Inductively coupled plasma torch structure with protected injector

Abstract

An inductively coupled plasma (ICP) torch is described that includes an injector protector that protects an end of the injector. System embodiments include, but are not limited to, a tubular sample injector configured to receive an aerosolized sample in an interior defined by a wall of the tubular sample injector, an injector protector that surrounds at least a portion of the tubular sample injector, an inner tube that surrounds at least a portion of the injector protector to form a first annular space between the inner tube and the injector protector, the inner tube defining at least one inlet port for introducing an auxiliary gas into the first annular space, and an outer tube that surrounds at least a portion of the inner tube to form a second annular space, the outer tube defining at least one inlet port for introducing a cooling gas into the second annular space.

Description

Technical Field

[0001] (Related Application) This application claims the benefit of 35 USC §119(e) of U.S. Provisional Application No. 63 / 179,715 entitled "INDUCTIVELY COUPLED PLASMA TORCH STRUCTURE FOR LOW COOLING GAS FLOWS" filed on April 26, 2021, U.S. Provisional Application No. 63 / 179,759 entitled "ICP TORCH ASSEMBLY WITH PROTECTED INJECTOR" filed on April 26, 2021, and U.S. Provisional Application No. 63 / 179,827 entitled "FLARED LOW-FLOW TORCH FOR ICP AND ICPMS" filed on April 26, 2021. U.S. Provisional Application Nos. 63 / 179,715, 63 / 179,759, and 63 / 179,827 are incorporated herein by reference in their entireties. Background Art

[0002] Inductively coupled plasma (ICP) mass spectrometry is an analytical technique commonly used for measuring trace element concentrations and isotope ratios in liquid samples. ICP mass spectrometry uses an electromagnetically generated, partially ionized argon plasma that reaches a temperature of approximately 7000K. When a sample is introduced into the plasma, the high temperature causes sample atoms to ionize or emit light. Since each chemical element produces a characteristic mass or emission spectrum, measuring the spectrum allows determination of the elemental composition of the original sample.

[0003] A sample introduction system may be used to introduce a liquid sample into an ICP mass spectrometer (e.g., an inductively coupled plasma mass spectrometer (ICP / ICPMS), an inductively coupled plasma atomic emission spectrometer (ICP-AES), etc.). For example, the sample introduction system may take aliquots of the liquid sample from a container and then transport the aliquots to a nebulizer, which converts the aliquots into a polydisperse aerosol suitable for ionization in the plasma by the ICP mass spectrometer. The aerosol is then sorted in a spray chamber to remove larger aerosol particles. Once out of the spray chamber, the aerosol is introduced into the ICPMS or ICPAES instrument for analysis. Often, sample introduction is automated, allowing for the efficient introduction of a large number of samples into the ICP mass spectrometer. [Overview of the initiative]

[0004] An inductively coupled plasma (ICP) torch is described that facilitates a laminar flow of cooling gas introduced through multiple input ports between an outer tube and an inner tube, which are configured to surround an injector for introducing an aerosolized sample into the plasma. Embodiments of the system include, but are not limited to, an inner tube and an outer tube that surrounds at least a portion of the inner tube to form an annular space, the outer tube defining multiple inlet ports for introducing the cooling gas into the annular space as a laminar flow through each of the multiple inlet ports.

[0005] Embodiments of the system include, but are not limited to, a tubular sample injector configured to receive a sample aerosolized inside a wall defined by the wall of the tubular sample injector; an inner tube surrounding at least a portion of the tubular sample injector and forming a first annular space between the inner tube and the wall of the tubular sample injector, the inner tube defining a first plurality of inlet ports for introducing an auxiliary gas into the first annular space; and an outer tube surrounding at least a portion of the inner tube and forming a second annular space, the outer tube defining a second plurality of inlet ports for introducing a cooling gas as a laminar flow into the second annular space.

[0006] Embodiments of the method include introducing an aerosolized sample into the interior of a tubular sample injector of an inductively coupled plasma torch, the inductively coupled plasma torch including an inner tube surrounding at least a portion of the tubular sample injector and forming a first annular space between the inner tube and the wall of the tubular sample injector, the inner tube defining a first plurality of inlet ports for introducing an auxiliary gas into the first annular space, and an outer tube surrounding at least a portion of the inner tube and forming a second annular space, the outer tube defining a second plurality of inlet ports for introducing a cooling gas into the second annular space. Embodiments of the method include, but are not limited to, introducing an auxiliary gas into the first annular space of the inductively coupled plasma torch via the first plurality of inlet ports, and introducing a cooling gas into the second annular space of the inductively coupled plasma torch at a flow rate of less than 12 L / min via the second plurality of inlet ports.

[0007] An inductively coupled plasma (ICP) torch includes an injector protector that shields the injector end during low-cooling gas operation of the torch. Embodiments of the system include, but are not limited to, a tubular sample injector configured to receive a sample aerosolized inside defined by the walls of the tubular sample injector; an injector protector surrounding at least a portion of the tubular sample injector; an inner tube surrounding at least a portion of the injector protector and forming a first annular space between the inner tube and the injector protector, the inner tube defining at least one inlet port for introducing an auxiliary gas into the first annular space; and an outer tube surrounding at least a portion of the inner tube and forming a second annular space, the outer tube defining at least one inlet port for introducing a cooling gas into the second annular space.

[0008] Embodiments of the system include, but are not limited to, a tubular sample injector configured to receive an aerosolized sample inside defined by the walls of the tubular sample injector; an injector protector surrounding at least a portion of the tubular sample injector; an inner tube surrounding at least a portion of the injector protector and forming a first annular space between the inner tube and the injector protector, the inner tube defining at least one inlet port for introducing an auxiliary gas into the first annular space; an outer tube surrounding at least a portion of the inner tube and forming a second annular space, the outer tube defining at least one inlet port for introducing a cooling gas into the second annular space; and a gas introduction sheath coupled to the respective input ends of the tubular sample injector and the injector protector for introducing gas between the tubular sample injector and the injector protector, the gas introduction sheath defining a gas inlet port configured to receive gas for introduction into a third annular space defined between the injector protector and the tubular sample injector.

[0009] Embodiments of the method include introducing an aerosolized sample into the interior of a tubular sample injector of an inductively coupled plasma torch, the inductively coupled plasma torch including an injector protector surrounding at least a portion of the tubular sample injector, an inner tube surrounding at least a portion of the injector protector and forming a first annular space between the inner tube and the injector protector, the inner tube defining at least one inlet port for introducing an auxiliary gas into the first annular space, and an outer tube surrounding at least a portion of the inner tube and forming a second annular space, the outer tube defining at least one inlet port for introducing a cooling gas into the second annular space. Embodiments of the method include, but are not limited to, introducing an auxiliary gas into the first annular space of the inductively coupled plasma torch via at least one inlet port of the inner tube, and introducing a cooling gas into the second annular space of the inductively coupled plasma torch at a flow rate of less than 12 L / min via at least one inlet port of the outer tube.

[0010] An inductively coupled plasma (ICP) torch includes a tapered outer end of an outer tube, which separates the outer end from the plasma during low-cooling gas operation of the torch. Embodiments of the system include, but are not limited to, a tubular sample injector configured to receive an aerosolized sample inside defined by the wall of the tubular sample injector; an inner tube surrounding at least a portion of the tubular sample injector and forming a first annular space between the inner tube and the wall of the tubular sample injector, the inner tube defining at least one inlet port for introducing an auxiliary gas into the first annular space; and an outer tube surrounding at least a portion of the inner tube and forming a second annular space, the outer tube defining at least one inlet port for introducing a cooling gas into the second annular space and having a flared region at the outlet of the outer tube.

[0011] Embodiments of the system include, but are not limited to, an inner tube configured to receive at least a portion of a tubular sample injector, and an outer tube surrounding at least a portion of the inner tube to form an annular space, wherein the outer tube defines at least one inlet port for introducing a cooling gas into the annular space, and has a flared region at the outlet of the outer tube, the flared region being located downstream of the outlet end of the inner tube, and the outlet end of the inner tube being located inside the outer tube.

[0012] Embodiments of the method include introducing an aerosolized sample into the interior of a tubular sample injector of an inductively coupled plasma torch, the inductively coupled plasma torch including an inner tube surrounding at least a portion of the tubular sample injector and forming a first annular space between the inner tube and the wall of the tubular sample injector, the inner tube defining at least one inlet port for introducing an auxiliary gas into the first annular space, and an outer tube surrounding at least a portion of the inner tube and forming a second annular space, the outer tube defining at least one inlet port for introducing a cooling gas into the second annular space and having a flared region at the outlet of the outer tube. Embodiments of the method include, but are not limited to, introducing an auxiliary gas into the first annular space of the inductively coupled plasma torch via at least one inlet port of the inner tube, and introducing a cooling gas into the second annular space of the inductively coupled plasma torch at a flow rate of less than 12 L / min via at least one inlet port of the outer tube.

[0013] This summary provides a simplified introduction to some of the concepts described later in the "Detailed Description." This summary is not intended to identify the main or essential features of the claims, nor is it intended to be used as an aid in determining the scope of the claims.

[0014] Detailed explanations will be provided with reference to the attached diagrams. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic diagram of a sample analysis system using an ICP torch, similar to the embodiments described herein. [Figure 2] This is a side view of an ICP torch according to an embodiment of the present disclosure. [Figure 3] Figure 2 is a cross-sectional side view of a portion of the ICP torch. [Figure 4] This is a cross-sectional end view of the ICP torch shown in Figure 2, taken along line 4-4 shown in Figure 3. [Figure 5]This is a partial isometric view of an ICP torch according to an embodiment of the present disclosure. [Figure 6A] This is a cross-sectional side view of an ICP torch having an injector protector tube, according to an embodiment of the present disclosure. [Figure 6B] Figure 6A is a cross-sectional side view of an ICP torch, in which, in accordance with the embodiments of this disclosure, the end of the injector protector tube is substantially flush with the end of the injector. [Figure 6C] Figure 6A is a cross-sectional side view of an ICP torch, in which, in accordance with the embodiments of this disclosure, the end of the injector protector tube extends beyond the end of the injector. [Figure 6D] Figure 6A is a cross-sectional side view of an ICP torch, wherein, in accordance with an embodiment of the present disclosure, the ICP torch has an end of a tapered injector protector tube that extends beyond the end of a tapered injector. [Figure 7A] Figure 6C is an isometric view of an ICP torch having a gas introduction sheath coupled to the sample introduction end of the ICP torch, in accordance with the embodiments of this disclosure. [Figure 7B] Figure 7A is a cross-sectional side view of the ICP torch. [Figure 8A] This is an isometric view of an ICP torch having a flare outlet, in accordance with the embodiments of this disclosure. [Figure 8B] Figure 8A is a cross-sectional side view of the ICP torch. [Figure 9A] This photograph shows experimental results of the outlet of an ICP torch with a cylindrical, non-flared outlet, illustrating devitrification and precipitation after a period of operation. [Figure 9B] This photograph shows experimental results of an ICP torch with a flare outlet, demonstrating that damage was minimized after being used for the same period as the torch in Figure 9A. [Modes for carrying out the invention]

[0016] (overview) Inductively coupled plasma mass spectrometers (ICP / ICPMS), inductively coupled plasma atomic emission spectrometers (ICP-AES), inductively coupled plasma optical emission spectrometers (ICP-OES) and other ICP spectroscopic analyzers maintain the plasma generated to ionize aerosolized samples, and utilize argon gas (Ar) to cool the torch from the high temperature generated by the torch for sample analysis. For example, the temperature of ICP may exceed 8000K, which is higher than the melting point of torch materials composed of quartz, alumina, silicon nitride, and other ceramic or glassy materials. The main flow of argon gas, sometimes referred to as plasma gas or cool gas, enters the annular gap between the two torch tubes, helps to thermally insulate the torch material from the plasma, and suppresses initial degradation (sometimes referred to as devitrification), melting, or other damage that may require replacement or may contaminate the sample during analysis. However, if the gas flow rate is too low, the plasma formed by the torch will intrude into the end of the torch tube and / or the end of the sample injector concentrically arranged inside the torch tube, which may cause devitrification or other damage to the torch tube and / or the sample injector.

[0017] Furthermore, the ICP apparatus can be used to process large volumes of samples during bulk sample analysis periods in which the ICP torch is operated continuously or substantially continuously. These operating periods involve a constant or substantially constant flow of gas, such as argon gas, and electricity to maintain the plasma within the ICP torch, resulting in operating costs for the ICP apparatus. Furthermore, generally, as the ionization power of the ICP torch increases, more power is required to maintain the plasma, which increases the operating cost of the ICP torch compared to operating the ICP torch at a lower ionization power for the same amount of time. The cost of operating an ICP torch often increases exponentially (compounded) when the torch is operated over continuous or substantially continuous operating periods at a sufficiently high gas flow rate to position the plasma sufficiently far from the output end of the torch to prevent damage to the torch. For this reason, prolonged use of conventional ICP torches can result in high argon consumption required to prevent torch damage due to plasma positioning, increasing overall operating costs.

[0018] Accordingly, in one aspect, the present disclosure applies to systems and methods for controlling the flow of ICP torch gas during introduction of gas into an ICP torch and into the torch body. For example, the present disclosure can be applied to operation of an ICP torch that utilizes a lower argon cooling gas flow rate to enable operation of the ICP at a lower ionization power compared to ICP torches that introduce cooling gas substantially as turbulent flow. In embodiments, the torch includes a plurality of inlet ports oriented substantially tangentially to the annular space between the outer tube and the inner tube of the torch, to supply cooling gas as a substantially laminar flow within the annular space as the cooling gas travels from the first end to the second end of the torch. The inlet ports may be arranged longitudinally along the outer tube of the torch. In embodiments, the torch includes a second plurality of inlet ports oriented substantially tangentially to the annular space between the inner tube and the injector of the torch, for supplying plasma gas to the torch.

[0019] (Examples) Referring to Figures 1 through 5 in general terms, a system 100 for sample analysis utilizing an ICP torch to prepare a sample for analytical measurement is shown. Referring to Figure 1, for example, the system 100 is shown to include an ICP torch (referred to herein as “torch 102”) that accepts a sample 104 and one or more gases 106 for preparing the sample to be analyzed by an ICP analyzer 108. The sample 104 may include an aerosolized sample for introduction into the injector of the torch 102. For example, the sample 104 may be transported from a spray chamber used to remove large aerosol particles that may adversely affect the plasma flame, while allowing a portion of the aerosolized sample to pass through the torch 102. The gases 106 may include a plasma gas (e.g., Ar), a cooling or auxiliary gas (e.g., Ar, nitrogen (N2), etc.), a transport gas, etc. The gases 106 may include Ar for use as one or more of the plasma gas, cooling gas, and transport gas, but in certain embodiments, other gases may be used instead of or in addition to Ar. An example of introducing gas 106 into the torch 102 will be described with reference to Figures 2 to 4.

[0020] Referring to Figures 2 to 5, the torch 102 is shown in accordance with the embodiments of this disclosure. The torch 102 generally includes an inner tube 110 and an outer tube 112 having a structure that controls the flow of gas introduced into the torch 102. The inner tube 110 defines an interior 114 configured to receive an injector 116 used to introduce an aerosolized sample into the torch 102. The outer tube 112 surrounds at least a portion of the inner tube 110, and an annular region 118 is formed between the outer surface 120 of the inner tube 110 and the inner surface 122 of the outer tube 112. The annular region 118 is configured to receive a flow of gas (e.g., cooling gas, plasma gas, etc.) into the torch 102 to facilitate plasma generation and protect the material of the outer tube 112 from the heat of the plasma generated by the torch 102. The outer tube 112 includes a plurality of inlet ports 124 formed in the wall of the outer tube 112 between the inner surface 122 and the outer surface 126 of the outer tube 112. Figures 2 to 5 show four inlet ports 124 formed in the outer tube 112, but the disclosure is not limited to four inlet ports 124 and may include fewer than four inlet ports 124 (e.g., two inlet ports, three inlet ports) or more than four inlet ports 124 (e.g., five inlet ports, six inlet ports, seven inlet ports, etc.). Multiple inlet ports 124 can provide multiple inlets for such introduction under laminar flow conditions while facilitating an increase in the intensity of the gas introduced into the torch 102 to provide tangential flow.

[0021] The inlet port 124 has a structure that directs the cooling gas into an annular region 118 between the inner tube 110 and the outer tube 112 in a direction that allows for laminar flow of the cooling gas within the torch 102. In the embodiment, one or more inlet ports 124 are positioned substantially in contact with the annular region 118 (for example, the ends of the inlet ports 124 are substantially in contact with the inner surface 122 of the outer tube 112). In the embodiment, each of the inlet ports 124 is positioned substantially in contact with the annular region 118. The torch 102 may include inlet ports 124 oriented through the outer tube 112 such that the outlets in the annular region 118 face various angles (for example, shown as α in Figure 4) to supply cooling gas into the annular region 118. In the embodiment, the value of α may range from about 10 degrees to about 20 degrees.

[0022] In the embodiment, the torch 102 includes an inlet port 124 substantially longitudinally arranged along the torch 102 between the inlet end 128 and the outlet end 130 of the torch 102. For example, Figures 2 to 5 show the inlet port 124 arranged in a substantially linear pattern longitudinally along the outer tube 112. Although the inlet port is shown as a substantially circular cross-section arranged substantially linearly, the torch 102 is not limited to such a configuration and may include other shapes and patterned arrangements (e.g., non-linear arrangements) for delivering the cooling gas to the annular region 118 without departing from the scope of the present disclosure.

[0023] The inner tube 110 and the injector 116 define an annular region 132 within the interior 114 when the injector 116 is positioned within the interior 114. In some embodiments, the injector 116 and the inner tube 110 are fixedly coupled, such as by fusing them as a single unit. In some embodiments, the injector 116 and the inner tube 110 are detachably coupled, such as by providing a detachable injector (e.g., a threaded detachable injector) that includes one or more mating features for screwing into or otherwise detachably coupling with the inner tube 110. The injector 116 can be protected within the inner tube 110, and optimization of the central channel gas flow independent of the aerosol flow of the sample is possible.

[0024] The inner tube 110 includes one or more features for receiving auxiliary gas into an annular region 132 to assist in the formation of plasma by the torch 102. For example, the inner tube 110 is shown to include a plurality of inlet ports 134 formed in the wall of the inner tube 110 between the outer surface 120 of the inner tube 110 and the inner surface 136 of the inner tube 112 configured to receive the flow of auxiliary gas to the torch 102, in order to assist in the formation of plasma by the torch 102 by adjusting the position of the plasma. Figures 2 to 5 show four inlet ports 134 formed in the inner tube 110, but the disclosure is not limited to four inlet ports 134 and may include fewer than four inlet ports 134 (e.g., two inlet ports, three inlet ports) or more than four inlet ports 124 (e.g., five inlet ports, six inlet ports, seven inlet ports, etc.). Alternatively, the inner tube 110 may include a single inlet port 134. In the embodiment, one or more inlet ports 134 are positioned substantially in contact with the annular region 132 (for example, the ends of the inlet ports 134 are substantially in contact with the inner surface 136 of the inner tube 110) to provide auxiliary gas in the annular region 132 as substantially laminar flow. In the embodiment, each of the inlet ports 134 is positioned substantially in contact with the annular region 132. Similar to the orientation of the inlet ports 124, the torch 102 may include inlet ports 134 oriented through the inner tube 110 such that the outlets in the annular region 132 face various angles to supply auxiliary gas in the annular region 132. In the embodiment, the inner tube 110 expands outward toward the inner surface 122 of the outer tube 112 such that the area of ​​the annular region 118 decreases as the torch 102 moves from the inlet end 128 to the outlet end 130. For example, Figure 3 shows an embodiment of an inner tube 110 that includes a tulip portion 138 that expands toward the outer tube 112, providing a smaller annular region 118 that follows the tulip portion 138 toward the outlet end 130.In this embodiment, the inner tube 110 defines a gap between the outer surface 120 of the inner tube 110 and the inner surface 122 of the outer tube 112, having a dimension of approximately 0.5 mm toward the outlet end 130 following the tulip portion 138. To facilitate operation of the torch 102 at low cooling gas flow rates to the inlet port 124 (e.g., less than 12 L / min), the relatively narrow gap between the outer surface 120 of the inner tube 110 and the inner surface 122 of the outer tube 112 increases the gas velocity downstream of the tulip portion 138, allowing plasma formation to be maintained at low cooling gas flow rates, thereby reducing the amount of cooling gas used for operating the torch 102 compared to a torch that requires a cooling gas flow rate of 12 L / min or more for operation.

[0025] In this embodiment, a portion of the torch 102 can be integrally formed. For example, the outer tube 112 may be fused to a portion of the inner tube 110, allowing the outer tube 112 to be held fixed relative to the inner tube 110. Alternatively or additionally, the inner tube 110 may be fused to a portion of the injector 116.

[0026] In the embodiment shown in Figure 5, the torch 102 may include an ignition hole 140 formed in the outer tube 112 to provide access to the inside of the torch 102 for a spark or other ignition source to ignite the plasma for the operation of the system 100. In the embodiment, all or part of the torch 102 may be formed from a doped quartz glass material, including but not limited to cerium-doped quartz. Alternatively or additionally, all or part of the torch 102 may be formed from other materials, including but not limited to alumina, platinum, and sapphire.

[0027] Torch 102 demonstrates high plasma robustness even during low flow rate gas flows, such as when the flow rate from the cooling gas to the inlet port 124 is low. For example, Torch 102 can be used with cooling gas flow rates of less than 12 L / min to the inlet port 124. In the embodiment, the cooling gas flow rate to the inlet port 124 is approximately 5 L / min to approximately 12 L / min. Torch 102 showed high plasma robustness while the RF power supplied to the coil surrounding Torch 102 was low. For example, the torch provided approximately 1000 W of ion power. Torch 102 showed high plasma robustness during low RF power supplied to the coil surrounding Torch 102, in combination with the introduction of a low flow rate gas flow to Torch 102. In the embodiment, plasma robustness allows Torch 102 to be without a viewing slot, which can provide a shorter Torch 102 (e.g., torch length) compared to a torch that includes a viewing slot. In the embodiment, due to its plasma robustness, the torch 102 can utilize a single injector for both organic and inorganic applications, which provides increased residence time for organic applications that typically use narrower injectors. For example, an injector configured for use with the torch 102 can reduce the injection rate of the organic sample, which increases the residence time in the ICP to improve matrix tolerance.

[0028] In the embodiment, the torch 102 may include an injector protector tube within the inner tube 110 that surrounds at least a portion of the injector 116 to insulate and shield the injector 116 from the plasma, thereby reducing the opportunity for the injector 116 to overheat and / or for contaminants measurable in the ICPMS mass spectrum to be introduced in other ways. For example, the torch 102 has an injector protector 600 within the inner tube 110, as shown in Figures 6A to 6D, the injector protector 600 surrounds at least a portion of the injector 116, the injector protector 600 is positioned between the injector 116 and the inner tube 110, and the inner tube 110 is positioned between the injector protector 600 and the outer tube 112. In the embodiment, the outer tube 112, inner tube 110, injector protector 600, and injector 116 are arranged concentrically and in order from the outside.

[0029] The injector protector 600 can protect the injector 116 from the energy associated with the plasma formed by the torch, assist in the relative positioning of the plasma, and push the plasma away from the outlet tip of the injector 116. Generally, the injector protector 600 is formed from a chemically resistant material that can withstand prolonged exposure to high temperatures (e.g., without fusing or decomposing), including but not limited to silica (SiO2), alumina (Al2O3), or zirconia (ZrO2). By shielding the injector 116 from the plasma, the injector protector 600 can prevent false background of material flowing out of the injector 600 during the operation of the torch 102. In some embodiments, the injector protector 600 is formed from the same material as the inner tube 110 and / or the outer tube 112. In some embodiments, the injector protector 600 is formed from a different material than the inner tube 110 and / or the outer tube 112. In the embodiment, the injector 116 and the injector protector 600 are fixedly joined, for example, by fusing them as a single integrated structure. In the embodiment, the injector 116 and the injector protector 600 are detachably joined, for example, by providing a detachable injector (e.g., a threaded detachable injector) that includes one or more mating features for screwing into the injector protector 600 or for detachably joining to the injector protector 600 by other means.

[0030] The injector protector 600 may be positioned with the inner tube 110 such that an annular region 132 is formed between the inner tube 110 and the injector protector 600. The injector protector 600 includes an output end 604 of the inner tube 110 and an output end 602 positioned in the outer tube 112 adjacent to the output end 606 of the injector 116. For example, the torch 102 is shown in Figures 6A to 6D such that the output end 602 of the injector protector 600 is substantially flush with the output end 604 of the inner tube 110, but the disclosure is not limited to such relative positional relationships. The position of the output end 602 of the injector protector 600 relative to the output end 606 of the injector 116 can be provided in various configurations. For example, the output end 602 of the injector protector 600 is shown in Figure 6A such that it extends outward toward the torch outlet relative to the output end 606 of the injector 116. In Figure 6B, the output end 602 of the injector protector 600 is shown to be substantially flush with the output end 606 of the injector 116 (for example, the output ends 602 and 606 terminate at substantially the same longitudinal position between the inlet end 128 and the outlet end 130 of the torch 102). In Figure 6C, the output end 602 of the injector protector 600 is shown to extend beyond the output end 606 of the injector 116 in the direction toward the torch outlet. Such a fitting position of the output end 606 of the injector 116 relative to the output end 602 of the injector protector 600 can provide protection for the output end 606 of the injector 116 from the plasma formed by the torch 102, thereby suppressing damage to the material of the injector 116 (e.g., platinum, sapphire, etc.) by the plasma, emission into the plasma (e.g., this can adversely affect the ICPMS background during analysis), or a combination of these.

[0031] Although the injector protector 600 is shown in Figures 6A to 6C as being formed as a substantially cylindrical tubular structure, the injector protector 600 is not limited to such a configuration. In embodiments, the injector protector 600 may include curved portions, flared portions, tapered portions, or a combination thereof, so as to fit, match, or otherwise surround a portion of the injector 116. For example, the injector protector 600 has a tapered portion 608 to fit a tapered injector 116, as shown in Figure 6D. The tapered injector protector 600 may have an output end 602 that is flush with or extends beyond the output end 606 of the injector 116, as shown with respect to Figures 6A to 6C. For example, Figure 6D shows an example of a torch 102 in which the output end 602 of the tapered injector protector 600 is inserted and positioned relative to the output end 606 of the injector 116.

[0032] In the embodiment, the torch 102 can facilitate the introduction of a gas flow between the injector protector 600 and the injector 116 to protect the output end 602 of the injector protector 600 from the plasma formed by the torch 102. For example, the torch 102 including a gas introduction sheath 700 coupled to the torch 102 is shown in Figures 7A and 7B. The gas introduction sheath 700 is configured to receive the input ends of the injector 116 and the injector protector 600 and includes a gas inlet port 702 configured to receive gas to be introduced into the annular space 704 between the injector protector 600 and the injector 116. The gas introduced into the gas inlet port 702 may include, but is not limited to, argon, nitrogen, or a combination thereof.

[0033] Generally, the outlet or outlet end of an ICP torch is typically the first part of the torch to be damaged during operation at low flow rates of cooling gas. As the torch outlet heats up and devitrifies, adjacent torch components distal to the outlet overheat (overhead) and begin to degrade, thus shortening the torch's lifespan. However, simply shortening the torch is not practical, and design constraints limit the available solutions. Many ICP and ICPMS systems require a torch long enough to isolate the plasma from the load coil and external RF plate during plasma ignition, and the torch must be long enough to avoid adverse effects on the plasma geometry or adverse effects from entrainment of external air. In embodiments, the torch 102 may include other features that protect it from the effects of proximity to the plasma formed by the torch 102.

[0034] For example, a torch 102 having a flare outlet 800 is shown in Figures 8A and 8B. The flare outlet 800 is formed by an outer tube 112 adjacent to the outlet end 130 of the torch 102, and can assist in low-gas-flow operation of the torch 102 while preventing damage to the torch 102 due to the plasma effect. The flare outlet 800 moves the outer tube 112 away from the plasma formed through the gas combination introduced into the torch (e.g., to the annular regions 118 and 132), and the aerosolized sample passes through it via the carrier gas through the injector 116. By positioning the end of the outer tube 112 away from the plasma, the outer tube 112 is further protected from the effects of the plasma, significantly reducing devitrification damage to the torch 102, but still providing a laminar flow environment for the cooling gas introduced into the annular region 118, enabling low-gas-flow operation of the torch 102 (e.g., with a cooling gas flow rate of less than approximately 12 L / min). The flare outlet 800 facilitates proper positioning within the ICP load coil, facilitates ignition (e.g., via the ignition port 802), and allows operation of the torch 102 under low cooling gas flow conditions (e.g., less than approximately 12 L / min) while maintaining the length of the torch 102 to effectively provide a short torch profile, while controlling the entrainment of external air during operation of the torch 102. Operation of the torch 102 provides reduced argon consumption, reduced power consumption (due to lower ionization energy), and at the same time avoids background interference or other contamination due to torch devitrification, and overall damage to the injector 116.

[0035] In this embodiment, the flare outlet 800 is formed downstream of the outlet end 804 of the inner tube 110 (i.e., toward the outlet end 130). For example, Figure 8B shows a torch 102, and the outer tube 112 has a substantially cylindrical shape, extending from the connection region 806 with the inner tube 110 to the flare region 808 downstream of the outlet end 804 of the inner tube 110. In the flare region 808, the outer tube 112 widens from a first tube width 810 to a second tube width 812 at the outlet end 130, positioning the end of the outer tube 112 away from the plasma formed by the torch 102. The difference between the first tube width 810 and the second tube width 812 may vary based on the overall dimensions of the torch 102. For example, in this embodiment, the second tube width 812 is about 10% to about 20% larger than the first tube width 810. In the embodiment, the transition between the first tube width 810 and the second tube width 812 is a constant increase. In the embodiment, the transition between the first tube width 810 and the second tube width 812 involves a non-linear increase in width. In the embodiment, the transition between the first tube width 810 and the second tube width 812 includes one or more sections having the same width. The flared region 808 generally defines a portion of the longitudinal length of the outer tube 112. For example, the flared region 808 may be about 4 percent to about 10 percent of the longitudinal length of the outer tube 112.

[0036] In the experimental example, two torches were subjected to the same operating conditions with the same low-cooling gas flow at an RF power of 1600 W for the same amount of time. The first torch 900, shown in Figure 9A, included a substantially cylindrical outlet end (i.e., a non-flared end). After the test period, the torch 900 had significant devitrification damage in the region 902 near the non-flared outlet end. The second torch 904, shown in Figure 9B, had a structure similar to that of an embodiment of the present disclosure. For example, the torch 904 included a flared outlet 800 formed by an outer tube, while maintaining the same dimensions and features of the inner tube and injector as provided in the torch 900. After the test period (i.e., the same time experienced by the first torch 900), the second torch 904 did not show the significant devitrification damage exhibited by the first torch 900, and showed almost no damage to the outer tube.

[0037] In another experimental example, the matrix stability of torch 102 was measured by analyzing samples in an ICPMS analysis system over a period of approximately 8 hours using torch 102 with a flare outlet of 800. Torch 102 was operated with 1200 W RF power and 13 L / min of cooling gas. For calibration, a 1% nitric acid blank, a 50 ppb spike containing 100 ppm Mg, Al, Ca, K, Fe, Na in 1% nitric acid, and a 100 ppb spike containing 100 ppm Mg, Al, Ca, K, Fe, Na in 1% nitric acid were used. Multiple samples were loaded with 100 ppm Mg, Al, Ca, K, Fe, Na in 1% nitric acid, and one sample run was performed for approximately 8 hours (sample-to-sample time was approximately 2 minutes, and analysis time was approximately 50 seconds). After 8 hours, Torch 102 showed no detectable signs of devitrification, and the relative standard deviation (RSD) values ​​were 1.9% to 2.9% for all species analyzed at 50 ppb (Bi, Ce, Cd, Co, Ga, In, Pb, U, Ho, Tb, Cu, Mg, Al, Fe) and 0.8% to 2.0% for all species analyzed at 100 ppb (Bi, Ce, Cd, Co, Ga, In, Pb, U, Ho, Tb, Cu, Mg, Al, Fe).

[0038] In another experimental example, a sample was analyzed using an ICPMS analysis system with a torch 102 having a flare outlet 800 to measure the amounts of Be, In, Ce, and U in a given sample. Torch 102 was operated with 1000W of RF power and 10L / min of cooling gas. The ICPMS daily tuning report showed an average RSD of 0.6% for all analyzed chemical species during a 4-day operating period.

[0039] In another experimental example, samples were analyzed using an ICPMS analysis system operating under NH3 cold plasma conditions with a platinum injector with an inner diameter of 2 mm and a perfluoroalkoxyalkane (PFA) nebulizer, using a torch 102 with an injector protector 600 (insertion configuration described in Figure 6C). In the first test, using 0.1 mL / min NH3 and 1.0 mL / min H2, the background equivalent concentration (BEC) of Si was 0.2 ppb (28 / 28). In the second test, using 0.1 mL / min NH3 and 1.5 mL / min H2, the background equivalent concentration (BEC) of Si was 0.1 ppb (28 / 28). In the third test, using 0.1 mL / min NH3 and 1.0 mL / min H2, the background equivalent concentration (BEC) of Si was 0.1 ppb (28 / 44). In the fourth test, 0.1 mL / min NH3 and 1.0 mL / min H2 were used, and the background econductivity (BEC) of Si was 0.5 ppb (28 / 28). In the fifth test, 0.1 mL / min NH3 and 1.5 mL / min H2 were used, and the background econductivity (BEC) of Si was 0.5 ppb (28 / 28). In the sixth test, 0.1 mL / min NH3 and 1.0 mL / min H2 were used, and the background econductivity (BEC) of Si was 0.3 ppb (28 / 44).

[0040] In another experimental example, torch 102 with an injector protector 600 (insertion configuration described in Figure 6C) was compared to a standard torch without an injector protector. Each torch was used for Si-28 background analysis in quadrupole ICPMS under the same conditions, but the main difference in the experiment was the injector protector 600. The detection limit (DL) of the standard torch without an injector protector was 0.35 ppb, and the background equivalent concentration (BEC) was 9.3 ppb. Torch 102 with an injector protector 600 showed a detection limit (DL) of 0.3 ppb at a background equivalent concentration (BEC) of 3.6 ppb, demonstrating a dramatic improvement in silicon background interference for use in the analysis of high-purity materials.

[0041] The torch 102 described herein may include all of the features described herein, or a combination of a subset of the features described herein. For example, the torch 102 may include multiple inlet ports 124 and / or inlet port 134 in combination with an injector protector 600 and in combination with a flare outlet 800. As another example, the torch 102 may include a single inlet port 124 and a single inlet port 134 in combination with an injector protector 600 and in combination with a flare outlet 800. As yet another example, the torch 102 may include multiple inlet ports 124 and / or inlet port 134 in combination with an injector protector 600 without a flare outlet 800. As yet another example, the torch 102 may include multiple inlet ports 124 and / or inlet port 134 in combination with a flare outlet 800 without an injector protector 600.

[0042] (Conclusion) While the subject matter of this patent has been described in terms specific to structural features and / or process operations, it should be understood that the subject matter defined in the attached claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as exemplary forms for carrying out the claims.

Claims

1. A tubular sample injector configured to receive an aerosolized sample into the interior defined by the walls of the tubular sample injector, An injector protector surrounding at least a portion of the tubular sample injector, An inner tube that surrounds at least a portion of the injector protector and forms a first annular space between the inner tube and the injector protector, the inner tube defining at least one inlet port for introducing an auxiliary gas into the first annular space, An inductively coupled plasma torch comprising: an outer tube surrounding at least a portion of the inner tube to form a second annular space, the outer tube defining at least one inlet port for introducing a cooling gas into the second annular space; The injector protector has a first portion that is tapered inward in the direction from the inlet end of the inductively coupled plasma torch toward the outlet end of the inductively coupled plasma torch, The inner tube has a second portion that extends outward toward the inner wall of the outer tube in the direction from the inlet end toward the outlet end, The inner surface of the second part faces the outer surface of the first part. Inductively coupled plasma torch.

2. The tubular sample injector, the injector protector, and at least one output end of the inner tube are positioned inside the outer tube. The inductively coupled plasma torch according to claim 1.

3. The output ends of the tubular sample injector, the injector protector, and the inner tube are each positioned inside the outer tube. The inductively coupled plasma torch according to claim 1.

4. The output terminal of the injector protector is substantially flush with the output terminal of the inner tube. The inductively coupled plasma torch according to claim 1.

5. The output end of the tubular sample injector extends beyond the output end of the injector protector. The inductively coupled plasma torch according to claim 4.

6. The output terminal of the tubular sample injector is substantially flush with the output terminal of the injector protector. The inductively coupled plasma torch according to claim 4.

7. The output end of the injector protector extends beyond the output end of the tubular sample injector. The inductively coupled plasma torch according to claim 4.

8. At least a portion of the tubular sample injector is tapered inward in a direction away from the inlet end and outlet end of the inductively coupled plasma torch. The inductively coupled plasma torch according to claim 1.

9. The inductively coupled plasma torch further comprises a gas introduction sheath coupled to the inlet end, The gas introduction sheath is configured to receive the input ends of the tubular sample injector and the injector protector in order to introduce gas between the tubular sample injector and the injector protector. The inductively coupled plasma torch according to claim 1.

10. The gas introduction sheath defines a gas inlet port configured to receive gas for introduction into a third annular space defined between the injector protector and the tubular sample injector. The inductively coupled plasma torch according to claim 9.

11. A tubular sample injector configured to receive an aerosolized sample into the interior defined by the walls of the tubular sample injector, An injector protector surrounding at least a portion of the tubular sample injector, An inner tube that surrounds at least a portion of the injector protector and forms a first annular space between the inner tube and the injector protector, the inner tube defining at least one inlet port for introducing an auxiliary gas into the first annular space, An outer tube that surrounds at least a portion of the inner tube and forms a second annular space, the outer tube defining at least one inlet port for introducing cooling gas into the second annular space, An inductively coupled plasma torch comprising: a gas introduction sheath coupled to the input ends of the tubular sample injector and the injector protector, respectively, for introducing gas between the tubular sample injector and the injector protector, the gas introduction sheath defining a gas inlet port configured to receive gas for introduction into a third annular space defined between the injector protector and the tubular sample injector; The injector protector has a first portion that is tapered inward in the direction from the inlet end of the inductively coupled plasma torch toward the outlet end of the inductively coupled plasma torch, The inner tube has a second portion that extends outward toward the inner wall of the outer tube in the direction from the inlet end toward the outlet end, The inner surface of the second part faces the outer surface of the first part. Inductively coupled plasma torch.

12. The tubular sample injector, the injector protector, and at least one output end of the inner tube are positioned inside the outer tube. The inductively coupled plasma torch according to claim 11.

13. The output ends of the tubular sample injector, the injector protector, and the inner tube are each positioned inside the outer tube. The inductively coupled plasma torch according to claim 11.

14. The output terminal of the injector protector is substantially flush with the output terminal of the inner tube. The inductively coupled plasma torch according to claim 11.

15. The output end of the tubular sample injector extends beyond the output end of the injector protector. The inductively coupled plasma torch according to claim 14.

16. The output terminal of the tubular sample injector is substantially flush with the output terminal of the injector protector. The inductively coupled plasma torch according to claim 14.

17. The output end of the injector protector extends beyond the output end of the tubular sample injector. The inductively coupled plasma torch according to claim 14.

18. At least a portion of the tubular sample injector and the injector protector is tapered inward in a direction away from the inlet end and the outlet end of the inductively coupled plasma torch. The inductively coupled plasma torch according to claim 11.

19. A method for operating an inductively coupled plasma torch, The aerosolized sample is introduced into the tubular sample injector of an inductively coupled plasma torch, wherein the inductively coupled plasma torch is An injector protector surrounding at least a portion of the tubular sample injector, An inner tube that surrounds at least a portion of the injector protector and forms a first annular space between the inner tube and the injector protector, the inner tube defining at least one inlet port for introducing an auxiliary gas into the first annular space, An outer tube that surrounds at least a portion of the inner tube and forms a second annular space, the outer tube defining at least one inlet port for introducing a cooling gas into the second annular space, for introducing an aerosolized sample, Introducing an auxiliary gas into the first annular space of the inductively coupled plasma torch through at least one inlet port of the inner tube, This includes introducing a cooling gas into the second annular space of the inductively coupled plasma torch at a flow rate of less than 12 L / min through at least one inlet port of the outer tube, The injector protector has a first portion that is tapered inward in the direction from the inlet end of the inductively coupled plasma torch toward the outlet end of the inductively coupled plasma torch, The inner tube has a second portion that extends outward toward the inner wall of the outer tube in the direction from the inlet end toward the outlet end, The inner surface of the second part faces the outer surface of the first part. method.

20. The further includes introducing a third gas into a third annular space defined between the injector protector and the tubular sample injector. The method according to claim 19.

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