User replaceable ablation cell interface for changing la-icp-ms peak width

Abstract

In one embodiment, a laser ablation system can include a laser ablation chamber and at least one pair of particle collection-to-conveyance duct interfaces. The laser ablation chamber can be configured to ablate a sample or another material, and the laser ablation chamber can include a laser unit. The at least one pair of particle collection-to-conveyance duct interfaces can be configured to aggregate the ablated sample and direct the ablated sample to an analysis unit. A selected particle collection-to-conveyance duct interface can be received by the laser ablation chamber directly above the laser unit. The at least one pair of particle collection-to-conveyance duct interfaces can be configured to be interchangeable with one another.

Description

[0001] Related applications

[0002] This application claims domestic priority to U.S. Provisional Patent Application No. 62 / 959,865, filed January 10, 2020, entitled “User Exchangable Ablation Cell Interface to Alter LA-ICP-MS Peakwidths”. Background Technology

[0003] Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) or laser ablation inductively coupled plasma emission spectroscopy (LA-ICP-OES) can be used to analyze the composition of targets (e.g., solid or liquid targets). Typically, the target sample is provided to the analytical system in the form of an aerosol (i.e., a suspension consisting of solid particles and possibly liquid particles and / or vapors in a carrier gas such as helium). This sample is typically produced by arranging the target within a laser ablation chamber, introducing a carrier gas flow within the chamber, and ablating a portion of the target using one or more laser pulses to generate a plume containing particles and / or vapors suspended in the carrier gas, either ejected from the target (hereinafter referred to as the “target”). The target, entrained in the flowing carrier gas, is delivered to the analytical system via a delivery conduit leading to an ICP torch, where it is ionized. The plasma containing ionized particles and / or vapors is then analyzed by an analytical system such as MS, QES, isotope ratio mass spectrometry (IRMS), or electrospray ionization (ESI) systems. Attached Figure Description

[0004] This detailed description is illustrated with reference to the accompanying drawings.

[0005] Figure 1 This is a front isometric view of a laser ablation chamber for use with a laser ablation spectroscopy measurement system, according to an exemplary embodiment of the present disclosure.

[0006] Figure 2 It is used for with Figure 1 Top-view isometric partial view of the laser ablation chamber, which is used in conjunction with the first particle collection section to the delivery pipe interface.

[0007] Figure 3 It is used for with Figure 1 Top-view isometric partial view of the laser ablation chamber, which is used in conjunction with the second particle collection section to the delivery pipe interface. Detailed Implementation

[0008] Several aspects of this disclosure will be described more fully below with reference to the accompanying drawings, which form a part of it and illustrate exemplary features by way of illustration. However, these features may be embodied in many different forms and should not be construed as limited to the combinations described herein; rather, these combinations are provided so that this disclosure will be exhaustive and complete and will fully convey its scope.

[0009] Overview

[0010] Different applications of LA-ICP-MS may require different aerosol delivery capabilities, which can be determined by the ablation chamber (around the ablation site), the delivery area (the connecting pipe to the ICP-MS), and / or even the gas flow geometry within the ICP itself. For example, "batch analysis" applications may require a very stable particle flow, where particles generated by one laser pulse overlap with particles generated by subsequent pulses during delivery. For typical laser frequencies used, this can be achieved with a peak width (primarily due to the rinsing time) of around 1 second. The result is a more uniform aerosol flow and a more stable signal on the ICP-MS. To obtain such a sustained peak width, the aerosol may be subjected to low gas flow velocity conditions where diffusion can occur and some dead volume, which has the effect of broadening the peak.

[0011] When analysts need to spatially interrogate samples, as is the case in elemental imaging (lateral profiling) and depth profiling, it is essential to avoid particle mixing caused by subsequent laser pulses, as spatial resolution is compromised in this way. Typically, for such imaging applications, a total peak width in the 1–100 ms region is ideal; shorter peak widths enable the possibility of higher spatial resolution, which can be achieved by minimizing dead volume and transporting aerosols at high gas flow rates.

[0012] Ablation chamber and delivery technologies have been optimized for "batch analysis" or "spatial analysis" in the past. Ablation chambers for batch analysis already have dead volumes designed to capture aerosols but allow some diffusion. Furthermore, the delivery conduit has a large inner diameter (e.g., 4 mm) to allow diffusion during transport, thus enabling the desired mixing / homogenization levels. Aerosols can be deposited into TCP torches, which in turn have a fairly large injector diameter, further contributing to achieving the desired diffusion levels.

[0013] Ablation chambers optimized for space operations typically eliminate / reduce any dead volume and attempt to entrain aerosols very quickly into the delivery area to minimize diffusion. Delivery ducts typically have small inner diameters (e.g., <2 mm) to facilitate high gas flow velocities and minimize diffusion and peak broadening. Narrow-diameter ducts extend as deep as possible into the ICP to similarly minimize "in-torch" diffusion.

[0014] A number of problems need to be overcome. One problem is that these different requirements often necessitate different ablation chambers. Converting the entire ablation chamber for different applications is not an ideal solution because it requires multiple units (which are expensive) and the conversion can be complex and time-consuming. In addition to the fact that different applications often require different ablation chambers, existing technologies typically require a consistent variation in the diameter of the delivery pipe, which does not provide the required level of control or the required magnitude of variation (e.g., typically not from 1 ms to 1 s (second)) and / or the use of inserts to “block” and minimize any dead volume in the ablation chamber—that is, the dead volume in the second volume (sometimes called the cup) designed to capture aerosols and guide them to the delivery pipe. Furthermore, the use of such inserts does not provide the required level of variation because a much more drastic change is required in the design of the second volume (or cup), which is practically impossible to achieve with inserts. The Helex chamber provided by Teledyne CETAC is a good example of this, and they offer a variety of inserts for their cups. However, such inserts can only change the peak width from a few milliseconds to hundreds of milliseconds at most.

[0015] In view of these issues, one embodiment of this system provides a single ablation chamber designed to allow the user / analyst to switch between two or more configurations / modes by simply replacing the entire particle collection-to-delivery interface relative to the ablation chamber. For example, one particle collection-to-delivery interface can be used to facilitate a rapid / imaging mode, where the aerosol is quickly entrained into a delivery area (tube) with a narrow inner diameter. Another particle collection-to-delivery interface can be used to facilitate an analytical mode, in which the interface is used to entrain the aerosol into a standard cup with a dead volume (e.g., a few milliliters (ml)) before entering a delivery area with a wider inner diameter. The interface is a complete component and can be converted within minutes. It will be understood that other interfaces facilitating other modes can be employed, provided they are compatible with the ablation chamber (e.g., overall size / shape; connection location).

[0016] Secondly, a significant challenge in utilizing high-speed LA-ICPMS plume collection is controlling the ablation surface and the sample leading to the collection orifice. The interaction between the airflow dynamics around the ablation site and the surface of the ablation leading to the collection orifice has been observed. If the distance is large, the ablation plume's travel distance and travel time can be increased in the low-velocity region between the ablation and collection channels. Notably, the LA-ICPMS signal width is directly driven by the total transport time due to the diffusion of nanoparticles in the gas suspension. If the distance is too small, it will prevent the total flow rate from reaching the output orifice and will also reduce the absorption efficiency of the particle plume.

[0017] Work performed using this system has shown that the ideal distance from the sample surface to the collection well is approximately 100 to 300 micrometers (μm). This distance can be optimized during setup and maintained during LA-ICPMS experiments.

[0018] Another challenge lies in bringing the sample surface close to the output aperture. In a typical triaxial system, the X and Y axes are specifically used to move the sample under a laser objective that moves in the Z-axis plane to obtain an adjustable focus position for samples with varying heights. The geometry of the sample-to-sniff distance means that if a given sample height varies by more than a few hundred micrometers, it may inadvertently scrape the corresponding sample below and through the collection aperture during patterning, thereby damaging the sample.

[0019] Regarding standard slow collection, when introducing the ability to switch from high-speed to slow plume collection to users, the distance from the sample to the collection orifice needs to be considered. Due to differences in collection orifice geometry, slow plume collection requires different and larger distances between the sample / ablation surface and the collection orifice. These requirements for different sample surface heights may necessitate not only changing the sample-to-output distance but also altering the laser focusing surface.

[0020] Exemplary Implementation

[0021] Figure 1-3A laser ablation system 100 according to this disclosure is illustrated. In one embodiment, the laser ablation system 100 may include a laser ablation chamber 105 for ablating a sample or other material, a laser unit 108, and a set of interchangeable particle collection-to-delivery conduit interfaces 110A, 110B. The laser ablation chamber 105 may be designed such that a user / analyst can change between a pair of configurations / modes, for example, by simply replacing the entire particle collection-to-delivery conduit interface 110A, 110B. The laser unit 108 of the laser ablation chamber 105 may be housed within the laser ablation chamber 105. Selected particle collection-to-delivery conduit interfaces 110A, 110B may be received and mounted in the laser ablation chamber 105 to be positioned directly above the laser unit 108 (e.g., a laser diode and associated electronics). In one embodiment, the particle collection-to-delivery conduit interfaces 110A, 110B may be received between the laser ablation chamber 105 and the laser unit 108. The laser unit 108 can thus be configured to ablate a given sample to be collected by a given particle collection section to delivery conduit interfaces 110A, 110B (e.g., thereby generating a laser and / or ablation plume). The given particle collection section to delivery conduit interfaces 110A, 110B can then (via fluid connection) guide particles associated with the sample to be ablated to an analysis unit (not shown). In one embodiment, interfaces 110A, 110B are complete components and can be converted within minutes (e.g., easily converted to another interface). In one embodiment, the first interface 110A may have a different distance from the sample ablation surface to its associated collection orifice compared to the second interface 110B.

[0022] Figure 1 The laser ablation chamber 105, equipped with a fast / imaging interface 110A, is shown. Figure 2 A close-up of the fast / imaging interface 110A is shown. The analysis mode (slower) interface 110B is shown positioned in front of and separate from the laser ablation chamber 105, wherein interface 110B is interchangeable with interface 110A. A close-up of the analysis mode interface 110B is shown. Figure 3 In one embodiment, a given particle collector-to-delivery pipe interface (e.g., 110A) is optimized for sampling the laser plume at close range, thereby enabling high-speed signal extraction. In another embodiment, a given particle collector-to-delivery pipe interface (e.g., 110B) is optimized for slower sampling of the ablation plume, thereby enabling slower but more stable signal extraction (e.g., thus facilitating analysis modes). It will be understood that other interchangeable interface units may be used depending on the situation, as long as those with similar "footprint" and connection points to interfaces 110A and 110B are acceptable.

[0023] Regarding a second aspect of this disclosure, the hardware system can allow control over the distance between the sample and the collection orifice within the chamber, and the laser focusing surface (e.g., the sample ablation surface). The associated software user interface design can automatically change this distance between the sample ablation surface and the collection orifice when the user selects a different collection mode (e.g., when switching between interfaces 110A and 110B). The software system can allow the user to perform model planning with a larger sample-to-collection-orifice distance (e.g., as indicated by the switching between interfaces 110A and 110B) and when in high-speed mode, then automatically move the sample and laser surface until an ideal high-speed position is achieved relative to the output orifice. The software system can easily adjust the sample / ablation surface-to-collection-orifice distance for high-speed mode by selectively changing the tandem laser focus and a distance equal to that of the ablation surface. This second aspect may be useful when used with a user-changeable second volume (e.g., as when changing interfaces 110A and 110B).

[0024] The laser ablation system 100 can be controlled by a computing system with a processor configured to operate from a non-transitory carrier medium (e.g., a storage medium such as a flash drive, hard disk drive, solid-state drive, SD card, optical disk). The computing system can be connected to various components of the analysis system via direct connection or via one or more network connections (e.g., a local area network (LAN), a wireless local area network (WAN or WLAN), one or more hub connections (e.g., a USB hub), etc.). For example, the computing system can be communicatively coupled (e.g., hardwired or wirelessly coupled) to controllable elements of the laser ablation system 100 (e.g., the laser ablation chamber 105, the laser unit 108, and / or the particle collection section to the delivery pipe interfaces 110A, 110B). When executed by the processor, program instructions can cause the computing system to control the laser ablation system 100. In one embodiment, the program instructions form at least a portion of a software program executed by the processor.

[0025] The processor provides processing capabilities to a computing system and may include any number of processors, microcontrollers, or other processing systems, as well as resident or external memory for storing data and other information accessed or generated by the computing system. The processor is not limited by the materials forming it or the processing mechanisms employed therein, and therefore can be implemented via semiconductors and / or transistors (e.g., integrated circuits (ICs)).

[0026] Non-transitory carrier media are examples of device-readable storage media that provide storage functionality to store various data associated with the operation of a computing system, such as software programs, code segments, or program instructions or other data, to instruct the processor and other components of the computing system (e.g., the software system described above for controlling various operational aspects of the laser ablation system 100) to perform the techniques described herein. The carrier media may be integrated with a processor, a standalone memory, or a combination of both. The carrier media may include, for example, removable and non-removable storage elements, such as RAM, ROM, flash memory (e.g., SD card, mini SD card, micro SD card), magnetic, optical, USB storage devices, etc. In embodiments of the computing system, the carrier media may include removable ICC (integrated circuit card) memory, such as a SIM (Subscriber Identity Module) card, USIM (Universal Subscriber Identity Module) card, UICC (Universal Integrated Circuit Card), etc.

[0027] The computing system may include one or more displays to show information to a user of the computing system. In embodiments, the display may include a CRT (cathode ray tube) display, an LED (light-emitting diode) display, an OLED (organic LED) display, an LCD (liquid crystal diode) display, a TFT (thin-film transistor) LCD display, an LEP (light-emitting polymer) or PLED (polymer light-emitting diode) display, etc., configured to display text and / or graphical information, such as a graphical user interface. The display may be backlit, allowing it to be viewed in dark or other low-light environments. The display may be equipped with a touchscreen to receive input from the user (e.g., data, commands, etc.). For example, the user may operate the computing system by touching the touchscreen and / or by performing gestures on the touchscreen. In some embodiments, the touchscreen may be a capacitive touchscreen, a resistive touchscreen, an infrared touchscreen, a combination thereof, etc. The computing system may also include one or more input / output (I / O) devices (e.g., a keypad, buttons, wireless input devices, a fingerwheel input device, a trackpoint input device, etc.). The I / O devices may include one or more audio I / O devices, such as a microphone, a speaker, etc.

[0028] The computing system may also include a communication module representing communication functions, allowing the computing device to send / receive data between different devices (e.g., components / peripherals) and / or over one or more networks. This communication module may represent a variety of communication components and functions, including, but not limited to: browsers; transmitters and / or receivers; data ports; software interfaces and drivers; network interfaces; data processing components; etc.

[0029] One or more networks represent various communication paths and network connections that can be used individually or in combination to communicate between components of a given laser ablation-based analysis system. Thus, one or more networks can represent communication paths implemented using a single network or multiple networks. Furthermore, one or more networks represent various envisioned types of networks and connections, including, but not limited to: the Internet; intranets; personal area networks (PANs); local area networks (LANs) (e.g., Ethernet); wide area networks (WANs); satellite networks; cellular networks; mobile data networks; wired and / or wireless connections; etc. Examples of wireless networks include, but are not limited to: networks configured to communicate according to: one or more standards of the Institute of Electrical and Electronics Engineers (IEEE), such as the 802.11 or 802.16 (Wi-Max) standards; Wi-Fi standards issued by the Wi-Fi Alliance; Bluetooth standards issued by the Bluetooth Special Interest Group; etc. Wired communication, such as via Universal Serial Bus (USB), Ethernet, serial connections, etc., is also envisioned.

[0030] The computing system is described as including a user interface, which may be stored in memory (e.g., a carrier medium) and executed by a processor. The user interface represents the functionality to display information and data to a user of the computing system via a display control. In some embodiments, the display may not be integrated into the computing system, but may instead be connected externally using a Universal Serial Bus (USB), Ethernet, serial connection, etc. The user interface may provide functionality to allow a user to interact with one or more applications of the computing system by providing input via a touchscreen and / or I / O devices (e.g., sample identity, desired dilution factor, standard identity, eluent identity / location, fluid additive flow rate, etc.). For example, the user interface may cause the generation of an application programming interface (API) to expose functionality to an online dilution control module to configure the application for display on a monitor or in combination with another display. In embodiments, the API may further expose functionality to configure the online dilution control module to allow a user to interact with the application by providing input via a touchscreen and / or I / O devices, thereby providing the desired dilution factor for analysis.

[0031] In an implementation, the user interface may include a browser (e.g., for implementing the functionality of an online dilution control module). The browser enables the computing device to display and interact with content such as web pages on the World Wide Web or web pages provided by web servers in a private network. The browser can be configured in various ways. For example, the browser may be configured as an online dilution control module accessed by a user interface. The browser may be a web browser suitable for use by fully-resourced devices with ample memory and processor resources (e.g., smartphones, personal digital assistants (PDAs), etc.).

[0032] Generally, any functionality described herein can be implemented using software, firmware, hardware (e.g., fixed logic circuitry), manual processing, or a combination of these implementations. As used herein, the terms "module" and "function" generally refer to software, firmware, hardware, or a combination thereof. For example, communication between modules in a given laser ablation-based analysis system can be wired, wireless, or some combination thereof. For example, in a software implementation, a module can represent executable instructions that, when executed on a processor (e.g., the processor described herein), perform a specified task. This program code can be stored in one or more device-readable storage media, examples of which are non-transitory carrier media associated with a computing system.

[0033] Although the subject has been described in language specific to structural features and / or methodological behaviors, it will be understood that the subject is not necessarily limited to the specific features or behaviors described above. Rather, the specific features and behaviors described above are disclosed as examples.

Claims

1. A laser ablation system, comprising: A laser ablation chamber configured to ablate a sample or other material, the laser ablation chamber being in optical communication with a laser unit; and At least one pair of particle collection section to delivery pipe interfaces are configured to collect ablated samples from the laser ablation chamber and guide the ablated samples to the analysis unit. Selected particle collection section to delivery pipe interfaces are configured to be positioned above the laser ablation site within the laser ablation chamber or to be received between the laser ablation chamber and the laser unit. At least one pair of particle collection section to delivery pipe interfaces are configured to be interchangeable to change the collection mode of the laser ablation chamber.

2. The laser ablation system as described in claim 1, wherein, The selected particle collection section has a different geometry at the delivery pipe interface, and the geometry is optimized for different applications.

3. The laser ablation system as described in claim 1, wherein, The first particle collection section to delivery pipe interface and the second particle collection section to delivery pipe interface in the at least one pair of particle collection section to delivery pipe interfaces have similar space occupation and connection point layout to facilitate their interchangeability.

4. The laser ablation system as described in claim 2, wherein, Each particle collection unit has a similar footprint and connection point layout to the delivery pipe interface, so that it can be interchangeably mounted above the portion of the laser ablation chamber used for laser ablation of the sample or other material in the laser ablation chamber.

5. The laser ablation system as described in claim 3 or 4, wherein, Each particle collection unit and its delivery pipe interface is a complete assembly.

6. The laser ablation system as described in claim 1 or 2, wherein, A given particle collection section to delivery pipe interface is optimized for sampling the laser plume at close range, thereby enabling high-speed signal extraction.

7. The laser ablation system as described in claim 1 or 2, wherein, A given particle collection section to delivery pipe interface is optimized for slower sampling of the ablation plume, resulting in slower but more stable signal extraction.

8. The laser ablation system as described in claim 1 or 2, wherein, The laser ablation chamber is configured to allow control of at least one of the distance between the sample ablation surface and the collection hole within the laser ablation chamber and the position of the sample ablation surface associated with the laser unit by switching the selected particle collection section to the delivery pipe interface between the at least one pair of particle collection sections to the delivery pipe interface.

9. The laser ablation system as described in claim 1 or 2, wherein, The first particle collection point to delivery pipe interface and the second particle collection point to delivery pipe interface of the at least one pair of particle collection points to delivery pipe interfaces have different distances from the sample ablation surface to their associated collection holes.

10. The laser ablation system as described in claim 1 or 2, wherein, The laser ablation chamber is also configured to automatically change the distance between the sample ablation surface inside the laser ablation chamber and the collection hole when the user selects to switch collection modes.

11. The laser ablation system as described in claim 10, wherein, When switching between different particle collection sections and delivery pipe interfaces, a prompt will appear indicating the change in collection mode.

12. The laser ablation system as described in claim 1, wherein, The laser ablation chamber is configured to selectively adjust the distance from the sample ablation surface to the collection hole.

13. A method using a laser ablation system, comprising: Provides a laser ablation chamber configured to ablate a sample or other material, the laser ablation chamber being in optical communication with a laser unit, the laser ablation chamber receiving a first particle collection unit to a delivery pipe interface directly above the laser ablation site associated with the laser ablation chamber; and The first particle collection unit to delivery pipe interface is replaced by a second particle collection unit to delivery pipe interface, the first particle collection unit to delivery pipe interface being configured to be removably connected to the laser ablation chamber and interchangeable with the second particle collection unit to delivery pipe interface to change the collection mode of the laser ablation chamber.

14. The method of claim 13, wherein, A given particle collection unit to delivery pipe interface is optimized to sample the laser plume at close range for high-speed signal extraction, or optimized to sample the ablation plume more slowly for slower and more stable signal extraction.

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