Inductively coupled plasma-based atomic analysis system and method

Abstract

Inductively coupled plasma (ICP) analyzers use an ICP torch to generate plasma in which the sample is atomized and ionized. Analysis of the atomic ions can be performed using atomic analysis, such as mass spectrometry (MS) or atomic emission spectrometry (AES). Particle-based ICP analysis involves analyzing particles (e.g., cells, magnetic beads, or laser ablation plumes) by atomizing and ionizing them in an ICP torch chamber followed by atomic analysis. In mass cytometry, the mass tags of the particles are analyzed using mass spectrometry, such as ICP-MS. The systems and methods of this application include one or more of the following: a removable ICP torch holder assembly, an external ignition device, an ICP induction coil including annular fins, a particle-suspended sample introduction jet, and its ICP analyzer.

Description

[0001] This application is a divisional application of Chinese invention patent application No. 202180077921.6, filed on September 9, 2021, entitled "Atomic Analysis System and Method Based on Inductively Coupled Plasma". Cross-references to related applications

[0002] This application claims the benefit of priority to U.S. Provisional Application No. 63 / 080,672, filed September 18, 2020; U.S. Provisional Application No. 63 / 081,172, filed September 21, 2020; and U.S. Provisional Application No. 63 / 184,521, filed May 5, 2021, the entire contents of all such applications are incorporated herein by reference for all purposes. Technical Field

[0003] This application relates to systems and methods for inductively coupled plasma (ICP) analysis, including those for mass cytometry. Background Technology

[0004] Inductively coupled plasma (ICP) analyzers use an ICP torch to generate plasma in which the sample is nebulized and ionized. Analysis of the atomic ions can be performed using atomic analysis, such as mass spectrometry (MS) or atomic emission spectrometry (AES). Particle-based ICP analysis involves analyzing particles (e.g., cells, magnetic beads, or laser ablation plumes) by nebulizing and ionizing them in an ICP torch followed by atomic analysis. In mass cytometry, the mass tag of the particles is analyzed using mass spectrometry, such as via ICP-MS. Summary of the Invention

[0005] The systems and methods of this application include one or more of the following: a detachable ICP torch holder assembly, an external ignition device including an ICP induction coil with annular fins, a sample introduction fluidics for particulate suspension, and an ICP analyzer thereof. Attached Figure Description

[0006] The instruction manual refers to the following figures, in which the same reference numerals are used in different figures to indicate the same or similar parts.

[0007] Figure 1This is a schematic diagram of the standard suspension mass spectrometry flow cytometry workflow.

[0008] Figure 2 This is a schematic diagram of a standard suspension mass spectrometry flow cytometry system.

[0009] Figure 3 This is a schematic diagram of a standard ICP torch.

[0010] Figure 4 This is a schematic diagram of an exemplary ICP torch box for this subject application.

[0011] Figure 5 yes Figure 4 Exploded view of the ICP torch box and the upstream spray chamber.

[0012] Figure 6 yes Figure 4 A cross-sectional view of the ICP torch box.

[0013] Figure 7 This is a schematic diagram of an exemplary torch holder component of this subject application.

[0014] Figure 8 yes Figure 7 Exploded view of the torch holder assembly.

[0015] Figure 9 This is a circuit diagram of an exemplary external ignition device for this subject application.

[0016] Figure 10 This is a schematic diagram of an exemplary sample ring of the sample introduction device of this subject application.

[0017] Figure 11 It is used for Figure 10 A schematic diagram of the stirrer for the sample ring.

[0018] Figure 12 This is a schematic diagram of the sample introduction jet during sample loading.

[0019] Figure 13 This is a schematic diagram of the sample introduction jet during sample injection.

[0020] Figure 14 yes Figure 7 A schematic diagram of an exemplary cross-section of the torch holder assembly. Detailed Implementation

[0021] Certain aspects and features of this disclosure relate to systems and methods for inductively coupled plasma (ICP) analysis, including for mass spectrometry flow cytometry techniques as further described herein.

[0022] Inductively Coupled Plasma (ICP) Systems, Samples, and Methods Inductively coupled plasma (ICP) is a plasma source in which energy is supplied by an electric current generated by electromagnetic induction (i.e., by a time-varying magnetic field). Industrial-scale applications of ICP include micromachining (e.g., etching or cleaning) or waste disposal. Such applications may not generate plasma in an ICP torch, may not use ICP induction coils, may not operate under atmospheric conditions, and / or may not be at a scale suitable for atomic analysis of samples (e.g., the generated plasma may be at least an order of magnitude larger than that of an ICP analyzer). Therefore, the physical characteristics of industrial ICP differ from those of ICP analysis using an ICP torch and may be outside the scope of several aspects of this disclosure. Systems and methods using ICP torches, such as ICP analyzers, are discussed herein.

[0023] In John Wiley & Sons' 1998 book, written by Akbar Montaser Inductively coupled plasma mass spectrometry An overview of ICP mass spectrometers (ICP-MS) is provided, including a description of eddy currents and ignition. Similar considerations are given for sample introduction and ICP torches in atomic emission spectrometry (AES), which is also within the scope of this application. As used herein, atomic spectroscopy is the same as atomic analysis and may include atomic mass spectrometry (e.g., ICP-MS) or ICP-AES. Suitable samples include biological samples, geological samples, and articles. In some respects, biological samples may be fluids comprising biomolecules and / or contaminants (e.g., metallic toxins), or particles (e.g., cells (e.g., in suspension or in tissue sections), or magnetic beads (e.g., for the determination of biomolecules)).

[0024] Mass Flow Cytometry System and Method This subject application includes ICP torch systems and methods for mass spectrometry flow cytometry, which detects mass tags in cells or magnetic beads using mass spectrometry analysis. Mass spectrometry flow cytometry is discussed in U.S. Patent Publications US20050218319, US20160195466, and US20190317082, the entire contents of which are incorporated herein by reference. Mass spectrometry flow cytometry can be used for suspended particles (e.g., cells or magnetic beads) or particles generated from solid samples (e.g., laser ablation plumes generated from tissue sections). In suspension mass spectrometry flow cytometry, a suspension of cells or magnetic beads including mass tags is analyzed using atomic mass spectrometry analysis. Imaging mass spectrometry flow cytometry performed by laser ablation (LA) ICP-MS is described in U.S. Patent Publications US20160056031 and US20140287953, which are incorporated herein by reference. Giesen, Charlotte et al. in "Highly multiplexed imaging of tumor tissues with subcellular resolution by mass cytometry" ( Nature methods Imaging mass cytometry performed by LA-ICP-MS is also described in 11.4 (2014):417-422.

[0025] Quality tags can be metallic tags that bind to an affinity reagent (e.g., an antibody, oligonucleotide, avidin, or other biomolecule that specifically binds to a target biomolecule). For example, metal nanoparticles or metal chelate polymers can be attached (e.g., covalently bound) to an affinity reagent, which is then applied to a sample. Suitable quality tags are described in U.S. Patent Publications US20040072250 and US20080003616, the entire contents of which are incorporated herein by reference. In some aspects, some quality tags (e.g., metals containing pharmaceutical or histochemical stains) do not bind to the affinity reagent.

[0026] Figure 1 This is a schematic diagram of the standard mass spectrometry flow cytometry workflow. Figure 2 This is a schematic diagram of a standard mass cytometry system used in this workflow. A suspension mass cytometry workflow may include labeling cells using mass tags (see [link to documentation]). Figure 1Cells labeled with labeled antibodies are displayed on the upper left of the sample container (e.g., cells and / or magnetic beads). Particles (e.g., cells and / or magnetic beads) are transferred from a sample container (e.g., a tube) held by a sample holder, through a nebulizer, and into a spray chamber via a sample introduction jet. The spray chamber causes a carrier gas (i.e., an aerosol spray) to surround droplets exiting from the nebulizer. Unlike many other spray chambers, the spray chamber of a suspension mass cytometry system delivers particles into an ICP torch chamber, rather than to a waste outlet. Exemplary spray chambers suitable for mass cytometry include those discussed in U.S. Patent Publication US20130181126, the entire contents of which are incorporated herein by reference. As further described herein, the ICP torch chamber includes an ICP torch. Particles enter the ICP plasma of the ICP torch, where they are atomized and ionized. A vacuum pressure differential guides ionized atoms from the plasma through a sample cone (and one or more additional cones) into a mass analyzer. In some cases, the ion optics of the mass analyzer can be configured to filter ions. For example, when the mass tag includes heavy metals (e.g., transition elements or lanthanides) or their isotopes, a mass filter (e.g., a deflector or an RF quadrupole) can be configured as a high-pass mass filter to remove ions below a certain mass. Since the argon dimers present in ICP plasma are typically 80 amu (atomic mass unit), a high-pass mass filter can remove ions at a cutoff point of at least 80 amu. Such a high-pass filter can be particularly useful when the mass analyzer includes a time-of-flight detector (i.e., TOF-MS). Suitable mass analyzers include synchronous mass analyzers, such as TOF-MS or sector magnetic field MS. In some respects, the mass analyzer can be another analyzer such as a quadrupole MS (QMS). The ions of the mass tag detected by the mass analyzer indicate the presence of an affinity target that specifically binds to that mass tag. Because of the relatively small crosstalk between multiple mass channels in mass cytometry compared to the detection of fluorescent markers (which exhibit spectral overlap), a large number of mass tags can be distinguished in individual particles. In some respects, multiple distinguishable mass tags (e.g., at least 20, at least 30, or at least 40 mass tags) can be detected in a single-cell event.

[0027] In some aspects, the system may include a filter located at the inlet of the sprayer. This filter may allow single cells to pass through but may prevent cell clusters from entering the sprayer, for example, to reduce clogging at the sprayer (e.g., at the tip of the sprayer). The filter may include a mesh, such as a nylon mesh, or any material suitable for cell filtration. The filter may allow particles smaller than the inner diameter of the sprayer's channel (e.g., less than 80% or 50% of the inner diameter of the channel). For example, the inner diameter of the sprayer may be 200 micrometers or less, 150 micrometers or less, or 100 micrometers or less, for example, between 50 and 150 micrometers. The filter's cutoff point may be greater than 25 micrometers, greater than 50 micrometers, greater than 80 micrometers, or greater than 100 micrometers, allowing particles below the cutoff point to enter the sprayer. The filter may be located at... Figure 2 The interface between the nebulizer and the sample introduction jet is shown. A filter may be located near the sealing connection between the sample ring and the nebulizer for the sample introduction jet. The inner diameter of the sample ring may be larger than the channel inner diameter of the nebulizer, for example, at least 2 times or at least 5 times larger. For example, the inner diameter of the sample ring may be at least 0.2 mm, at least 0.5 mm, at least 1 mm, or at least 2 mm. The sealing connection and / or filter may be removed from the nebulizer, for example, to replace the filter.

[0028] Although the workflow and system of mass flow cytometry have been described above, it should be understood that sampling systems such as laser ablation systems can replace sample introduction jets in order to deliver laser ablation plume particles to the mass flow cytometer.

[0029] ICP torch box Typically, an ICP torch box includes an ICP torch body and an ICP induction coil positioned around an outer tube of the torch body. Optionally, the ICP torch box may also include an ignition device and / or a gas supply manifold. The ICP torch body may include at least an inner tube and an outer tube, although the inner tube may be an intermediate tube positioned around the innermost tube. Where the inner and outer tubes are separable, they may be described as belonging to separate inner and outer tube bodies, respectively. Embodiments of the invention include an ICP torch box that incorporates specific equipment and methods using any of the various aspects described herein, such as ICP torch assemblies (e.g., a removable ICP torch box holder assembly), external ignition devices, ICP induction coils, and / or gas supply manifolds, etc.

[0030] like Figure 3 As shown, an exemplary torch in the art can provide a vortex with a single external gas (i.e., plasma gas) inlet (or, in some cases, two inlets). This external gas inlet can extend from the torch tube and can be made of the same material as the torch tube.

[0031] Figure 4 An exemplary torch box of this subject application is shown. Figure 4 An external ignition device comprising a circuit board including two high-voltage transformers that provide AC output voltage to two electrodes located outside the outer torch tube is depicted. Figure 5 An exploded view of the rest of the torch box is provided. Figure 5 The left side shows an ICP induction coil including annular fins, and a gas supply manifold that holds the removable torch holder assembly. The spray chamber is shown upstream of the torch box and includes a syringe extending into the inner tube of the torch assembly.

[0032] Figure 6 This is a cross-sectional view of the torch assembly. Most of the components extend radially around the axis of the injector and torch. The annular fins of the ICP induction coil are shown as having a thickness less than its length. The torch retainer is shown positioned around the inner and outer torch bodies and located within the gas supply manifold. As further discussed herein, gas flows from the manifold through the torch retainer and into the inner or outer torch.

[0033] Figure 7 It shows Figure 5 A close-up view of the torch retainer assembly. Figure 8 An exploded view of an exemplary torch holder assembly is shown, which includes an inner torch body and an outer torch body. The inner torch body includes an inner tube coupled to an inner tube base, and the outer torch body includes an outer tube coupled to an outer tube base. The inner and outer bases are received by a torch holder and are releasable from the torch holder and from their respective tubes.

[0034] As described in one or more aspects herein, an ICP torch box may include a torch retainer assembly that provides eddy current and / or is removable. For example, as described herein, the outer torch body and optionally the inner torch body can be removed from the torch retainer. Alternatively or additionally, the outer tube can be removed from the outer tube base, and / or the inner tube can be removed from the inner tube base. Alternatively or additionally, the torch box retainer assembly can be easily removed from the torch box (e.g., by twisting and / or pulling back), and can be disassembled without removing the ignition electrode from the outer tube.

[0035] As described in one or more aspects herein, the ICP torch box includes an external ignition device. This external ignition device may be located outside the outer tube and upstream of the ICP coil. The external ignition device may include two electrodes located on opposite sides of the outer torch tube. The mechanism of external ignition may be by discharge, such as dielectric barrier discharge as further described herein. In some aspects, the external ignition device enables the design and operation of a detachable torch, particularly for ICP-MS analysis in which the ignition electrodes are not suitable to be located downstream of the torch. External ignition devices of any aspect (or aspects) discussed herein may be combined within the ICP torch box with torch holder assemblies of any aspect (or aspects) discussed herein.

[0036] In some respects, the ICP torch box includes the ICP induction coil of this subject application. The ICP induction coil of any aspect (or aspects) discussed herein may be combined in the ICP torch box with the torch holder assembly of any aspect (or aspects) discussed herein, and / or with the external ignition electrode of any aspect (or aspects) discussed herein.

[0037] Further optionally, any of the above-described ICP torch boxes may also include a gas supply manifold of any aspect (or multiple aspects) described herein.

[0038] In some respects, the spray chamber and / or syringe (the tube extending from the spray chamber) can be described as part of the torch chamber, although the spray chamber can be described as part of the sample introduction system of the torch chamber. Typically, the syringe of the spray chamber coaxially delivers the sample (e.g., atomized particles) into the inner tube (i.e., the innermost tube) of the ICP torch chamber and can be inserted into the inner tube.

[0039] In some respects, the ICP torch box is part of the ICP analyzer. For example, the sample cone of the mass analyzer can be positioned to receive ionized atoms generated from the sample by the ICP plasma from the ICP torch. In this case, the external ignition device described herein allows for a detachable design of the torch holder assembly described herein.

[0040] Several aspects include an inductively coupled plasma (ICP) torch box comprising: a removable ICP torch holder assembly, an external ignition device, and / or an ICP induction coil, the external ignition device igniting the plasma via a dielectric barrier discharge, the ICP induction coil comprising annular fins. The ICP induction coil may be 3D printed.

[0041] In one specific embodiment, an inductively coupled plasma (ICP) torch box includes: (1) A detachable inductively coupled plasma (ICP) torch holder assembly, the ICP torch holder assembly comprising: an inner torch body, an outer torch body and a torch holder, the inner torch body comprising an inner tube connected to an inner tube base, the outer torch body comprising an outer tube connected to an outer tube base, and the torch holder holding a detachable inner torch base and a detachable outer torch base. (2) An ICP induction coil positioned around an outer tube, the ICP induction coil comprising: a cylindrical coil, wherein the cylindrical coil includes annular fins, and wherein the annular fins are continuous within at least one-eighth of a turn of the cylindrical coil, and wherein the ICP induction coil primarily comprises a metal or alloy having a lower oxidation rate than copper during operation; and (3) Ignition device for igniting plasma in an inductively coupled plasma (ICP) torch, the ignition device comprising: a circuit including: an oscillator, a first high-voltage transformer coupled to a first electrode, and a second high-voltage transformer coupled to a second electrode, wherein the ignition device is configured to ignite the plasma by dielectric barrier discharge, and wherein the first electrode and the second electrode are positioned on opposite sides of an outer tube and within 5 mm of the outer tube.

[0042] torch retainer assembly As exemplified by the various aspects discussed below, the various embodiments of this subject application relate to a plurality of torch components and their use. These aspects can be combined in any feasible combination.

[0043] Several aspects of this subject torch assembly include a removable ICP torch retainer assembly (e.g., an ICP torch housing including the torch assembly) and its method of use. The removable torch can be removed from the torch housing (e.g., from the gas supply manifold of the torch housing) by pulling the torch retainer back (i.e., in the opposite direction to the direction in which gas will flow through the torch during operation). In some aspects, the removable torch can be secured within the ICP torch housing by the gas source manifold, and the removable torch can be unscrewed before removing the torch assembly (e.g., to unscrew the pin of the removable torch from its locked position in the gas supply manifold). In some aspects, the ICP torch housing includes an external ignition electrode as described herein, such that no electrode is inserted into the outer tube of the ICP torch assembly, thereby simplifying the removal of the torch assembly from the torch housing (e.g., allowing removal in a single step). This removal facilitates maintenance of the ICP torch (e.g., cleaning or replacement of one or more torch tubes).

[0044] Alternatively or additionally, the torch retainer of the removable ICP torch assembly can be configured to at least accommodate (and thus allow removal of) an outer torch base coupled to an outer tube. Similarly, the torch retainer can be configured to accommodate an inner torch base coupled to an inner tube. Alternatively, the torch retainer can be permanently attached (e.g., machined as a single component or adhered together) to the inner tube and / or coupled to an inner tube base of the inner tube. The torch assembly can be configured to coaxially align the inner and outer tubes. O-rings can be used to provide an airtight seal between the inner and / or outer tube bases and the torch retainer. In some aspects, the inner and outer tube bases can be directly and permanently referenced to each other (e.g., machined as a single component or adhered together), or can be configured to be directly connected to each other by fasteners, such as the threads of one of the inner and outer torch bases being screwed into the other. The inner and outer bases, directly referenced to each other, can be removed from the torch retainer as a single unit.

[0045] The inner and / or outer tubes described in various aspects herein may be made of materials such as glass, quartz, or ceramic. The inner tube base and / or outer tube base described in various aspects herein may be made of different materials, such as metals (e.g., aluminum alloys).

[0046] In some respects, the outer torch can be removed from the outer torch base for maintenance (e.g., cleaning or replacement). The outer torch may be damaged during operation due to breakage, heating, or deposits. The outer torch can be less expensive than the outer torch base, and this removable configuration reduces maintenance costs. Similarly, in some respects, the outer torch can be removed from the outer torch base for maintenance (e.g., cleaning or replacement). The outer torch may be damaged during operation due to breakage, heating, or deposits. The outer torch can be less expensive than the outer torch base, and this removable configuration reduces maintenance costs.

[0047] The torch assembly can be configured to allow external gas (also known as plasma gas) to enter the outer tube of the torch assembly.

[0048] Previously, one orifice, and sometimes two orifices, have been used to introduce eddies. These orifices are typically defined by a tube of the same material as the outer torch tube (e.g., glass, quartz, or ceramic), and can be located on one side of the torch tube. This design can complicate the removal of the torch assembly (e.g., from the gas supply manifold) and / or the removal of the outer torch tube from the torch holder of the torch assembly. Furthermore, this design may not be able to accommodate several such orifices.

[0049] In some aspects, the outer torch body of the torch assembly may include a plurality of holes (e.g., three or more holes, such as six holes) positioned and oriented to guide external gas into an annular region between the inner and outer tubes and to generate vortices in this region. While these holes may be radially symmetrical, they may be diagonally oriented (i.e., may not extend radially outward from the axis of the cylinder defined by the outer tube). These holes may be located in the outer torch base of the outer torch body. With the outer and inner torch bodies held by torch holders (e.g., at their respective bases), these holes in the outer torch base may allow fluid communication from the external gas inlet of the torch holder to the annular region defined between the inner and outer tubes. Accordingly, the torch holder may be held by a gas supply manifold, providing fluid communication between the external gas inlet (e.g., a port) of the gas supply manifold and the external gas inlet of the torch holder. In some aspects, the outer torch base, torch holder, and gas supply manifold are all primarily constructed of metal.

[0050] Alternatively or additionally, the torch retainer may provide fluid communication to deliver an internal gas (also known as an auxiliary gas) from the supply manifold to the inner torch body. Alternatively or additionally, the supply manifold may provide fluid communication to allow a carrier gas (also known as a spray chamber gas or aerosol gas) to flow from a carrier gas inlet (e.g., a port) of the supply manifold into the spray chamber. Thus, the supply manifold may have separate ports for one or more of the carrier gas, internal gas, and external gas. Each port may be coupled to a gas source, such as a gas source including argon and / or helium. In some aspects, the external gas may include argon. Alternatively, the external gas may include a gas other than argon or helium, such as nitrogen.

[0051] The aforementioned fluid connectivity allows the conduit to be positioned away from the torch retainer assembly (e.g., not directly connected to the torch retainer or outer torch body), making it easier to remove the torch retainer from the torch housing (e.g., from the torch housing's gas supply manifold).

[0052] In some respects, a detachable ICP torch holder assembly includes: an inner torch body, an outer torch body, and a torch holder, the inner torch body including an inner tube coupled to an inner tube base, the outer torch body including an outer tube coupled to an outer tube base, and the torch holder being configured to receive the inner torch base and the outer torch base, wherein, with the torch holder holding the inner torch base and the outer torch base, the inner tube and the outer tube define an annular region.

[0053] In some respects, the outer tube is removed from the outer tube base, and / or the inner tube is removed from the inner tube base.

[0054] The torch holder may have an external gas inlet, which is in fluid communication with the annular region. The outer tube base may define three or more orifices (e.g., six orifices) positioned to provide fluid communication between the external gas inlet and the annular region, and wherein the orifices are oriented to generate vortices. These orifices may be positioned close to the plasma such that the vortices do not dissipate and only a low external gas flow is required. For example, these orifices may be located within 2.5 cm of the outlet of the inner torch tube. The outer tube may not include a cone. Alternatively, the outer tube defines a cone, wherein the cone accelerates the external gas toward the plasma.

[0055] The inner tube base and the outer tube base can be removed from the torch retainer separately, or they can be referenced to each other (e.g., where the inner tube base and the outer tube base are permanently engaged with each other, where the inner torch base and the outer torch base are configured to be connected by fasteners such as threads).

[0056] The torch retainer includes a heat-conducting element positioned to heat the syringe to reduce deposits and / or blockages in the syringe.

[0057] In some respects, metals or alloys such as aluminum alloys are the primary materials for the torch holder. The outer tube does not include holes for extending the electrodes into it.

[0058] The torch housing may also include a gas supply manifold configured to receive a torch retainer. For example, the torch retainer may include a pin for aligning the torch retainer in position within the gas supply manifold, and wherein twisting the torch retainer allows removal of the torch retainer from the gas supply manifold. The torch retainer may define an external gas inlet, wherein the external gas inlet is in fluid communication with an annular region and with an external gas flow region of the gas supply manifold.

[0059] In some respects, an inductively coupled plasma (ICP) torch assembly includes: an inner tube, an outer tube, and an outer tube base coupled to the outer tube, wherein the inner and outer tubes define an annular region, and wherein the outer tube base defines three or more orifices positioned to allow external gas to enter the annular region, and wherein the three or more orifices are oriented to generate eddies.

[0060] Figure 9This is a schematic cross-sectional view of an exemplary torch holder assembly. As shown, the torch holder holds the torch base. The torch base can be a single component (e.g., a continuous plastic piece, or an inner and outer base permanently fixed to each other), or it can include separate inner and outer bases that can be separated from each other. The separable inner base from the outer base allows the inner torch body (inner base and inner tube) to be separated from the outer torch body for cleaning or replacement. For example, the outer torch may require more regular maintenance due to heat or deposits from materials exposed to the plasma.

[0061] For example Figure 9 As shown, the torch base may include one or more external gas inlets (e.g., at least two, at least three, at least four (e.g., six, eight, or ten external gas inlets)), each external gas inlet communicating with a separate orifice that guides external gas from a supply manifold (not shown) into the annular space between the inner and outer tubes of the torch retainer assembly. These orifices may be positioned directly adjacent to the outer tube, allowing external gas to be directly injected into the space between the inner and outer tubes. These orifices may be angled to provide vortex flow.

[0062] In some respects, the outer and inner tubes can be permanently attached to the torch base (e.g., the outer tube is attached to the outer torch base, and the inner tube is attached to the inner torch base). For example, the outer tube can be attached to the outer torch base by an adhesive (e.g., heat-resistant glue). The gap between the outer wall of the outer tube and the torch base (e.g., the outer torch base) allows the adhesive to bond the two together and allows the outer tube and / or adhesive to expand during heating (e.g., when the torch is operated). In some respects, the width of this gap can be greater than 0.2 mm, greater than 0.5 mm, or greater than 1 mm, for example, about 2 mm. This permanent connection and / or gap allows the outer tube to be attached to the torch base without an interference fit. The length of the overlap area between the outer tube and the torch base can be short, such that the vortex of external gas injected into the outer torch through the orifice has a small distance, during which time the vortex can dissipate or decrease before the torch sustains the plasma. This length can be, for example, less than 10 mm or less than 5 mm.

[0063] External ignition Although the ICP induction coil sustains the plasma in the ICP torch, the ignition electrode (e.g., a Tesla coil electrode) is typically employed to ignite the plasma via a process described as an arc discharge or spark. The spark from the ignition electrode can be generated using a conductive element (e.g., a grounded conductive element) located near the plasma (e.g., an ICP coil). The ICP torch can operate at atmospheric pressure (e.g., between 0.9 and 1.1 atm (standard atmospheric pressure)). In ICP-AES, because the plasma is analyzed directly by spectroscopic analysis, the electrode can be located downstream of the outer torch tube (i.e., downstream in terms of the gas flow through the torch). However, in ICP-MS, because the ignition electrode can generate a spark with the sample cone rather than with any conductive element near where the plasma will be held, the sample cone, positioned near the outlet of the outer tube to receive ionized atoms into the mass spectrometer, can prevent the ignition electrode downstream of the torch. This problem has previously been solved by inserting the ignition electrode through the outer torch tube (e.g., downstream of the ICP coil, as described in U.S. Patent No. US4766287). However, inserting electrodes through the torch body may prevent the torch assembly from being easily removed for maintenance (e.g., cleaning or replacement of one or more torch tubes). Therefore, in some respects, the external ignition devices and methods of this subject matter application can be combined with the detachable torch further described herein.

[0064] External ignition allows the detachable torch to have a metal assembly / holder for insertion, as well as a gas supply section. The inventors discovered that mass spectrometry flow cytometry ignition methods with internal spark electrodes are unusable due to the proximity of the metal portions in the torch assembly; the spark would fly back to the torch base instead of reaching the sampling interface. The external electrode arrangement positions the electrodes in an unobstructed location while still allowing the discharge to occur close to the plasma space. Early successful experiments used a single electrode, with the discharge entering the metal base of the torch tube. AC pulses generated using a Tesla coil outside the torch are also sufficient to create plasma. The inventors also identified a higher-energy, high-voltage AC generator with symmetrical output. This provides reliable ignition and repeatability for ease of fabrication.

[0065] An external ignition device ignites the plasma in an inductively coupled plasma (ICP) torch by discharging (e.g., by discharging through an electrostatic barrier). This external ignition device can be configured to supply AC current to at least one electrode.

[0066] Figure 9The exemplary external breakdown circuit shown includes an oscillator that generates an AC signal at a frequency of approximately 30 kHz, which is varied within a range of + / - 2 kHz near the median by a low-frequency (100 Hz) modulator. The modulated signal is then amplified in a power bridge circuit driving two output transformers T1 and T2. Transformers T1 and T2 are connected in the circuit with opposite polarities, such that their respective output voltages are out of phase (180 degrees out of phase with each other). Transformers T1 and T2 operate close to their natural resonance, effectively boosting the voltage to 30 kV, which is then applied to the ignition electrode attached to the torch assembly. It is noteworthy that transformers with frequencies other than 30 kV (e.g., other frequencies in the range of 1 kV to 100 kV) can be paired with oscillators operating at similar frequencies. The intermediate frequency of the oscillator is chosen to be 30 kHz, for example, an approximate resonant frequency of the step-up transformers T1 and T2 (which are in principle identical but may be affected by manufacturing tolerances).

[0067] Due to manufacturing tolerances, the actual resonant frequency of the transformer may not be as precise as specified at 30 kHz. However, it is important to drive the transformer with an AC current at its actual resonant frequency in order to obtain the maximum output voltage for ignition.

[0068] To ensure the transformer's resonant frequency is met, a 100 Hz modulator is used. This modulator applies a triangular ramp signal to the control input of a 30 kHz oscillator, causing the oscillator's frequency to continuously sweep between approximately 28 kHz and 32 kHz. Whenever the transformer's inherent resonant frequency is instantaneously matched, the transformer's output voltage applied to the ignition electrode instantaneously increases to 30 kV, initiating discharge within the argon column inside the torch. Once initiated, the discharge continues even as the frequency sweep passes the resonant peak. The voltage required to sustain the discharge is significantly lower than the voltage required to initiate the discharge in argon gas.

[0069] The main instrument supplies a constant 24 Vdc to the ignition circuit, and its on / off operation is triggered by a signal from the plasma management system within the instrument.

[0070] exist Figure 9 In the specific embodiment shown, and as discussed above, all internal operations of the ignition module are fixed and require no external software control except for switching operations. However, in other applications, computer control of output voltage, modulation frequency, and range, etc., may be desired. A physical computer interface providing such control can be easily added.

[0071] Figure 9 Exemplary alternatives include one or more of the following: By using step-up transformers with different constructions, the intermediate oscillator frequency was set to different values.

[0072] There is no low-frequency modulation (in cases where the oscillator frequency can be precisely matched to the transformer's resonance, for example, by providing a fine-tuning potentiometer in the circuit board).

[0073] Single-ended output uses only one transformer and grounds the second electrode. For example, the second electrode can be completely absent, and the grounding terminal for discharge can be provided by some other grounded metal part of the torch.

[0074] The on / off control line can be omitted, and the switching operation can be controlled by switching the 24 Vdc as needed.

[0075] The above alternatives are not intended to be restrictive, but rather to illustrate some aspects that can be modified.

[0076] In some aspects, the external ignition device includes at least one electrode. For example, the external ignition device may include a single external electrode paired with an isolation element (e.g., a torch tube) in the discharge path, in which case the ignition mechanism can be described as dielectric barrier discharge (DBD). Similarly, as described herein, two electrodes located on opposite sides of a torch tube will provide ignition via dielectric barrier discharge (DBD). Dielectric barrier discharge (DBD) is a discharge between two electrodes separated by an insulating medium. In the above aspect where the two electrodes are located on opposite sides of an external torch tube, the torch tube is the insulating medium, and the discharge passes through the gas flowing through the torch. More generally, the mechanism can be described as an electrical breakdown discharge (or discharge), and examples of discharge to metallic components such as an ICP coil or torch tube base (e.g., a grounding component of an ICP torch) will also be described. In some cases, the ignition mechanism can be described as electrostatic discharge.

[0077] In some respects, the ignition mechanism via an external ignition electrode can be described as a glow discharge (e.g., in contrast to an arc discharge). However, as used herein, such a glow discharge will occur at or near atmospheric pressure, and if the plasma is ignited at low pressure, different external ignition equipment and operations are required. The plasma density produced by an external ignition electrode can be much lower than that of an arc discharge and can more closely resemble the density of a glow discharge.

[0078] The external ignition described herein may differ from one or more of the following ignition schemes: arc discharge, high voltage breakdown, DC current, Tesla coil, and / or direct contact between the ignition electrode and the gas to be ignited into plasma.

[0079] In some aspects, an external ignition device for igniting plasma in an ICP torch includes a circuit comprising: an oscillator, a first high-voltage transformer coupled to a first electrode, and optionally a second high-voltage transformer coupled to a second electrode, wherein the ignition device is configured to ignite the plasma by dielectric barrier discharge. The plasma can be ignited under atmospheric conditions (e.g., within 10% of 1 atm) or at least above 100 Torr. The external ignition device can be configured to provide an AC output voltage to at least one electrode (e.g., a first electrode and a second electrode), for example, wherein the first and second high-voltage transformers are connected to the circuit with opposite polarities. The device can provide a voltage difference of at least 1 kV between the first and second electrodes, for example, between 2 kV and 100 kV, between 5 kV and 50 kV, or between 20 kV and 40 kV. The maximum output voltage of the high-voltage transformers in the circuit is between 2 kV and 50 kV, for example, between 10 kV and 40 kV. In some aspects, the maximum voltage of the high-voltage transformers in the circuit is less than 1 MV, for example, less than 200 kV. In some respects, the AC voltage is at a frequency less than 1 MHz, for example, between 5 kHz and 100 kHz, or between 20 kHz and 40 kHz. The AC output voltage, and / or the frequency of the AC output voltage, is sufficient to ignite the plasma at atmospheric pressure (e.g., within 10% of 1 atm).

[0080] The external ignition device can be configured or operated to ignite the plasma via electrical breakdown discharge (e.g., via dielectric barrier breakdown). The plasma can be ignited by the capacitance between the portion of the outer torch body near the first electrode and the portion of the outer torch body near the second electrode.

[0081] In some respects, the external ignition device may not be configured or operated to ignite the plasma by a spark, or at least by an arcing action (e.g., an arc discharge). The external ignition device may not include a Tesla coil.

[0082] The device may include two electrodes. These electrodes may be located outside the outer torch, for example, within 5 mm or 3 mm of the outer torch wall of the ICP torch. Two high-voltage transformers are connected to the circuit with opposite polarities, such that their respective output voltages are out of phase. The two high-voltage transformers may have a maximum voltage output between 5 kV and 100 kV. The circuit also includes a voltage modulator configured such that an oscillator periodically satisfies the inherent resonant frequency of each of the first and second high-voltage transformers. The circuit operates at a fixed AC output voltage and frequency. Alternatively, at least one of the output voltage and its frequency can be controlled by a computer external to the external ignition device.

[0083] The device may be part of an ICP torch, wherein two electrodes are located outside the outer torch body of the ICP torch. The ICP torch may include an inner torch body, at least a portion of the outer torch body being coaxial with the inner torch body, and the first and second electrodes are positioned such that the axes passing through the first and second electrodes intersect with that portion of the outer torch body.

[0084] ICP Induction Coil Several aspects of this subject matter application include an ICP induction coil (ICP coil) used to sustain plasma (e.g., when operating at an RF frequency AC current). The ICP induction coil can be cylindrical in shape, meaning its shape is a helix defining the cylinder. Typically, for example, the coil has 3 turns. The ICP induction coil can be located within a torch box to surround an outer torch tube.

[0085] Standard cylindrical ICP induction coils are made of copper and are shaped as solid wire or hollow (tube). In contrast, various aspects of the ICP induction coils described in this subject matter application may include materials other than copper and shapes other than solid wire or hollow tube. The materials and / or shapes of the ICP induction coils discussed herein can reduce coil aging, for example, can reduce heat generation, oxidation, and / or deformation of the coil during operation to maintain plasma.

[0086] In some respects, ICP coils can be 3D printed. Alternatively, ICP coils can be machined or cast.

[0087] In some respects, an ICP coil may include annular fins. An annular fin is understood as a fin that widens as it extends from a central axis. Such fins may be difficult to form on machined metal because they may need to be deformed (stretched) in this manner to widen when the fin is bent to form the coil. Therefore, an ICP coil may include 3D-printed annular fins. Annular fins can accelerate the cooling of the ICP coil during operation (and thus also reduce oxidation). Annular fins may extend along at least one-eighth of a turn of the ICP coil and may extend along two or more turns. The inventors have found that continuous fins do not reduce the efficiency of the ICP coil. Metrics such as the operating frequency, inductance, and sustaining of the plasma remain unchanged compared to a design with gaps in the annular fins. The absence of gaps (or at least frequent gaps) in the annular fins also provides structural stability (e.g., to resist deformation during operation as described herein). Those skilled in the art may be concerned that current will travel partially along the outside of a coil with continuous annular fins, thereby reducing ICP efficiency or hindering coil operation.

[0088] The material and / or shape of the ICP coil can improve the structural stability of the coil, allowing for more flexible manufacturing processes and / or increased lifespan. For example, the operating life of the ICP coil of this subject application can be at least 5,000 hours, at least 10,000 hours, at least 20,000 hours, or at least 50,000 hours (e.g., without breakage, ICP efficiency reduction of no more than 10%, signal reduction detected by the quality analyzer of no more than 10%, or exceeding the frequency or induced tolerance).

[0089] In some respects, the ICP coil can be an alloy, such as an aluminum alloy. This alloy can be suitable for 3D printing. Alternatively or additionally, compared to copper and as discussed herein, this alloy can possess many additional properties.

[0090] In some respects, the ICP induction coil is a cylindrical coil comprising annular fins. The annular fins may be continuous within at least one-eighth of a turn of the cylindrical coil, for example, along at least two turns of the coil. The ICP induction coil may comprise primarily a metal or alloy that has a lower oxidation rate than copper during operation or throughout the instrument's life. The annular fins may be generally planar. The inner portion of the ICP induction coil is thicker than the outer portion. The inner portion may define a circular cross-section, and the outer portion is an annular fin. The inner portion of the ICP induction coil may have a smaller minimum diameter than the outer portion. The ICP induction coil may be solid. The ICP induction coil may not include multiple annular fins. One or more annular fins may be present along a large portion of three turns of the ICP induction coil. The distance from the innermost to the outermost portion of the annular fin may be at least twice the thickness of at least a portion of the annular fin.

[0091] In some respects, the length of the ICP coil (along its cylindrical axis) can be less than 10 cm, for example less than 5 cm.

[0092] The metal or alloy may be an aluminum alloy. The metal or alloy may have at least one of the following: lower conductivity than copper, lower melting temperature than copper, or lower ductility than copper. The ICP induction coil can be formed by 3D printing the metal or alloy, or alternatively by casting or mechanical manufacturing. The metal or alloy is one that reduces deformation during operation compared to copper, excluding the annular fins in the ICP induction coil. The metal or alloy is an alloy with reduced deformation compared to copper, for example, deformation perpendicular to the axis of the cylinder defined by the coil, and / or wherein the deformation is along the axis of the cylinder defined by the coil.

[0093] The ICP inductor coil may include a first portion closest to the longitudinal axis of the cylindrical coil, wherein the ICP inductor coil includes a second portion furthest from the longitudinal axis of the cylindrical coil, wherein the first portion is characterized by a first thickness, wherein the first thickness is measured perpendicular to the first axis, which is parallel to the longitudinal axis, wherein the second portion is characterized by a second thickness, wherein the second thickness is measured perpendicular to the second axis, which is parallel to the longitudinal axis, wherein the first thickness is greater than the second thickness.

[0094] Sample introduction Several aspects of this invention include sample introduction systems, such as particle (e.g., cell or magnetic bead) introduction systems or laser ablation systems. Particle introduction systems for mass spectrometry flow cytometry may include multiple components, such as a sample holder, a probe for accessing a sample in the sample holder, and / or a sample introduction jet for introducing a sample (e.g., a cell suspension) upstream of the spray chamber of an ICP torch. In some aspects, the sample holder may be configured to hold multiple samples, such as at least four, at least eight, or at least twelve samples. The sample holder may be movable to present the sample to the probe (e.g., it may be a carousel). Automated acquisition of multiple samples can take several hours. Therefore, several aspects of this subject application include sample introduction systems for maintaining cell suspensions. Such systems may include elements for hybrid applications beyond flow cytometry, such as those described by Al-Halhouli, Ala'Aldeen, et al. in "Passive micromixers with interlocking semi-circle and omega-shaped modules: Experiments and simulations" (…). Micromachines The elements described in 6.7 (2015): 953-968. In some respects, the radius of the turn and the flow velocity of the sample through the ring provide a lower Dean number (i.e., turbulence).

[0095] In some aspects, the sample introduction jet may include a sample ring in direct or indirect fluid communication with the probe and the spray chamber. The sample ring may include multiple turns (e.g., a helix defining a cylinder). The axis of the cylinder defined by the helix may be horizontally oriented (e.g., within 15 degrees perpendicular to the axis of gravity) to reduce the portion of the ring from which cells (or other particles) may precipitate. Optionally, the sample ring may also be positioned around a cylindrical stirrer in contact with the ring, wherein the stirrer maintains the particle suspension in the ring during delivery of the particle suspension to the spray chamber.

[0096] The sample introduction jet can be coupled to one or more reservoirs. These reservoirs may include waste reservoirs, cell acquisition solution reservoirs, wash solution reservoirs, and / or water reservoirs. The sample introduction jet may include a valve system (e.g., a rotary valve system) that directs the fluid flow from the reservoirs and the sample tube (sample loop). As described herein, the sample may be directed through a nebulizer, a spray chamber, a syringe, and then injected into ICP plasma, where particles in the solution (e.g., cells and / or magnetic beads) are nebulized and ionized before being analyzed by an analyzer (e.g., a simultaneous mass analyzer). In some aspects, the syringe is a heated syringe. U.S. Patent Publication No. US20190317082 provides a description of a heated syringe and cell acquisition scheme, which is incorporated herein by reference. In some aspects, the cell acquisition buffer may include a salt in solution that is free of carbon and heavy metals (e.g., any element having an atomic mass greater than 80).

[0097] The sample introduction system may include at least two syringes that alternate between a washing function and a sample introduction function. For example, a first pump may be used to draw sample, magnetic beads, washing solution, or cell acquisition solution into a sample loop. A second pump is a multi-port valve that connects the syringes to a waste bottle, a cell acquisition solution reservoir, and a switching valve. The primary function of the second pump is to push the sample, magnetic beads, solution, and / or cell acquisition solution from the sample loop into the nebulizer, and to push the cell acquisition solution directly from the reservoir into the nebulizer.

[0098] The sample introduction system may include at least two rotary valves, such as a directional valve and a switching valve. The directional valve may have multiple ports connected to a probe, a reservoir, and / or an empty port for extraction from a bubble. The position of the directional valve determines where the first pump draws from. The switching valve switches the sample ring between a loading position and an injection position. When the switching valve is in the loading position, the sample ring can be filled via a filling pump. In the injection position, the sample ring is aligned with the nebulizer, and the contents of the sample ring can be pushed into the nebulizer via a second pump. The first pump may be a filling pump. The second pump may be a push pump.

[0099] Figure 10 This is a schematic diagram of an exemplary sample ring of the sample introduction device of this subject application.

[0100] Figure 11 It is used for Figure 10 A schematic diagram of the stirrer for the sample ring. Figure 10 The spiral of the sample ring can wrap around Figure 11 The cylindrical body of the mixer is installed.

[0101] Figure 10 or Figure 11 The components can be in Figure 2 The sample shown is introduced into the jet.

[0102] Cell samples can be aspirated from the conveyor belt via a first pump. For example, such as... Figure 12 As shown, the sample can be drawn through a probe toward the reversing valve and then enters the sample loop through the switching valve at the loading position. Figure 13 Once the sample is loaded into the sample loop, the switching valve can be switched to the injection position and the sample is propelled into the nebulizer via the first pump. The cell acquisition solution can be used as a carrier to propel the sample into the syringe and into the system. Air bubbles can be introduced between the cell acquisition solution and the sample to prevent mixing at the interface between them.

[0103] In some respects, the sample ring is defined by a tight radius of curvature to define a tightly wound sample ring, achieving a lower Dean number, as described in the 2015 MicroMachines article. The sample ring can be horizontally aligned with the axis of rotation, so that the cell (or particle) flow (at the lower end of the ring) experiences minimal sedimentation time due to gravity. To further prevent cell sedimentation within the sample ring, a stirrer (vibrating rod) can be used. However, contrary to its use in other applications, vibration does not precipitate or trap material during its transport; instead, it simply adds agitation to the flow to keep the cell suspension within the carrier fluid. This is similar to having summer students periodically tap the sample ring—it works just as well and is less expensive.

[0104] Although the sample introduction device can be used in combination with an ICP analyzer, it can also be used alternatively or in combination with any particle-based analytical system (e.g., flow cytometry).

[0105] The sample introduction device of this application may include a sample ring, wherein the sample ring rotates at least 3 turns. These turns may surround a cylindrical stirrer. The sample ring may form a helix comprising at least 5 turns. The helix may define a cylinder having an axis within 15 degrees perpendicular to the axis of gravity.

[0106] Sampling systems and their usage methods (e.g., performed by a computer-readable medium) can improve productivity by utilizing built-in blockage detection, automatic blockage clearing (i.e., unblocking blockages), and / or shutdown.

[0107] In some respects, the sample system is part of the precipitate resuspension workflow and is performed prior to sample loading. During mixing, the probe line and filling pump can work together to act like a pipette, drawing and dispensing volumes (e.g., between 25 μL and 250 μL) multiple times within the tube. The user can select a mixing force value (e.g., between 1 and 10) to define the rate at which that volume is ejected into the sample tube (e.g., where 1 represents the lowest mixing force and 10 represents the strongest mixing force). This parameter can be set to a default value (e.g., 5).

[0108] During sample acquisition, the probe line can agitate the sample to prevent cell precipitation. The user can select an agitation speed value (e.g., between 0 and 9) to define the speed at which the probe line rotates (e.g., where 0 disables agitation and 9 is the fastest speed). This parameter can be set to a default value (e.g., 5). During acquisition, the inside and / or outside of the probe line can be cleaned when the user selects a pre-cleaning cycle, or when that pre-cleaning cycle is otherwise performed by a computer-readable medium.

[0109] The default sample loop vibration setting can help reduce cell deposition within the sample loop.

[0110] The device may also include a nebulizer in fluid communication with a sample loop. The nebulizer may be in fluid communication with a spray chamber. The spray chamber may be configured to deliver particles to a syringe. The device may include a sample holder configured to hold one or more samples. The sample holder may be configured to hold multiple tubes, for example, wherein the sample holder is configured to cool multiple tubes. The device may include multiple pumps, multiple valves, multiple reservoirs, and / or multiple tubes configured to transfer a suspension of cells from the tubes provided by the sample holder to a probe, through the sample loop, and out of the nebulizer. The device may include a pressure sensor configured to detect a pressure drop when the probe is clogged by one or more particles, and optionally include a computer-readable medium storing multiple instructions that, when executed, control a processor to operate the sample introduction system, for example, wherein the multiple instructions include automatically reversing flow (or regulating pressure, e.g., increasing pressure) when clog is detected in the probe, thereby clearing the clog. The processor may operate the sample introduction system to resuspend cells in the tubes before transferring the cells.

[0111] The computer-readable medium of this subject application may include an automated sampler module that can operate the system described herein to automate a blockage detection and removal workflow. Various aspects of this subject application include one or more steps of the following automated method steps, and a computer-readable medium configured to perform these steps (e.g., a computer-readable medium of a sample introduction system as described herein, or a computer-readable medium of a mass spectrometry flow cytometry system including such a sample introduction system). At least two pressure sensors may be present in the sample introduction jet, for example, in a pump (e.g., Figure 12 and Figure 13 The first sensor on the push pump shown and the filling pump (e.g., Figure 12 and Figure 13 A second sensor is located on the filling pump shown in the diagram. During sample injection, readings can be generated from pushing the pump (e.g., at least once per minute, such as once every 5 to 6 seconds). If the average pressure in the readings, or the average pressure over a predetermined number of consecutive readings (e.g., two or more readings, three or more readings, five or more readings, such as five readings), reaches a set threshold, a blockage may be detected (e.g., and reported to the user). Sample collection (e.g., including sample injection) can then be paused and an automatic unblocking routine initiated.

[0112] A clogging removal routine may include switching from injection mode to loading mode, which allows the use of a push pump to flush the nebulizer while the sample in the sample loop remains undisturbed. Initial attempts to remove the clogging can be accomplished through pulsed high-flow-rate aspiration and flushing (e.g., for approximately 1 to 2 minutes). If the clogging is not cleared, a clogging identification workflow can be run (e.g., in which two pressure sensors are used to determine whether the clogging is in the sampling loop or downstream of the sampling loop, such as in the nebulizer line or nebulizer). The clogging removal process can then focus on the location of the clogging. During the clogging removal process, the flow rate level and / or pulse rate can be increased (e.g., in the sample introduction jet, such as at a probe as described herein). In some respects, a clogging removal pressure can be applied (e.g., user-inputted) in any of the above steps of increasing pressure, flow rate, or pulse rate. For example, the clogging removal pressure can be greater than 5 psi (pounds per square inch), greater than 10 psi, greater than 15 psi, for example between 5 and 40 psi, or between 10 and 20 psi. In some respects, a predetermined maximum number of blocking events (e.g., user input) can trigger the end of sample collection.

[0113] If the blockage is successfully cleared using the automated workflow, acquisition can be resumed. If the blockage cannot be cleared using the automated workflow, acquisition can be stopped and the sample returned to the sample tube (if a recover sample was specified in the acquisition template). The blockage can then be cleared manually (e.g., the software can instruct the user to perform manual blockage clearing).

[0114] ICP Analyzer The ICP analyzer of this subject application may include any ICP torch chamber described herein, coupled to an atomic analyzer such as MS or AES. The analyzer may be a simultaneous mass analyzer, such as TOF-MS or sector magnetic field MS. The ICP analyzer may be a mass spectrometer or imaging mass spectrometer. The ICP analyzer can be operated to provide an external gas flow rate of less than 20 L / min. The ICP analyzer can ignite the plasma through a dielectric barrier discharge under atmospheric conditions. The ICP analyzer can be used to analyze biological samples, such as mass-labeled cells or tissue sections. In some respects, the ICP analyzer can be used to analyze non-biological samples.

[0115] System monitoring equipment In some respects, mass spectrometry flow cytometry systems or sample introduction systems, as described herein, also include system monitoring devices configured to transmit system operating data (such as one or more settings and / or real-time measurements described herein) to a database. This device may operate independently of the computer used to operate the system, or it may communicate with such a computer. Alternatively or additionally, the computer may perform the functions described herein for the device. The device may be a wireless device. The database may include system operating data from different systems located in geographically different locations. The device may communicate with the database via a wireless router.

[0116] In some respects, settings can be selected from any parameter or value input by the user. In some respects, real-time measurements can include measurements within the system or measurements performed by environmental sensors (e.g., measurements of humidity, pressure, and / or temperature outside the system). Real-time internal measurements can include one or more of the following: clogging events (e.g., data directly from pressure sensors or the frequency of clogging), flow rates (e.g., the flow rate of sample fluid or one or more gases described herein (e.g., atomizing gas, carrier gas, internal gas, and / or external gas), one or more components (e.g., temperature within the torch assembly or the temperature of the ICP sensing coil), the voltage of the system's mass detector, the current of one or more cones (e.g., sampling cones and / or snipping cones downstream of the ICP torch), the frequency or power at which the ICP sensing coil operates, the mass signal from elemental standard beads, mass detector signals (e.g., detector signals above a predetermined threshold that could indicate detector damage or wear, cellular events), the amount or pressure of gas in a storage container (e.g., a gas canister or dehumidifier supplying gas to the system), system uptime, etc.

[0117] When a laser ablation system (e.g., for tissue imaging) is configured to deliver a laser ablation plume to the mass cytometer of this subject matter application (e.g., instead of suspended cells or magnetic beads), it may provide one or more additional settings and / or real-time measurements associated with the laser ablation system. These may include, for example, laser ablation settings (e.g., power, operating voltage, operating frequency, operating mode, and / or power dissipation), ablation chamber fluid parameters (e.g., the carrier gas flow rate and / or sheath flow rate for delivering the ablation plume to the mass cytometer described herein), humidity within the laser ablation plume, and the width of the laser ablation plume as measured by a mass detector.

[0118] In some respects, system operation data from one or more systems operating on the same system can be used to identify preventative maintenance required on that system. At this point, the user can be notified of the need for such maintenance (e.g., prompted to schedule it). Maintenance can be instrument adjustment, instrument cleaning (e.g., cleaning of the sample introduction jet, the torch body or its tubing, or the sampling cone downstream of the ICP torch), or replacement of certain components (e.g., replacement of the laser, mass detector, gas reservoir, torch body or its tubing, nebulizer, or another element of the sample introduction jet as described herein).

[0119] practicality Several aspects of the systems and methods described herein can provide longer-life ICP components, easier user operation, and / or reduced maintenance or operating costs. For example, the ICP induction coil aspect described herein can improve lifespan compared to conventional coils. The removable torch described herein allows for easy maintenance and low-cost replacement (e.g., easy access to the torch tube, which can be detached from the larger component to be replaced). Eddy currents in the torch assembly can reduce the external gas flow required to sustain the plasma. External ignition electrodes enable removable torches and / or can have a longer lifespan than electrodes inserted into the torch body. Generally, the longer lifespan can be at least twice as long or at least five times the lifespan before components break or become significantly damaged (e.g., if operating at less than 90% or 80% of the efficiency after replacement, where efficiency is the energy required to operate the equipment or the signal strength detected by the analyzer downstream of the ICP). The sample introduction system described herein can increase user-off-time and enable automated sample introduction of multiple samples.

Claims

1. A sample introduction device, comprising: Sample ring; Cylindrical mixer; The sample ring surrounds the cylindrical stirrer at least three times.

2. The sample introduction device according to claim 1, wherein, The sample ring forms a spiral, and the spiral includes at least 5 turns.

3. The sample introduction device according to claim 2, wherein, The spiral defines a cylinder with an axis that is within 15 degrees of the axis of gravity.

4. The sample introduction device according to any one of claims 1 to 3, further comprising a sprayer, the sprayer being in fluid communication with the sample annulus, wherein, The sprayer is in fluid communication with a spray chamber, wherein the spray chamber is configured to deliver particles to the syringe.

5. The sample introduction device according to any one of claims 1 to 4, further comprising a sample holder configured to hold a plurality of tubes.

6. The sample introduction device according to claim 5, wherein, The sample holder is configured to cool the plurality of tubes.

7. The sample introduction device according to any one of claims 1 to 6, further comprising a plurality of pumps, a plurality of valves, a plurality of reservoirs, and a plurality of tubes, said plurality of pumps, said plurality of valves, said plurality of reservoirs, and said plurality of tubes being configured to transfer a suspension of cells from a tube provided by the sample holder to a probe, through the sample loop, and out of the nebulizer.

8. The sample introduction device of claim 7 further includes a pressure sensor configured to detect a pressure drop when the probe is blocked by one or more particles.

9. The sample introduction device of claim 8, further comprising a computer-readable medium storing a plurality of instructions, which, when executed, control a processor to operate the sample introduction system.

10. The sample introduction device according to claim 9, wherein, The multiple instructions include automatically reversing the flow when a blockage is detected in the probe, thereby clearing the blockage in the probe.

11. The sample introduction device according to claim 10, wherein, The processor operates the sample introduction system to resuspend the cells in the tube before transferring them.

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