Film-based purge gas and sample transfer for laser ablation sample processing

Abstract

Systems and methods are described for transferring gas from an ablation unit to an inductively coupled plasma analysis system via a gas exchange membrane transfer line to exchange the gas introduced to the ablation unit with a purge gas. System embodiments include, but are not limited to: a laser ablation unit configured to generate a sample transfer stream by laser ablation of a sample and introduction of a carrier gas for flowing the ablated sample from the laser ablation unit; an inductively coupled plasma analysis device configured to measure one or more analytes in the sample transfer stream; and a gas exchange membrane transfer line fluidly coupled between the laser ablation unit and the inductively coupled plasma analysis device, the gas exchange membrane transfer line configured to displace a gas in the sample transfer stream with a purge gas via gas exchange across a membrane of the gas exchange membrane transfer line.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of 35 U.S.C. §119(e) of U.S. Provisional Application Serial No. 63 / 319,846, filed on March 15, 2022, and entitled “MEMBRANE-BASED PURGE GAS AND SAMPLE TRANSFER FOR LASER ABLATION SAMPLE PROCESSING.” The entire contents of U.S. Provisional Application Serial No. 63 / 319,846 are incorporated herein by reference.

[0003] background

[0004] Laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) techniques and laser ablation inductively coupled plasma optical emission spectroscopy (LA-ICP-OES) techniques can be used to analyze the composition of a target (e.g., a solid or liquid target material). Typically, a sample of the target is provided to an analysis system in the form of an aerosol (i.e., a suspension of solid and possibly liquid particles and / or vapors in a carrier gas (e.g., helium)). The sample is typically generated by placing the target within a laser ablation chamber; introducing a flow of carrier gas within the chamber; and ablating a portion of the target using one or more laser pulses to produce a plume containing particles and / or vapors ejected or otherwise generated from the target suspended within the carrier gas. Entrained in the flowing carrier gas, the target material is transported to the analysis system via a transport conduit to an inductively coupled plasma (ICP) torch where the target material is ionized.

[0005] The plasma containing ionized particles and / or vapors is then analyzed by an analytical system, such as a mass spectrometry (MS) system, an optical emission spectroscopy (OES) system, an isotope ratio mass spectrometry (IRMS) system, or an electrospray ionization (ESI) system. For example, ICP spectroscopy is an analytical technique commonly used to determine the concentration and isotope ratio of trace elements in a liquid sample. ICP spectroscopy uses an electromagnetically generated partially ionized argon plasma that reaches a temperature of about 7000K. When the sample is introduced into the plasma, the high temperature causes the sample atoms to become ionized or emit light. Since each chemical element produces a characteristic mass spectrum or emission spectrum, measuring the emitted mass or light spectrum allows the elemental composition of the original sample to be determined. Summary of the invention

[0006] Systems and methods are described for transferring sample gas from an ablation cell to an inductively coupled plasma analysis system via a gas exchange membrane transfer line to exchange gas introduced into the ablation cell with a sweep gas without extinguishing a plasma used by an analysis system for measuring analytes in the sample gas. System embodiments include, but are not limited to: a laser ablation cell configured to generate a sample transfer stream by laser ablation of a sample and introduction of a carrier gas for flowing the ablated sample from the laser ablation cell; an inductively coupled plasma analysis device configured to measure one or more analytes in the sample transfer stream; and a gas exchange membrane transfer line fluidly coupled between the laser ablation cell and the inductively coupled plasma analysis device, the gas exchange membrane transfer line configured to replace gas in the sample transfer stream with a sweep gas via gas exchange across a membrane of the gas exchange membrane transfer line.

[0007] One method embodiment includes, but is not limited to: transferring a sample transfer stream comprising a plurality of sample particles and at least one gas from a laser ablation system to a gas exchange membrane transfer line; introducing a sweep gas into the gas exchange membrane transfer line; separating at least a portion of the at least one gas from the plurality of sample particles via exchange with at least a portion of the sweep gas; and transferring the sample transfer stream through the gas exchange membrane transfer line to an inductively coupled plasma analysis device.

[0008] System embodiments include, but are not limited to, a laser ablation system configured to generate a sample transfer stream by laser ablation of a sample and introduction of a carrier gas for flowing the ablated sample from the laser ablation system; an inductively coupled plasma analysis device configured to measure one or more analytes in the sample transfer stream; and a gas exchange membrane transfer line fluidly coupled between the laser ablation system and the inductively coupled plasma analysis device, the gas exchange membrane transfer line configured to replace gas in the sample transfer stream with a sweep gas via gas exchange across a membrane of the gas exchange membrane transfer line.

[0009] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description section. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The detailed description section is described with reference to the accompanying drawings.

[0011] Figure 1 is a schematic illustration of a system for controlling a flow of a purge gas introduced into an ablation cell between samples according to an example embodiment of the present disclosure.

[0012] Figure 2 is an illustration of a gas exchange membrane coupled between a laser ablation system and an analysis system to replace a sample gas or a purge gas with a sweep gas according to an example embodiment of the present disclosure.

[0013] Figure 3 During the gas exchange process Figure 2 Schematic illustration of a gas exchange membrane.

[0014] Figure 4 is a graph of the strength of nitrogen added versus the amount of nitrogen to the gas exchange membrane, used to provide a nitrogen calibration curve.

[0015] Figure 5 is a graph of the rate of nitrogen detected by the analysis system after gas exchange through the gas exchange membrane versus the rate of nitrogen added before the gas exchange membrane. DETAILED DESCRIPTION

[0016] Overview

[0017] Laser ablation is a sampling method that uses a focused pulsed laser beam in a laser ablation unit to convert a portion of a solid or liquid sample from a target object into an aerosol phase that is transported on a gas stream to an analyzer such as an inductively coupled plasma mass spectrometer (ICPMS). Multiple laser pulses can be used to ablate different areas of the sample to generate sufficient signal and ensure that a representative sample is collected for analysis.

[0018] The laser ablation system can utilize automated sample loading techniques to facilitate automated processing of multiple samples for a single laser ablation cell. For example, the laser ablation system can include a sample loading system (e.g., a sample turntable) to accommodate multiple samples and to sequentially introduce the samples into the laser ablation cell to generate separate ablation samples. For example, the sample turntable can be rotated to bring a given sample to a position adjacent to and below the laser ablation cell. A piston located below the turntable can vertically lift a given sample into or against the laser ablation cell and hold the sample in place during laser ablation sampling. After the ablated target material is transferred from the laser ablation cell to the analyzer, the piston can lower the sample, wherein the turntable positions the next sample adjacent to and below the laser ablation cell. During the transition between samples, atmospheric gas can enter the exposed laser ablation cell, such as wherein the lowering of the piston exposes a bottom portion of the laser ablation cell to the atmosphere or to entrained atmospheric gas present within the laser ablation system. If atmospheric gases are delivered to the analyzer, the plasma of the ICP torch may be extinguished, resulting in downtime of the ICP analyzer during the subsequent reignition of the ICP torch and performance of any recalibration or stabilization techniques, which in turn reduces sample throughput and increases operating costs for the ICP analyzer (e.g., due to increased nebulizer gas usage, power requirements, etc.).

[0019] One option to prevent atmospheric gases from entering the ICP torch is to utilize a pinch valve to selectively choose the path for the gas from the laser ablation unit to follow. For example, a transfer line from the laser ablation unit can be split into two gas lines made of a pliable / flexible material and enter the pinch valve. A first gas line connects the laser ablation unit with the ICP torch, and a second gas line connects the laser ablation unit with a purge location (e.g., a vent, a waste section, etc.). During transitions between samples, the pinch valve pinches the first gas line closed by compressing the flexible tubing to prevent atmospheric gases from reaching the ICP torch, while the second gas line remains open to purge atmospheric gases. During sampling, the pinch valve opens the first gas line by compressing the flexible tubing and pinches the second gas line closed to prevent sample gas from being purged, while allowing the sample to be transferred to the ICP torch through the first gas line.

[0020] However, pinch valves introduce a number of drawbacks to the operation of laser ablation systems due to the frequent changes in the inner diameter of the tubing conveyed between the laser ablation cell and the ICP analyzer. For example, the opening and closing operation of the pinch valve may be unreliable due to sticking of the flexible tubing between the opening / closing operations (e.g., the inner wall of the tubing sticks to itself), due to deformation of the flexible tubing over time (e.g., hardening of the flexible tubing material), or other reasons. Sticking of the tubing or other tubing deformations may increase over time due to mechanical failure or tubing aging. In addition, the tubing may be susceptible to clogging, where sample or atmospheric particles may accumulate at the pinch point, which may affect the consistency of sample analysis by the ICP analyzer and require frequent maintenance or replacement of the tubing, which is often only noticed after a sample program failure is sensed, which may result in reprocessing of the sample after the maintenance of the tubing and the time loss associated therewith. Such mechanical problems with the pinch valve may lead to problems such as variable cell pressure of the laser ablation cell during sample processing and variable sensitivity of the ICP analyzer used to measure analytes in the sample gas transferred from the laser ablation cell.

[0021] Accordingly, in one aspect, the present disclosure relates to systems and methods for transferring gas from a laser ablation system to an inductively coupled plasma analysis system via a gas exchange membrane transfer line to exchange the gas introduced into the laser ablation system with a sweep gas without extinguishing the plasma used by the analysis system for measuring analytes in the sample gas. The gas exchange membrane transfer line is fluidly connected between the laser ablation system (or a portion thereof, for example if a laser ablation unit is employed) and the analysis system and includes a tube formed by a gas exchange membrane (e.g., a polytetrafluoroethylene (PTFE) membrane) contained within an outer tube. A sweep gas (e.g., Ar gas) is introduced into one end of the transfer line into an annular space between the tubes. A sample transfer stream is introduced into the interior of the gas exchange membrane tube at the end of the transfer line opposite to the introduction of the sweep gas, so that the sweep gas and the sample transfer stream flow in opposite directions. In an embodiment, the flow rate of the sweep gas can be controlled by a mass flow controller (MFC).

[0022] Gases present in the sample transfer stream are transferred through the membrane into the annular space between the tubes (e.g., due to balancing forces) and are ultimately removed from the transfer line for subsequent disposal through an exhaust. A purge gas (e.g., supplied via the MFC) is transferred from the annular space through the membrane and into the sample transfer stream. Thus, the sample transfer stream has all or substantially all of the previous gas (e.g., nitrogen, purge gas, atmospheric gas, etc.) replaced with a purge gas (e.g., Ar) prior to transfer of the sample transfer stream into the analysis system. This allows a purge gas to be added to the ablation cell and the entire flow path to be purged without physically clamping or constraining the system.

[0023] Example Implementations

[0024] Overall reference Figures 1 to 5 , according to an example embodiment of the present disclosure, system 100 is shown for transferring gas from a laser ablation system to an inductively coupled plasma analysis system via a gas exchange membrane transfer line to exchange gas introduced into the laser ablation system with a sweep gas. System 100 generally includes a laser ablation system 102 in fluid communication with each of a gas exchange membrane transfer line ("transfer line 104") and an analysis system 106. Laser ablation system 102 may include a laser ablation cell or other chamber that holds a sample while a focused pulsed laser beam converts a portion of the sample into an aerosol phase that is transported on a gas stream into transfer line 104. Transfer line 104 introduces a sweep gas to exchange with gas used by laser ablation system 102 to transfer a sample from the laser ablation system or to purge the atmosphere introduced during sample transfer. The flow of material from the laser ablation system 102 to the analysis system 106 through the transfer line 104 is referred to herein as a "sample transfer stream," wherein the composition of the sample transfer stream may vary over the length of the transfer line 104 due to the exchange of sweep gas with gases present in the laser ablation system (e.g., carrier gas, atmospheric gas, purge gas, etc.). Example gases present in the laser ablation system during the sample transfer or purge cycle include, but are not limited to, helium, nitrogen, carbon dioxide, oxygen, etc. Example purge gases include, but are not limited to, argon. Thus, as the sample is transferred to the analysis system 106, the sample transfer stream may include ablation sample, carrier gas, atmospheric gas, purge gas, and sweep gas of varying composition, wherein as the sample transfer stream travels through the transfer line 104, more sweep gas replaces gas transferred from the laser ablation system 102. The transfer line 104 also fluidly couples the laser ablation system 102 with the analysis system 106, which in embodiments is an inductively coupled plasma analysis system such as an ICP-MS system, ICP-OES, etc., for measuring one or more analytes in the sample transfer stream.

[0025] Transfer line 104 is Figure 2 and Figure 31 and 2 as including an outer tube 200 surrounding an inner tube 202, the outer tube being formed of a gas impermeable material, the inner tube being composed of a gas exchange membrane material. In an embodiment, the gas exchange membrane material is a polytetrafluoroethylene (PTFE) membrane, however the transfer line 104 is not limited to such a material and may include an alternative or additional material suitable for displacement of a sweep gas while being substantially impermeable to sample particles. The sample transfer flow is introduced from the laser ablation system 102 into the interior of the inner tube 202 at a first end 204 of the transfer line 104 and transferred through the transfer line 104 to a second end 206 of the transfer line 104 that is fluidly coupled to the analysis system 106. The sweep gas is introduced into an annular region 208 between the outer tube 200 and the inner tube 202 and transferred through the transfer line 104 toward the first end 204. In an embodiment, the sweep gas is introduced into the transfer line 104 via a sweep gas inlet 210 adjacent to the second end 206 of the transfer line 104 and removed from the transfer line 104 via a sweep gas outlet 212 adjacent to the first end 204 of the transfer line 104. However, for longer transfer lines 104 (e.g., transfer lines greater than six feet), the sweep gas inlet 210 may be positioned away from the second end 206 and closer to the middle of the transfer line 104, wherein the length of the transfer line 104 ensures that sufficient residence time is provided for the sweep gas to exchange into the sample transfer stream. In an embodiment, the flow rate of the sweep gas is managed by a mass flow controller (MFC) so that it is introduced into the sweep gas inlet 210 at a precisely controlled flow rate.

[0026] Although the transfer line 104 is described herein as including a substantially coaxial arrangement configuration of the inner tube 202 and the outer tube 200 for providing the annular region 208 therebetween, the present disclosure is not limited to such a configuration configuration for the transfer line 104. For example, the inner tube 202 and the outer tube 200 may be offset such that the region therebetween is an irregular shape (i.e., not annular), one or more of the inner tube 202 or the outer tube 200 may have a non-circular cross-section, etc., without departing from the scope of the present disclosure.

[0027] The sweep gas and the sample transfer stream flow through the transfer line 104 in substantially opposite directions, and the inner tube 202 initially separates these streams. For example, the inner tube 202 separates an annular region 208, which initially holds the sweep gas, from the interior of the inner tube 202 into which the sample transfer stream flows. The PTFE membrane of the inner tube 202 is substantially permeable to gases (e.g., sweep gas (e.g., Ar), sample transfer gas (e.g., He), purge gas (e.g., N2), etc.), and substantially impermeable to sample particles generated by the laser ablation system 102. Thus, a portion of the sweep gas flows from the annular region 208 through the membrane and into the interior of the inner tube 202 to mix with the sample transfer stream for delivery to the analysis system 106, while a portion of the gas initially present in the sample transfer stream flows from the inner tube 202 through the membrane and into the annular region 208 to be delivered out of the sweep gas outlet 212. For example, Figure 3 An embodiment is shown in which helium gas initially present in the sample transfer stream is transferred from the inner tube 202 through the membrane into the annular region 208, and an argon sweep gas is transferred from the annular region 208 through the membrane and into the inner tube 202 to mix with the sample transfer stream for delivery to the analysis system 106. As shown, substantially all of the helium gas initially present in the sample transfer stream is removed from the sample transfer stream and output from the transfer line 104 via the sweep gas outlet 212. For example, the concentration of the sweep gas in the annular region 208 can drive the exchange of the sample transfer stream gas such that helium gas is exchanged with the argon sweep gas over the length of the transfer line 104. In embodiments, the removal of the initial sample transfer stream gas via the transfer line 104 is in excess of 99%.

[0028] The length of the transfer line 104 may affect the amount or degree of gas exchange between the gases flowing through the inner tube 202 and the annular region 208. In embodiments, a transfer line 104 having a length of about six feet has been experimentally shown to replace substantially all of the initial gas in the sample transfer flow (e.g., 99% or more replacement) with sweep gas. However, the system 100 is not limited to a transfer line 104 of about six feet, wherein the system 100 may also include a transfer line 104 of more than six feet or a transfer line of less than six feet, wherein the length may depend on, for example, the desired amount of gas exchange, the flow rate of the gas flow, the type of gas exchange membrane, or other factors.

[0029] Because the sample transfer flow gas can be replaced with a sweep gas, the system 100 can introduce a sweep gas into the laser ablation system to purge any atmospheric gas present in the ablation cell due to sample transfer without extinguishing the plasma of the ICP torch of the analysis system 106. Furthermore, the system 100 can control the composition of the gas in the sample transfer flow without using physical clamps or constraints on the flow lines in the system 100, such as via a pinch valve, and thus can maintain an open transfer line between the laser ablation system 102 and the analysis system 106.

[0030] Experimental Example - Nitrogen Content in Sample Transfer Stream

[0031] In an embodiment, the system 100 is used to measure the amount of nitrogen removed from a sample transfer stream via a transfer line 104 having a length of about six feet leading to an analysis system 106. In a first portion of the experiment, multiple nitrogen samples were introduced into the ICPMS system at different introduction rates controlled via a mass flow controller (MFC) without an intermediate gas exchange membrane (e.g., downstream of the gas exchange membrane) to quantitatively measure the amount of nitrogen received for different nitrogen flow rates. Example nitrogen flow rates range from about 0.1 mL / min to about 1 mL / min.

[0032] Since nitrogen is introduced into the ICPMS system without an intermediate gas exchange membrane, all nitrogen introduced via the MFC is received by the ICPMS system without being affected by gas exchange via the gas exchange membrane in transfer line 104. The ICPMS system reports the measured nitrogen intensity. A calibration curve of intensity versus flow rate is established based on these measurements, an example of which is shown in Figure 4 Shown in.

[0033] In the next part of the experiment, multiple nitrogen samples were introduced to the ICPMS through the transfer line 104 at different flow rates controlled via the MFC. A gas exchange membrane was present in the transfer line 104 between the introduction site of the nitrogen samples and the ICPMS. Example nitrogen flow rates ranged from about 600 mL / min to about 1500 mL / min. An argon purge gas was introduced into the transfer line 104 to exchange the nitrogen introduced via the MFC with argon before reaching the ICPMS. The ICPMS system reports a measured nitrogen intensity that characterizes the nitrogen that was not removed or otherwise exchanged through the transfer line 104 during transport to the ICPMS system.

[0034] Based on these measurements, a graph of the nitrogen flow rate measured at the ICPMS after transfer through the transfer line 104 and the nitrogen flow rate introduced upstream of the transfer line 104 via the MFC was established, an example of which is shown in Figure 5 Shown in. Figure 4 The calibration curve shown in is used to obtain the y-axis measurement data, wherein the nitrogen intensity measured after the gas exchange in the transfer line 104 is plotted on the calibration curve to determine the nitrogen flow rate remaining after the gas exchange. Figure 5It can be seen that, for a wide range of gas flow rates, the transfer line 104 provides over 99% removal of the nitrogen introduced into the transfer line 104. For example, for a nitrogen flow rate of 800 mL / min (shown as a vertical line on the graph) over a typical laser ablation sample gas flow rate range, the ICPMS system measured a nitrogen flow rate of less than 0.5 mL / min, resulting in greater than 99.93% nitrogen removal.

[0035] in conclusion

[0036] Although the subject matter has been described in language specific to structural features and / or process operations, it will be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A system for controlling gas flow from a laser ablation unit, include: a laser ablation unit configured to generate a sample transfer flow by laser ablation of the sample and introduction of a carrier gas for flowing the ablated sample from the laser ablation unit; an inductively coupled plasma analysis device configured to measure one or more analytes in a sample transfer stream; and A gas exchange membrane transfer line is fluidly coupled between the laser ablation cell and the inductively coupled plasma analysis device, the gas exchange membrane transfer line being configured to replace gas in the sample transfer stream with a sweep gas via gas exchange across a membrane of the gas exchange membrane transfer line.

2. The system according to claim 1, further comprising: include: A mass flow controller is fluidly coupled to a source of the sweep gas and configured to introduce the sweep gas at a controlled flow rate into an inlet of the gas exchange membrane transfer line.

3. The system according to claim 1, in, The gas exchange membrane transfer line includes an inner tube surrounded by an outer tube, wherein at least a portion of the inner tube includes the gas exchange membrane.

4. The system according to claim 3, in, The inner tube defines an inlet configured to receive the purge gas into a region defined between the inner tube and the outer tube.

5. The system according to claim 4, in, The area defined between the inner tube and the outer tube is an annular area.

6. The system according to claim 4, in, The inlet is positioned adjacent an end of the gas exchange membrane transfer line coupled to the inductively coupled plasma analysis device such that the sweep gas and sample transfer stream flow through the gas exchange membrane transfer line at least partially in a counter-flow arrangement.

7. The system of claim 1, further comprising a sample carousel configured to hold a plurality of samples for sequential introduction into the laser ablation unit for generating a separate sample transfer stream from each respective sample.

8. A method for controlling a gas flow from a laser ablation unit, include: transferring a sample transfer stream comprising a plurality of sample particles and at least one gas from the laser ablation system to a gas exchange membrane transfer line; introducing a sweep gas into the gas exchange membrane transfer line; separating at least a portion of the at least one gas from the plurality of sample particles via exchange with at least a portion of the sweep gas; as well as The sample transfer flow is transferred to the inductively coupled plasma analysis device through a gas exchange membrane transfer line.

9. The method according to claim 8, in, Introducing the sweep gas into the gas exchange membrane transfer line includes introducing the sweep gas into the gas exchange membrane transfer line at a controlled flow rate via a mass flow controller.

10. The method according to claim 8, in, The gas exchange membrane transfer line includes an inner tube surrounded by an outer tube, wherein at least a portion of the inner tube includes a membrane permeable to the sweep gas and the at least one gas, the membrane being substantially impermeable to the plurality of sample particles.

11. The method according to claim 10, in, Introducing a sweep gas into the gas exchange membrane transfer line includes introducing the sweep gas into a region between the inner tube and the outer tube, and wherein transferring a sample transfer stream comprising a plurality of sample particles and at least one gas from a laser ablation system to the gas exchange membrane transfer line includes transferring the sample transfer stream through the inner tube.

12. The method according to claim 11, in, The sweep gas and at least a portion of the sample transfer flow travel in opposite directions through the gas exchange membrane transfer line.

13. The method according to claim 8, in, Separating at least a portion of the at least one gas from the plurality of sample particles via exchange with at least a portion of the sweep gas includes separating at least 99% of the at least one gas from the plurality of sample particles via exchange with at least a portion of the sweep gas.

14. A system for controlling gas flow from a laser ablation system, include: a laser ablation system configured to generate a sample transfer flow by laser ablation of the sample and introduction of a carrier gas for flowing the ablated sample from the laser ablation system; an inductively coupled plasma analysis device configured to measure one or more analytes in a sample transfer stream; and A gas exchange membrane transfer line is fluidly coupled between the laser ablation system and the inductively coupled plasma analysis device, the gas exchange membrane transfer line being configured to replace gas in a sample transfer stream with a sweep gas via gas exchange across a membrane of the gas exchange membrane transfer line.

15. The system according to claim 14, further comprising: include: A mass flow controller is fluidly coupled to a source of the sweep gas, the mass flow controller being configured to introduce the sweep gas at a controlled flow rate into an inlet of the gas exchange membrane transfer line.

16. The system according to claim 14, in, The gas exchange membrane transfer line includes an inner tube surrounded by an outer tube, wherein at least a portion of the inner tube includes the gas exchange membrane.

17. The system according to claim 16, in, The inner tube defines an inlet configured to receive the purge gas into a region defined between the inner tube and the outer tube.

18. The system according to claim 17, in, The area defined between the inner and outer tubes is an annular area.

19. The system according to claim 18, in, The inlet is positioned adjacent an end of the gas exchange membrane transfer line coupled to the inductively coupled plasma analysis device such that the sweep gas and sample transfer stream flow through the gas exchange membrane transfer line at least partially in a counter-flow arrangement.

20. The system of claim 14, further comprising a sample carousel configured to hold a plurality of samples for sequential introduction into the laser ablation system for generating a separate sample transfer stream from each respective sample.

Images