AND SYSTEMS AND METHODS USING THEM

[0001] PRIORITY APPLICATION

[0002] This application is related to, and claims priority to and the benefit of, U.S. Application No. 15/958,781 fried on April 20, 2018.

[0003] TECHNICAL FIELD

[0004] This relates to mass analysis, and more particularly to an ion source that relies on electron impact ionization and/or chemical ionization. A mass analyzer comprising the ion source and a reaction cell is described.

[0005] BACKGROUND

[0006] Conventional mass spectrometry techniques rely on the formation of analyte ions for analysis. Numerous ionization techniques - such as electrospray ionization, chemical ionization, and electron impact ionization techniques are known. Existing techniques, however, often lack flexibility. Accordingly, there remains a need for new ionization techniques, and apparatus and mass analyzers relying on such techniques.

[0007] SUMMARY

[0008] Certain aspects are described in reference to ion sources and mass analyzers that include ion sources and a reaction cell.

[0009] In an aspect, a mass analyzer comprises a chamber comprising a first gas inlet, a gas outlet opposite the first gas inlet, an electron inlet, and an electron collector, an electron source configured to provide electrons into the electron inlet of the chamber as an electron beam along a path between the electron source and the electron collector, and a reaction cell fluidically coupled to the gas outlet of the chamber through an inlet of the reaction cell, wherein the reaction cell comprises a rod set and a second gas inlet, wherein said reaction cell is configured to receive a second gas through the second gas inlet to permit the second gas to interact with the first gas received through the inlet of the reaction cell.

[0010] In certain embodiments, the rod set comprises a quadrupolar rod set, a hexapolar rod set or an octopolar rod set. In certain examples, the chamber comprises a charged element adjacent to the first gas inlet. In some embodiments, the mass analyzer comprises ion optics between the gas outlet and an inlet of the reaction cell. In certain examples, the mass analyzer comprises a heating element thermally coupled to the rod set of the reaction cell. In some embodiments, the electron source is configured to introduce electrons into the chamber in a path transverse to gas flow introduced through the first gas inlet. In other examples, the electron source is configured to introduce electrons into the chamber in a path that is co-axial with gas flow introduced through the first gas inlet. In some embodiments, the electron source comprises a conductive helical coil configured to provide a magnetic field to accelerate electrons into the chamber through the electron inlet

[001 1] In another aspect, a method comprises introducing a first gas into a mass analyzer comprising a chamber comprising a first gas inlet, a gas outlet opposite the first gas inlet, an electron inlet, and an electron collector to provide ionized first gas products, and providing the ionized first gas products to a down stream reaction cell fluidical!y coupled to the gas outlet of the chamber, wherein the reaction cell comprises a rod set and a second gas inlet, wherein a second gas is provided through said second gas inlet to permit the second gas to interact with the first gas received from the gas outlet of the chamber.

[0012] In certain embodiments, the ionized first gas products comprise an ionized analyte. In some instances, the second gas reacts with the ionized analyte received by the reaction cell from the gas outlet to fragment the analyte ions. In other examples, the second gas reacts with the ionized analyte received by the reaction cell from the gas outlet to provide adducts of the analyte ions. In additional embodiments, the second gas comprises at least one of ammonia, methane and isobutene. In some examples, the method comprises providing a chemical ionization gas into the chamber coaxially with the first gas. In certain examples, electrons are provided into the chamber from the electron source in a path transverse to gas flow entering through the gas inlet. In other examples, electrons are provided into the chamber from the electron source in a path coaxial to gas flow entering through the gas inlet. In some instances, the reaction cell comprises a quadrupolar rod set, a hexapolar rod set or an octopolar rod set.

[0013] In another aspect, an ion source comprises a chamber comprising a first gas inlet, a gas outlet opposite the first gas inlet, an electron inlet, and an electron collector, and an electron source comprising a conductive helical coil configured to provide a magnetic field to accelerate electrons into the chamber through the electron inlet.

[0014] In an additional aspect, a mass spectrometer comprises a sample introduction device, a mass analyzer as described herein, and a detector configured to receive selected ions from the mass analyzer.

? [0015] Additional aspects, configurations and examples are described.

[0016] BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0017] Certain configurations are described with reference to the accompanying drawings in which:

[0018] FIG. 1 is a block diagram of certain components that may be present in a mass spectrometer, in accordance with some embodiments;

[0019] FIGS 2A, 2B and 2C are illustration of quadrupo!ar, hexapolar and octopol ar rod sets, respectively, in accordance with some examples;

[0020] FIG. 3 is a schematic block diagram of a two-chamber ionization source, forming part of a mass analyzer, in accordance with some examples;

[0021] FIG. 4 is a schematic block diagram of an electron accelerator of the ionization source of FIG. 2; and

[0022] FIG. 5 is a schematic block diagram of an alternate electron impact ionization source and downstream reaction cell, forming part of a mass analyzer;

[0023] FIG. 6 is an illustration of certain ion products that can be produced by reaction with a reaction gas, in accordance with some examples; and

[0024] FIG. 7 is an illustration of certain ion products that can be produced by reaction with certain reaction gases, in accordance with some examples.

[0025] DETAILED DESCRIPTION

[0026] Certain configurations are described of a dual ionization chamber that can be used with a reaction cell to provide a mass analyzer that can be used in a mass spectrometer. In some examples, one chamber of the dual ionization chamber can be used to ionize analyte that is provided to a downstream reaction cell. For example, gaseous analyte can be introduced into a reaction ceil along with ionized gas (produced in a chamber of the ion source) to ionize the analyte within the reaction cell. Alternatively, the ion source can produce intact molecular ions and provide the intact molecular ions to the downstream reaction cell. The term“downstream” generally refers to a direction of gas flow in the system, and a downstream component is generally further away from an inlet (than an upstream component) where a gas is introduced. In some instances, a first chamber may receive electrons to permit electron bombardment of a first gas in the first chamber. A second chamber can receive a second gas and produced ions from the first chamber to permit the produced ions and second gas to interact, e.g., to collide or react. The first gas or the second gas or both may include analyte. An average axial field can be present in the reaction cell if desired. Photoionization sources can be present and positioned along an axial electron flux pathway to assist in ionizing gas or analyte or both.

[0027] In some instances, the ion sources described herein can be used to ionize a gas which is then provided to a downstream reaction cell. Gaseous analyte can be provided to the downstream reaction cell and permitted to interact with, e.g., collide or react or both, to ionize the analyte and/or form analyte adduct products. The resulting ionized analyte and/or analyte adduct products can be provided to a downstream mass filter/selector to select the ions based on mass-to-charge (m/z) ratios. The selected ions can then be detected using a detector. In other instances, the ion source may ionize the analyte prior to the analyte being provided to the downstream reaction cell [0028] Electron impact ionization sources (“El”) are widely used with GC-MS for various applications. Typically El produces higher fractions of fragment ions that are used to obtain quantitative and structural information for analytes. The use of El can result in low abundance of the parent ion. The devices and systems described herein can be used to provide intact molecular ions and also simultaneously function as a chamber for monitoring the ion-molecule reactions at a controlled pressure. While not required, a system typically comprises an ion source, a reaction cell and a mass filter/selector. For example, the ion source may comprise an integral reaction cell, or a mass analyzer may comprise an ion source and a reaction cell (and a mass filter/selector).

[0029] In certain embodiments, a schematic of certain components of a mass spectrometer are shown in FIG. 1. The system 50 comprises a sample introduction device 52, an ion source 54, a reaction cell 56, a mass filter/selector 58 and a detector 60. In some instances, the ion source 54, reaction cell 56 and mass filter/selector 58 can be present together in a mass analyzer as noted in more detail below. For example, the ion source 54, the reaction cell 56 and the mass filter/selector 58 can be present in a mass analyzer 53. While described in more detail below, the reaction cell 56 typically comprises a quadrupolar rod set 72 (see FIG. 2 A) or a hexapolar rod set 74 (see FIG. 2B) or an octopolar rod set 76 (see FIG. 2C). If desired, the rod set can be replaced with a ring guide. For example, a ring guide can provide a wide mass range confining radial field, an average axial field, and an ability to coniine the analyte. While the rods of the rod sets are shown as having a square cross section, other rod shapes can instead be used in the reaction cell.

[0030] In some embodiments, the reaction cell can be used in combination with an ion source in a mass analyzer. For example, FIGS. 3 and 5 illustrate mass analyzers 300, 300’ that incorporate two-chamber/cell ionization sources. The analyzer 300 can produce ions by way of electron impact, chemical ionization or both or other means. To that end, example mass analyzer 300 includes an ionization cell including a chemical ionization chamber 316 in a housing. The housing may be generally rectangular (with square or rectangular faces) or cylindrical in shape, formed of a generally conductive material, such a metal or alloy. Example dimensions for housing may be between about 10mm and 200mm. In an embodiment, dimensions of housing may be 24.5mm x 12mm x 25.4 mm In alternate embodiments, housing may have other shapes - preferably symmetrical about a plane - and may be right cylindrical (with circular, elliptical, rectangular, or other shaped base), spherical, or the like. Chamber 316 includes a gas inlet 340, and a gas outlet 342 located on generally opposite sides of chamber 316 Chamber outlet 342 is generally co-axial with a guide axis 320 of mass analyzer 300.

[0031 ] In certain configurations, the chamber inlet 340 may be fluidica!ly coupled to a suitable source of analyte, e.g., can be fluidically coupled to a sample introduction device 52 as shown in FIG. 1. For example, the sample introduction device 52 may be a GC system, an LC system, a nebulizer, aerosolizer, spray nozzle or head or other devices which can provide a gas or liquid sample to the ion source of the mass analyzer 300 Where solid samples are used the sample introduction device 52 may comprise a direct sample analysis (DSA) device or other devices which can introduce analyte species from solid samples. While not required, the analyte provided into the chamber inlet 340 is typically provided in gaseous form. Analyte may, for example, be supplied from a gas chromatograph, ambient sampling devices, or other suitable analyte sources [0032] Chamber inlet 340 may further permit the introduction of a second gas that may interact and react with introduced analyte to cause chemical ionization within chamber 316. The second gas may, for example, be introduced coaxially with the introduced analyte through chamber inlet 340. The second gas may chemically react with the gaseous analyte (thereby acting as a reaction gas), or simply physically bombard the gaseous analyte (thereby acting as a bombardment gas). Typically, chemical ionization is accompanied by minimal fragmentation of the analyte. If the ionization potential of the non-analyte gas is greater than the ionization potential of the analyte, production of analyte ions can be favored.

[0033] The second gas may, for example, be introduced co-axial with the introduced analyte. As will be appreciated, a suitable second gas could otherwise be introduced into chamber 316, for example, by way of a further gas inlet (not specifically illustrated) proximate chamber inlet 340 or elsewhere on the walls of chamber 316.

[0034] In some examples when chemical ionization occurs within the chamber 316, ions may be produced via collision of (neutral) analyte molecules with ions generated from an introduced reactant gas. Example chemical reactant gases include methane, ammonia, isobutane or other gases. The reactant gas is typically introduced in far excess to the target analyte so that incoming electrons preferentially ionize the reactant gas. Once the reactant gas is ionized, a variety of chemical reactions with the target analyte may occur, such as protonation [M + XI ! riS" M- H+ +X], hydride abstraction [MH + X+ -> M+ + XH], adduct formation [M + X+ - M-X+], charge exchange [M + X+ ri M+ + X] where M, MH represents the analyte, while XI ! , X+ are species derived from the reactant gas.

[0035] In some examples, a bombarding gas can be a noble gas (He, Ne, Ar, Kr, Xe), an inert gas such as nitrogen, or a simple diatomic gas such as NO or CO. If a bombarding gas is used, the bombarding gas may be ionized, and then selectively be used to ionize analytes depending on the relative ionization energies; X + e- Ά X+ (ionization of bombarding gas). X+ + M M+ + X (if ionization energy of analyte M < ionization energy of bombarding gas X). Otherwise there is no reaction. Different bombarding gases have different inherent ionization energies.

[0036] In certain examples, analyte and reaction gas travel from chamber inlet 340, on one side of chamber 316 to the opposite side thereof, and is/are ionized along its path. A charged element 346, e.g., a lens or ion optics, having a voltage applied thereto may accelerate ions within chamber 316, as they travel toward chamber outlet 342 Charged element 346 may take the form of a rectangular plate, or he formed as a hollow cylinder with, for example, having an outer diameter of about 2 mm to about 4 m and a length of about 4 to about 8 mm, with cylinder axis oriented toward the chamber outlet 342, and positioned such that the analyte travels through charged element 346 as ions exit chamber outlet 342. The applied voltage could be in the range -400 to +400 V though other voltages can be used

[0037] In some examples, multiple electron inlets 334 (FIG. 5) may be located on a further, third side of chamber 316, and allow' the introduction of electrons as a beam along a path generally transverse to the path between chamber inlet 340 and chamber outlet 342. If desired, however, the electrons could be provided in a direction that is coaxial with the gas flows as described, for example, in U.S. Patent No. 7,060,987. Introduced electrons may bombard analyte and reaction gas within chamber 316 as they pass to chamber outlet 342. In certain embodiments, an example electron source, of the form of electron source and accelerator 100 (see FIG. 3), may feed each of electron inlets 334. Electron inlets 334 may act as focusing lenses for electrons from accelerator 100 into chamber 316. To that end, electron inlets 334 may be formed in a conductive plate or portion thereof that may be electrically isolated from the remainder of the chamber 316. Electron inlets 334 may be positioned to allow electrons to pass through. A suitable voltage - for example in the range 0 to +400 V - could be applied to the plate, or the plate could be grounded. An electron collector 350 can be located opposite electron inlet 334 and may aid in accelerating and steering introduced electrons. A suitable voltage (e.g. 0-250 V) may be applied to electron collector 350. In some instances, an axial electron beam can be provided directly through aperture 342 with no gas in the chamber 316. The electron beam can enter into the reaction cell 390 into which flows analyte with carrier gas through opening 364 with or without a reaction gas. In some configurations, a reaction cell volume can confine the analyte entering the reaction cell 390 to a volume proximate to the ionized atoms from the chamber 316.

[0038] In certain embodiments, an illustration of an electron accelerator 100 is shown in more detail in FIG. 4, and takes the form of conductive helical coils 102, wound around an axis generally parallel to the travel axis of electrons within chamber 316 Coils 102 may be wound to form a void of about millimeter size (e.g., 0.5 mm to 3 mm or about 1mm), and at a winding density of about 10 turns per cm. As will be appreciated, any applied electrical current to coil 102, in turn also generates a magnetic field generally along the coil axis 104. A series resistance, or inherent resistance of coil 102, may limit the current flowing into coil 102. The magnitude of the magnetic field may be controlled by the applied current to coil 102, in manners appreciated by those of ordinary skill. Coil 102 may be formed of an electron emitting material - such as tungsten, or may be introduced from another source. Electrons are introduced along axis 104, and are focused as an electron beam, accelerated by the magnetic field, prior to introduction of the electrons into electron inlets 334 of chamber 316 Accelerated electrons may thus enter chamber 316, with an initial well defined velocity, to collide with analyte (and reaction gas traversing from chamber inlet 340 to chamber outlet 342.

[0039] In some instances, accelerator 100 may accelerate electrons by way of the Lorentz force - F = qv X B where F, v, and B represent the electron velocity vector, and the magnetic field vector, of the magnetic field generated by coils 102 and q represents a charge. Their vector cross product (scaled by the electron charge) determines the force on an electron. The resultant force F is perpendicular to both the velocity v of the particle with charge q, and the magnetic field vector B. As a consequence, the electron velocity is constrained to a direction along axis 104, or to circular motion centered around the axis of coil 102 with F acting as a centripetal force. Coil 102 would be wound about a straight axis. However, other geometries, in which coil 102 is wound about a non-linear axis may be possible - coil 102 could, for example, be wound around an arc, curve or the like.

[0040] Referring again to FIG. 3, the chamber outlet 342 can be formed in a. wall of chamber 316, and can act as a focusing lens 360. A further focusing lens 352 may be placed around chamber outlet 342. Ions exiting the chamber 316 at chamber outlet 342 may exit on an axis substantially similar to analyzer axis 320.

[0041] In some instances, a downstream reaction cell 370 can receive ionized gas (e.g. analyte and optionally reaction gas) from the chamber 316. A further gas may be introduced into the reaction cell 370 by way of (second) gas inlet 364. Further, a heating element 366 may heat the reaction cell 370 to provide additional thermal energy thereto. The reaction cell 370 may, for example, be heated to between 300 and 500 degrees Celsius.

[0042] In some configurations, the reaction cell 370 can take the form of a two stage reaction ceil having a first stage 380 including a rod set 382 arranged in a quadrupole about analyzer axis 320, and a second stage 390 including a rod set 392 further arranged in a quadrupole around axis 320, downstream of first stage 380, as for example described in US Patent No. 7,868,289, the contents of which are incorporated by reference herein. If desired, the rod set could instead be a hexapolar rod set or an octopolar rod set as shown in FIGS. 2B and 2C, respectively. Suitable voltages may be applied to the rod set 380 to provide a generally sinusoidal containment field about axis 320, and to guide ions along axis 320. Rod set 382 may, for example, act as a collision cell as is known in the art, which could have a pre-filter to aid ion focusing into the cell and/or to adjust ion energy. An axial field may also be applied to rod set 382. A suitable rod set is for example detailed in US Patent No. 7,868,289.

[0043] In embodiments having a twO-stage reaction cell, a reaction potential EJON may be applied and span between the first and second stages 380, 390, respectively, of the reaction cell 370 to select reaction energy. A low reaction potential can favor molecular ion formation while high energy can favor fragmentation. Reaction gas within the reaction cell 370 may interact with ionized analyte exiting chamber 316 This reaction may further selectively cause ionization of the ionized analyte exiting chamber outlet 342. Fragmented analyte may also exit chamber outlet 342 and be further ionized in the downstream reaction cell 370, by way of the reaction gas introduced to reaction cell 370 through the gas inlet 364.

[0044] In another embodiment, as for example mass analyzer 300' depicted in FIG. 5, chamber 316 (FIG 3) may be replaced with an electron impact chamber 314, allowing electron impact to be used in place of chemical ionization of analyte. A gas to be ionized may thus be introduced into chamber 314 without a reaction gas, by way of chamber inlet 340. Electron bombardment may ionize and/or fragment this gas introduced by way of chamber inlet 340. Again, introduced gas travels from chamber inlet 340 on one side of chamber 314 to the opposite side toward chamber outlet 342 and is ionized along its path. A charged element or repeller 336, having a suitable voltage applied thereto, may accelerate ions within chamber 314, as they travel toward chamber outlet 342.

[0045] Multiple electron inlets 334 are on a further, third side of chamber 314, and allow the introduction of electrons along a path generally transverse to the path between chamber inlet 340 and chamber outlet 342. Introduced electrons, may bombard gas as it passed from the chamber inlet 340 to chamber outlet 342, and aid in, or cause, its ionization.

[0046] An example electron source, of the form of electron source and accelerator 100, that can be used with the chamber 314 is again depicted in FIG. 4, and may feed each of electron inlets 334. Electron inlets 334 may act as focusing lenses for introduced electrons. An electron collector 350' located opposite electron inlets 334 may aid in accelerating and steering electrons. A suitable voltage (e.g. 0-250 V) may be applied to electron collector 350’.

[0047] Analyte exiting chamber outlet 342, may be focused by a first focusing lens 360 (e.g., formed in wall of chamber 316) and a further downstream focusing lens 352. A downstream reaction cell 370' receives ionized and/or fragmented gas from chamber 314. An interaction gas may be introduced into cell 370' by way of inlet 364'. Further, a heating element 366' may heat reaction cell 370'. Reaction cell 370' may take the form of a single stage reaction cell - that may for example be a collision cell - having a first stage 390' including a rod set 392' arranged in quadrupole about axis 320. The interaction gas in reaction cell 370' may interact with ionized gas exiting chamber 314. This reaction gas may further selectively cause interaction of the ionized gas exiting chamber outlet 342 and the gas introduced.

[0048] For illustration purposes only, example reactions for analyte A introduced into the chamber 314 are shown in FIG. 6. B/C are bombarding/reaction gases. Optionally, reaction cell 370' may be suitably pressurized to cool ions exiting cell 314. Inert gases such as nitrogen, argon or other gases at ambient temperature or below may be used.

[0049] In another, analyte gas may be introduced into chamber inlet 340 of chamber 314 of FIG. 5. Electron bombardment may cause the analyte gas to ionize and/or fragment. Ionized and/or fragmented analyte may exit chamber outlet 342, and further interact with gas introduced into reaction cell 370' by way of inlet 364'.

[0050] In one embodiment, analyte gas may be introduced into inlet 364' and a suitable chemical ionization or other analyte gas may be introduced into chamber 314 by way of chamber inlet 340. Example reactions for analyte A introduced into chamber 314, and analyte gases An I , An2 introduced into inlet 364' of reaction cell 370' are shown in FIG. 7. As is known in the art, other reaction pathways could include adduct formation and/or cluster ion formation. [0051 ] Resulting ionized analyte may be passed downstream along axis 320 for further analysis in downstream stages of the mass analyzer 300. It can thus be understood that a mass analyzer may, for example, include a mass filter/selector 58 (see FIG. 1) and/or other components downstream of the reaction cell 370. For example, the mass analyzer may comprise a downstream scanning mass analyzer, a magnetic sector analyzer (e.g., for use in single and double-focusing MS devices), a quadrupole mass analyzer, an ion trap analyzer (e.g., cyclotrons, quadrupole ions traps), time-of-flight analyzers (e.g., matrix-assisted laser desorbed ionization time of flight analyzers), and other suitable mass analyzers that can separate species with different mass-to-charge ratios. The mass analyzer may comprise two or more different downstream devices arranged in series, e.g., tandem MS/MS devices or triple quadrupole devices, to select and/or identify ions. A downstream detector can receive ions from the mass analyzer. Illustrative detectors include, but are not limited to, electron multipliers, Faraday cups, coated photographic plates, scintillation detectors, etc. and other suitable devices that will be selected by the person of ordinary skill in the art, given the benefit of this disclosure. Other mass analyzer components may also be included if desired.

[0052] The various voltages, gas pressures and the like that are used to operate the systems and mass analyzers can be controlled using one or more processors. For example, a processor can be present that can be part of the system or instrument or present in an associated device, e.g., computer, laptop, mobile device, etc. used with the instrument. For example, the processor can be used to control the voltages provided to the rods of the reaction cell, the pressures in the reaction cell, the type or amount of gas provided into the chamber 316 and can control the mass filter/selector and/or can be used by the detector. Such processes may be performed automatically by the processor without the need for user intervention or a user may enter parameters through user interface. For example, the processor can use signal intensities and fragment peaks along with one or more calibration curves to determine an identity and how much of each molecule is present in a sample. In certain configurations, the processor may be present in one or more computer systems and/or common hardware circuity including, for example, a microprocessor and/or suitable software for operating the system, e.g , to control the sample introduction device, ionization sources, mass analyzer, detector, etc. In some examples, the detection device itself may comprise its own respective processor, operating system and other features to permit detection of various molecules. The processor can be integral to the systems or may be present on one or more accessory boards, printed circuit boards or computers electrically coupled to the components of the system. The processor is typically electrically coupled to one or more memory units to receive data from the other components of the system and permit adjustment of the various system parameters as needed or desired. The processor may be part of a general-purpose computer such as those based on Unix, Intel PENTIUM-type processor, Motorola PowerPC, Sun UltraSPARC, Hewlett-Packard PA -RISC processors, or any other type of processor. One or more of any type computer system may be used according to various embodiments of the technology. Further, the system may be connected to a single computer or may be distributed among a plurality of computers attached by a communications network. It should be appreciated that other functions, including network communication, can be performed and the technology is not limited to having any particular function or set of functions. Various aspects may be implemented as specialized software executing in a general-purpose computer system. The computer system may include a processor connected to one or more memory devices, such as a disk drive, memory, or other device for storing data. Memory is typically used for storing programs, calibration curves, voltage values, pressure values and data values during operation of the systems. Components of the computer system may be coupled by an interconnection device, which may include one or more buses (e.g., between components that are integrated within a same machine) and/or a network (e.g., between components that reside on separate discrete machines). The interconnection device provides for communications (e.g., signals, data, instructions) to be exchanged between components of the system. The computer system typically can receive and/or issue commands within a processing time, e.g., a few milliseconds, a few microseconds or less, to permit rapid control of the system. For example, computer control can be implemented to control sample introduction, reaction cell rod voltages and/or frequencies provided to each rod, detector parameters, etc. The processor typically is electrically coupled to a power source which can, for example, be a direct current source, an alternating current source, a battery, a fuel cell or other power sources or combinations of power sources. The power source can be shared by the other components of the system. The system may also include one or more input devices, for example, a keyboard, mouse, trackball, microphone, touch screen, manual switch (e.g., override switch) and one or more output devices, for example, a printing device, display screen, speaker. In addition, the system may contain one or more communication interfaces that connect the computer system to a communication network (in addition or as an alternative to the interconnection device). The system may also include suitable circuitry to convert signals received from the various electrical devices present in the systems. Such circuitry can be present on a printed circuit board or may be present on a separate board or device that is electrically coupled to the printed circuit board through a suitable interface, e.g., a serial AT A interface, ISA interface, PCI interface or the like or through one or more wireless interfaces, e.g., Bluetooth, Wi-Fi, Near Field Communication or other wireless protocols and/or interfaces.

[0053] In certain embodiments, the storage system used in the systems described herein typically includes a computer readable and writeable nonvolatile recording medium in which codes of software can be stored that can be used by a program to be executed by the processor or information stored on or in the medium to be processed by the program. The medium may, for example, be a hard disk, solid state drive or flash memory . The progra or instructions to be executed by the processor may be located locally or remotely and can be retrieved by the processor by way of an interconnection mechanism, a communication network or other means as desired. Typically, in operation, the processor causes data to be read from the nonvolatile recording medium into another memory' that allows for faster access to the information by the processor than does the medium. This memory is typically a volatile, random access memory such as a dynamic random access memory' (DRAM) or static memory (SRAM). It may be located in the storage system or in the memory system. The processor generally manipulates the data within the integrated circuit memory and then copies the data to the medium after processing is completed. A variety of mechanisms are known for managing data movement between the medium and the integrated circuit memory' element and the technology is not limited thereto. The technology is also not limited to a particular memory system or storage system. In certain embodiments, the system may also include specially-programmed, special-purpose hardware, for example, an application-specific integrated circuit (ASIC) or a field programmable gate array (FPGA). Aspects of the technology may be implemented in software, hardware or firmware, or any combination thereof. Further, such methods, acts, systems, system elements and components thereof may be implemented as part of the systems described above or as an independent component. Although specific systems are described by way of example as one type of system upon which various aspects of the technology may be practiced, it should be appreciated that aspects are not limited to being implemented on the described system. Various aspects may be practiced on one or more systems having a different architecture or components. The system may comprise a general-purpose computer system that is programmable using a high-level computer programming language. The systems may be also implemented using specially programmed, special purpose hardware. In the systems, the processor is typically a commercially available processor such as the well-known Pentium class processors available from the Intel Corporation. Many other processors are also commercially available. Such a processor usually executes an operating system which may be, for example, the Windows 95, Window's 98, Windows NT, Windows 2000 (Windows ME), Windows XP, Windows Vista, Windows 7, Windows 8 or Windows 10 operating systems available from the Microsoft Corporation, MAC OS X, e.g., Snow Leopard, Lion, Mountain Lion or other versions available from Apple, the Solaris operating system available from Sun Microsystems, or UNIX or Linux operating systems available from various sources. Many other operating systems may be used, and in certain embodiments a simple set of commands or instructions may function as the operating system. Further, the processor can be designed as a quantum processor designed to perform one or more functions using one or more qubits.

[0054] In certain examples, the processor and operating system may together define a platform for which application programs in high-level programming languages may be written. It should be understood that the technology is not limited to a particular system platform, processor, operating system, or network. Also, it should be apparent to those skilled in the art, given the benefit of this disclosure, that the present technology is not limited to a specific programming language or computer system. Further, it should be appreciated that other appropriate programming languages and other appropriate systems could also be used. In certain examples, the hardware or software can be configured to implement cognitive architecture, neural networks or other suitable implementations. If desired, one or more portions of the computer system may be distributed across one or more computer systems coupl ed to a communications network. These computer systems also may be general-purpose computer systems. For example, various aspects may be distributed among one or more computer systems configured to provide a service (e.g., servers) to one or more client computers, or to perform an overall task as part of a distributed system. For example, various aspects may be performed on a client-server or multi-tier system that includes components distributed among one or more server systems that perform various functions according to various embodiments. These components may be executable, intermediate (e.g., IL) or interpreted (e.g., Java) code which communicate over a communication network (e.g., the Internet) using a communication protocol (e.g., TCP/IP). It should also be appreciated that the technology is not limited to executing on any particular system or group of systems. Also, it should be appreciated that the technology is not limited to any particular distributed architecture, network, or communication protocol.

[0055] In some instances, various embodiments may be programmed using an object-oriented programming language, such as, for example, SQL, SmallTalk, Basic, Java, Javascript, PHP, C++, Ada, Python, i OS/Swift, Ruby on Rails or C# (C-Sharp). Other object-oriented programming languages may also be used. Alternatively, functional, scripting, and/or logical programming languages may be used. Various configurations may be implemented in a non- programmed environment (e.g., documents created in HTML, XML or other format that, when viewed in a window of a browser program, render aspects of a graphical -user interface (GUI) or perform other functions). Certain configurations may be implemented as programmed or non- programmed elements, or any combination thereof. In some instances, the systems may comprise a remote interface such as those present on a mobile device, tablet, laptop computer or other portable devices which can communicate through a wired or wireless interlace and permit operation of the systems remotely as desired.

[0056] In certain examples, the processor may also comprise or have access to a database of information about molecules, their ionization or fragmentation patterns, and the like, which can include molecular weights, mass-to-charge ratios and other common information. The instructions stored in the memory can execute a software module or control routine for the system, which in effect can provide a controllable model of the system. The processor can use information accessed from the database together with one or software modules executed in the processor to determine control parameters or values for different components of the systems, e.g., different rod voltages, different pressures, etc. Using input interlaces to receive control instructions and output interfaces linked to different system components in the system, the processor can perform active control over the system. For example, the processor can control the detector device, sample introduction devices, ion sources and other components of the system.

[0057] Certain specific examples are described to illustrate some of the uses of the technology described herein.

[0058] Example 1

[0059] A sample comprising argon gas and volatile organic compounds can be introduced into the chamber 316 through the chamber inlet 340 of the mass analyzer 300. Depending on the voltages and pressures used, the source can provide intact molecular ions or fragment ions to a downstream reaction cell 370.

[0060] Example 2

[0061] In another mode of operating the mass analyzer, argon gas by itself can be provided to the chamber 316 (e.g., via chamber inlet 340) without any analyte. The produced argon ion beam with an energy distribution of about 12eV can be guided into the reaction cell 370. Analyte vapor can then be introduced into the reaction cell (e.g., via inlet 364) at a pressure of 5 to 10 milliTorr. Analyte molecules with an ionization potential below 12eV on collision with an argon ion are ionized and remain as an intact molecular ion. These ions can be mass resolved using a downstream quadrupole mass filter or other mass filter.

[0062] Example 3

[0063] A similar set up as used in Example 2 but with additional excitation of the argon ions prior to being provided to the downstream reaction cell 370 can be used. The argon ions can be energetically excited to about 40eV before entering into the reaction cell 370 where they are collided with sample molecule.

[0064] Example 4

[0065] The conditions used in the chamber 316 can be optimized to favor or produce intact molecular ions. The energy of the ions produced in the chamber 316 can be adjusted to about 3 eV before being provided to the reaction cell . Ammonia reagent gas can be added into the reaction cell at a desired pressure, e.g., 15 milliTorr. Since the proton affinity of ammonia (854 KJ/mol) is high, collisions with molecular ion can result in the formation of ammonia adducts to molecular ions. These ions can be resolved using a downstream quadrupole mass filter or other mass filter.

[0066] When introducing elements of the examples disclosed herein, the articles "a,”“an,”“the” and“said” are intended to mean that there are one or more of the elements. The terms “comprising,”“including” and“having” are intended to be open-ended and mean that there may be additional elements other than the listed elements. It will be recognized by the person of ordinary skill in the art, given the benefit of this disclosure, that various components of the examples can be interchanged or substituted with various components in other examples.

[0067] Although certain aspects, examples and embodiments have been described above, it will be recognized by the person of ordinary skill in the art, given the benefit of this disclosure, that additions, substitutions, modifications, and alterations of the disclosed illustrative aspects, examples and embodiments are possible.

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