), and pesticides. Figure 8 shows the problem for the pesticide etofenprox. This compound elutes in the same retention time range as n-C

[0044] . Similar to the alkane case, Pilot Run 2 shows substantially more tailing than Pilot Run 1 and the present invention. is eluted in the same retention time range as n-C 28 . Similar to the alkane case, Pilot Run 2 shows substantially more tailing than Pilot Run 1 and the present invention. Pilot Run 2 shows substantially more tailing than Pilot Run 1 and the present invention.

[0045] [Example 4: Spectral Fidelity of PAH] Pilot Run 2 (graphite) shows another problem related to the spectral fidelity of higher boiling point PAHs. Unlike the other two solutions, Pilot Run 2 produces false higher mass ions in the spectrum, particularly close to the molecular ion. Figure 9 shows the spectra for benzo[ghi]perylene obtained using Pilot Run 1 and 2 as well as the present invention. The boxes in the spectrum of Pilot Run 2 show external ions . These ions reduce the library match value when the spectrum is searched against a reference library. When analyzing unknowns by spectral interpretation, these ions can cause misinterpretation. ions are shown. These ions reduce the library match value when the spectrum is searched against a reference library. When analyzing unknowns by spectral interpretation, these ions can cause misinterpretation. When analyzing unknowns by spectral interpretation, these Ions from the outside can greatly disrupt the process. The same problem is seen with other PAHs such as benzo[b]fluoranthene and the internal standard perylene-D12 . It is also seen.

[0046] [Example 5: Linearity of Calibration Curves for Semi-Volatiles] For some regulated GC / MS methods such as those of the Environmental Protection Agency (EPA) Method 8270 for semi-volatile contaminants, requirements are imposed on the degree of linearity that must be achieved by initial calibration. The laboratory is striving for a relative standard deviation (RSD) of the response factor for the calibration range to be less than 20%. This can be difficult even when using helium carrier gas, and is even more difficult when using hydrogen. The following examples show calibration results from the high-speed 8270 calibrations performed on the same instrument using prior trials 1 and 2 and the present invention. Table 1 shows the percent RSD of the calibration results for several compounds. As can be seen in Table 1, the calibration performance when using the present invention is equal to or better than other solutions for most compounds.

[0047]

Table 1

[0048] The terms and expressions employed herein are used as terms of explanation and not as terms of limitation. Also, the use of such terms and expressions ​​​​​​​​​​It is not intended to exclude any equivalents of the features shown and described or parts thereof, and it is recognized that various modifications are possible within the scope of the examples of this patent application. Therefore, although specific examples and optional features are described in this patent application, it should be understood that variations and modifications of the configurations, methods, and concepts disclosed herein can be entrusted to those skilled in the art, and such variations and modifications are considered to fall within the scope of the examples of this patent application. Accordingly, while specific examples and optional features are described in this patent application, variations and changes of the configurations, methods, and concepts disclosed herein may be left to those skilled in the art, and it should be understood that such variations and changes are considered to be within the scope of the examples of this patent application. Thus, although specific examples and optional features are described in this patent application, it should be understood that variations and modifications of the configurations, methods, and concepts disclosed herein can be left to those skilled in the art, and such variations and modifications are considered to be within the scope of the examples of this patent application. Hence, while specific examples and optional features are described in this patent application, it should be understood that variations and changes of the configurations, methods, and concepts disclosed herein can be entrusted to those skilled in the art, and such variations and changes are considered to be within the scope of the examples of this patent application. Therefore, it is not intended to exclude any equivalents of the features shown and described or parts thereof, and it is recognized that various modifications are possible within the scope of the examples of this patent application.

Claims

1. A sample inlet; A plurality of components constituting an ion flow path; a surface of at least one of the plurality of components that define the ion flow path; The layer is made of silicon (Si), silicon hydride (SiH), or a combination of these.

1. An ion source that is at least partially coated.

2. The ion source of claim 1 , wherein the surface is conformally coated with silicon.

3. said layer being between about 50 angstroms and about 1200 angstroms thick. Item 2. The ion source according to item 1.

4. The layer is about 400 angstroms to about 1000 angstroms thick.

4. The ion source according to claim 3.

5. The ion source may be an electron ionization (EI) ion source or a chemical ionization (CI) ion source. The ion source of claim 1 .

6. The components include an ionization chamber, a drawout cylinder, a drawout plate, and a entrance lens, entrance lens, ion focus lens, repeller, or repeller insert The ion source of claim 1 comprising at least one of:

7. The ion source of claim 6 , wherein the surface is conformally coated with silicon.

8. The plurality of components may include the ionization chamber, the draw-out cylinder, or the The ion source of claim 6 , further comprising one of a repeller.

9. A mass spectrometer comprising the ion source of claim 1.

10. A gas chromatograph mass spectrometer comprising the ion source of claim 1.

11. 13. A method of analyzing a sample using a mass spectrometer comprising the ion source of claim 1, comprising: flowing the sample through the sample inlet in a carrier gas; At least one of the plurality of components that configure the ion flow path for providing ions. ionizing the sample by one of the methods; analyzing the ions based on ion mass; The method includes:

12. The carrier gas is hydrogen (H ２ ) or helium (He) The method of claim 11 .

13. The method further comprises flowing a conditioning gas into the mass spectrometer, The method of claim 11 , wherein a cleaning gas is different from the carrier gas.

14. The carrier gas comprises at least one of helium, nitrogen, or argon; The method of claim 13.

15. The method of claim 13 , wherein the conditioning gas comprises hydrogen.

16. 13. The method of claim 1, wherein the ionizing is by electron ionization or chemical ionization.

2. The method according to claim 1.

17. a gas chromatograph configured to operate with the mass spectrometer; The method of claim 11.

18. The method includes the step of: Reduce or eliminate tailing in mass spectra or mass spectral fidelity The method of claim 11, further comprising:

19. Ion source chamber, drawout cylinder, drawout plate, entrance lens lens, ion focus lens, repeller, repeller block insert, extractor lens at least one post extractor lens, or a combination thereof; The ion source chamber, the draw-out cylinder, the draw-out plate, the end A transformer lens, the ion focus lens, the repeller, and the repeller block insert the extractor lens, the entrance lens, the ion focus lens or at least one of the at least one post extractor lens, An ion source at least partially coated with a layer of silicon.

20. The ion source may be an electron ionization high efficiency ion source, an electron ionization inert extractor, or 20. The method of claim 19, wherein the ion source is one of a stainless steel ion source, an electron ionization ion source, or an electron ionization stainless steel ion source. Ion source.

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