Patent Description:
Embodiments herein generally relate to mass spectrometry and, more particularly, to an ion source for a mass spectrometer having an integrated chromatography column.

The coupling of chromatography techniques to mass spectrometry is an analytical technique that combines the resolving power of chromatography with the detection specificity of mass spectrometry. For example, a liquid chromatography-mass spectrometry (LC-MS) system interfaces a liquid chromatography (LC) system with a mass analyzer (i.e., a mass spectrometer (MS) and/or an ion-mobility spectrometer (IMS)). In general, a sample is introduced into the LC portion of the LC-MS system for separation via an LC separation column. The solution of separated compounds output by the LC separation column are provided to an ion source configured to generate ions from the solution for introduction into the mass analyzer. The mass analyzer operates to detect and identify the ions based on their mass-to-charge (m/z) ratio and/or mobility.

The performance of an LC-MS system is reliant on management of the LC system to ensure transfer of the sample solution to the ion source under proper conditions. A primary factor that controls LC system performance is thermal management of the separation column and the separated compound solution as it travels to the mass analyzer. Thermal management of the separated compound solution may be a function of system materials, column heater operation, transport of the solution from the LC separation column to the mass analyzer, and/or the like. Deficient LC system management may result in band broadening, poor peak capacity, and/or reduced detection signal-to-noise (S/N) ratio. In the prior art, <CIT> discloses interfacing chromatographic equipment with a mass spectrometer, while <CIT> discloses an interface probe for chromatography.

In accordance with various aspects of the described embodiments is an ion source assembly that includes a chromatography column in fluid communication with an ion source device. The chromatography column may be arranged immediately adjacent to the ion source.

In accordance with some aspects of the described embodiments is an ion source assembly comprising a chromatography column in fluid communication with an ion source device, the chromatography column arranged within a minimum distance of the ion source, the minimum distance comprising between about <NUM> millimeters (mm) and about <NUM>.

In accordance with some aspects of the described embodiments is an ion source assembly comprising a housing, a chromatography column arranged within the housing, and an ion source device in fluid communication with the chromatography column, at least a portion of the ion source device arranged within the housing, the chromatography column arranged within a minimum distance of the ion source, the minimum distance comprising between about <NUM> and about <NUM>.

In accordance with some aspects of the described embodiments is an ion source assembly comprising a chromatography column in fluid communication with an ion source device, and an interface to couple the chromatography column to the ion source device, the chromatography column arranged within a minimum distance of the ion source, the minimum distance comprising between about <NUM> and about <NUM>.

In accordance with some aspects of the described embodiments is an ion source assembly comprising a chromatography column, an ion source device in fluid communication with the chromatography column, the chromatography column arranged within a minimum distance of the ion source, the minimum distance comprising between about <NUM> and about <NUM>, a column seal loading device having the chromatography column arranged therein and at least a portion of the ion source device arranged therein, and a manifold configured to provide a sample to the chromatography column, the column seal loading device removably coupled to the manifold.

In accordance with some aspects of the described embodiments is an ion source assembly comprising a heater configured to heat a sample received at the ion source assembly, a chromatography column to receive the sample from the heater and to generate a separated compound solution, a housing having the heater and the chromatography column arranged therein, an emitter having an inlet end coupled to the housing, the emitter arranged within a minimum distance of the chromatography column, the minimum distance comprising between about <NUM> and about <NUM>, the emitter configured to receive the separated compound solution from the chromatography column, and generate ions from at least a portion of the separated compound solution.

In accordance with some aspects of the described embodiments is an ion source assembly comprising a housing having a chromatography column, a post-column fluid line, and at least a portion of an ion source device fluidically coupled to the chromatography column arranged therein, the chromatography column fluidically coupled to the emitter via a transfer conduit, the post-column fluid line fluidically coupled to the transfer conduit forming a tee body, the chromatography column arranged within a minimum distance of the ion source, the minimum distance comprising between about <NUM> and about <NUM>. In some embodiments, the post-column fluid line may include a post-column addition (PCA) fluid outlet operative to transfer fluid to the transfer conduit. In various embodiments, the post-column fluid line may include a post-column subtraction (PCS) fluid inlet operative to remove at least a portion of fluid flowing through the transfer conoduit from the chromatography column to the ion source device.

In accordance with some aspects of the described embodiments, an ion source assembly may comprise a chromatography column to generate a separated compound solution by separating a sample, an ion source device fluidically coupled to the chromatography column via a transfer conduit, the transfer conduit having a minimum distance of between about <NUM> and about <NUM>, the ion source device to receive the separated compound solution from the chromatography column and to generate ions from at least a portion of the separated compound solution, a housing having the chromatography column, a post-column addition (PCA) fluid line outlet, and at least a portion of the ion source device arranged therein, the PCA fluid line outlet fluidically coupled to the transfer conduit forming a tee body upstream of the ion source device, the PCA fluid line outlet to provide a fluid for mixing with the separated compound solution.

The minimum distance may be less than <NUM>, although distances of <NUM> or greater are not claimed. In accordance with some aspects of the described embodiments, the minimum distance is less than <NUM>. In accordance with some aspects of the embodiments, the minimum distance is based on a column-ion source device distance. In accordance with some aspects of the described embodiments, the minimum distance may be based on a sample dispersion distance, although this is not claimed. In some embodiments, the minimum distance may be a distance from an outlet of the column to the end of the ion source device (or emitter). In various embodiments, the minimum distance may be a distance from an outlet of the column to the outlet end of the ion source device. In exemplary embodiments, the minimum distance may be a distance from an outlet of the column to the inlet end of the ion source device. In various embodiments, the minimum distance may be from an outlet of the column to a point of ionization.

In accordance with some aspects of the described embodiments, the ion source device may include an electrospray ionization (ESI) emitter. In accordance with some aspects of the described embodiments, the chromatography column may include a liquid chromatography (LC) column. In accordance with some aspects of the described embodiments, the chromatography column may include a high-performance liquid chromatography (HPLC) column. In accordance with some aspects of the described embodiments, the chromatography column may include ultra-high-performance system liquid chromatography (UHPLC) column. In accordance with some aspects of the described embodiments, the chromatography column may have a length of about <NUM> to about <NUM>. In accordance with some aspects of the described embodiments, the chromatography column may have a length of about less than <NUM>. In accordance with some aspects of the described embodiments, the chromatography column may have a length of about <NUM> to about <NUM>. In accordance with some aspects of the described embodiments, the chromatography column may have a length of about <NUM>. In accordance with some aspects of the described embodiments, the chromatography column may have an inner diameter of about <NUM> to about <NUM>. In accordance with some aspects of the described embodiments, the chromatography column may have an inner diameter of about <NUM> to about <NUM>. In accordance with some aspects of the described embodiments, the chromatography column may have an inner diameter of about <NUM> to about <NUM>. In accordance with some aspects of the described embodiments, the chromatography column may have an inner diameter of about <NUM>.

In accordance with some aspects of the described embodiments, an analysis system may include an ion source assembly according to various embodiments and a mass analyzer. In accordance with some aspects of the described embodiments, the analysis system may include a computing device operative to control operational functions of the ion source assembly and/or the mass analyzer. In accordance with some aspects of the described embodiments, the analysis system may include a processing circuitry operative to control operational functions of the ion source assembly and/or the mass analyzer. However, an analysis system is not claimed as such.

Various embodiments may generally be directed toward systems, methods, and/or apparatus for performing mass analysis of a sample. In some embodiments, a system may include a chromatography component, an ion source component, and/or a mass analysis component. The chromatography component may operate to separate a sample using a chromatography column (or separation column) to generate a separated compound solution. In various embodiments, the system may include an ion source assembly having an ion source device (probe or emitter) operative to generate ions from the separated compound solution. The ion source may provide at least a portion of the ions to the mass analyzer for analysis. However, a system comprising a mass analysis component is not claimed as such.

The chromatography column is arranged within the system to minimize the post-column volume of the separated compound solution. In general, the post-column volume is a volume of the separated compound solution between the outlet of the chromatography column and the inlet of the ion source device. For example, in various embodiments, the chromatography column may be arranged within the system to minimize a distance between the chromatography column and the ion source device.

Optimal chromatography, such as liquid chromatography (LC), separation performance requires careful thermal management of the chromatography column. Improper thermal management may result in diminished performance metrics for a mass analysis system, such as band broadening, poor peak capacity, reduced detection S/N (i.e., mass analyzer sensitivity), and/or the like. Conventional liquid chromatography-mass spectrometry (LC-MS) systems require placement of the column within a column heater compartment to provide adequate column thermal management. In addition to column thermal management, reducing the post-column system volume may improve mass analyzer performance metrics. The size of conventional column heaters generally dictates column placement within the LC system and, in particular, prevents placement of the column close to the ion source of the MS. Accordingly, in conventional systems, the distance between the column oven and the ion source requires a lengthy transfer tube to transport column effluent into the MS ion source. This lengthy transfer line reduces chromatographic performance due to its significant post-column fluidic volume.

Accordingly, the post-column volume of the separated compound solution is minimized by minimizing a travel distance of the separated compound solution from an outlet of the chromatography column to the ion source device of an ion source assembly for a mass analyzer. In this manner, mass analyzer systems configured according to some embodiments may provide improved performance, including reduced band broadening, improved peak capacity, improved detection S/N, and/or the like compared to conventional systems.

In this description, numerous specific details, such as component and system configurations, may be set forth in order to provide a more thorough understanding of the described embodiments. It will be appreciated, however, by one skilled in the art, that the described embodiments may be practiced without such specific details. Additionally, some well-known structures, elements, and other features have not been shown in detail, to avoid unnecessarily obscuring the described embodiments.

In the following description, references to "one embodiment," "an embodiment," "example embodiment," "various embodiments," etc., indicate that the embodiment(s) of the technology so described may include particular features, structures, or characteristics, but more than one embodiment may and not every embodiment necessarily does include the particular features, structures, or characteristics. Further, some embodiments may have some, all, or none of the features described for other embodiments.

As used in this description and the claims and unless otherwise specified, the use of the ordinal adjectives "first," "second," "third," etc. to describe an element merely indicate that a particular instance of an element or different instances of like elements are being referred to, and is not intended to imply that the elements so described must be in a particular sequence, either temporally, spatially, in ranking, or in any other manner.

<FIG> illustrates an example of an operating environment <NUM> that may be representative of some embodiments. As shown in <FIG>, operating environment <NUM> may include an analysis system <NUM> operative to perform mass analysis of a sample. In some embodiments, analysis system <NUM> may be or may include a chromatography-mass spectrometry system, such as an LC-MS system. Although LC and LC-MS are used in examples in this detailed description, embodiments are not so limited, as other sample separation and sample analysis systems capable of operating according to some embodiments are contemplated herein.

Analysis system <NUM> may include a sample system <NUM> operative to provide a sample for separation by column <NUM>. In exemplary embodiments, column <NUM> may be an LC column. In some embodiments, column <NUM> may be a column packed with various materials, solutions, and/or the like to separate a sample. Non-limiting examples of materials used to form packed column <NUM> may include porous particles, non-porous particles, superficially-porous particles, silica particles, polymer particles, organohybrid silica particles, combinations thereof, any of the foregoing particles with chemically modified surfaces, and/or the like. In some embodiments, column <NUM> may be part of a high-performance liquid chromatography (HPLC) system or an ultra-performance liquid chromatography (UPLC) system (or ultra-high-performance system liquid chromatography (UHPLC) system). For example, sample system <NUM>, column <NUM>, and/or heater <NUM> may form a chromatography system, such as an LC system, even though portions of the chromatography system may be arranged within or partially within different components (i.e., sample system <NUM>, ion source assembly <NUM>, and/or the like).

In various embodiments, injector <NUM> may inject a sample <NUM> from a sample source <NUM> into column <NUM>. Column <NUM> is arranged within ion source assembly (or ion source probe) <NUM> (see, for example, <FIG> and <FIG>). In some embodiments, at least a portion of column <NUM> may be arranged within ion source assembly <NUM>. In other embodiments, an entirety of column <NUM> may be arranged within ion source assembly <NUM>.

Sample <NUM> may be heated by one or more heaters <NUM>. In some embodiments, at least a portion of column <NUM> may be arranged within heater <NUM>. In other embodiments, column <NUM> may be arranged outside of heater. In various embodiments, heater <NUM> may be arranged in series between injector <NUM> and column <NUM> such that sample <NUM> passes through heater <NUM> before reaching column <NUM>. Although heater <NUM> is depicted in <FIG> as being within ion source assembly <NUM>, embodiments are not so limited. Heater <NUM> may be arranged in ion source assembly, sample system <NUM>, other components of analysis system <NUM>, or combinations thereof. In some embodiments, heater <NUM> may heat a sample (i.e., a mobile phase) prior to entry of the sample into column <NUM>. In exemplary embodiments, various sensors (not shown), such as temperature sensors, may be located within ion source assembly to monitor the temperature of the sample entering column <NUM> and/or the separated compound solution exiting column <NUM>. In some embodiments, ion source assembly130 may include other temperature control devices, including cooling devices (not shown).

A pump <NUM> may operate to pump the sample <NUM> through the column to separate the sample into component parts and generate a separated sample solution <NUM>, for example, based on a retention time of the sample constituents within column <NUM>. Separated sample solution <NUM> may be provided to ion source device (or emitter) <NUM> to generate ions <NUM> from separated sample solution <NUM>. At least a portion of ions <NUM> may be provided to mass analyzer <NUM> for analysis. In various embodiments, ion source assembly <NUM> may be or may include an electrospray ionization (ESI) device or probe. In some embodiments, ion source device <NUM> may operate as an ESI device. Although ESI is used in some examples in this detailed description, embodiments are not so limited as any type of ionization device or technique capable of operating according to some embodiments is contemplated herein. For example, ion source assembly <NUM> may be or may include an atmospheric pressure chemical ionization (APCI) assembly, an atmospheric pressure photo-ionization (APPI) assembly, an impactor spray assembly, and/or the like.

Mass analyzer <NUM> may receive ions <NUM> from ion source assembly <NUM>, for example, from ion source device <NUM>. Mass analyzer <NUM> may be or may include any type of spectrometry device capable of operating according to some embodiments. For example, mass analyzer <NUM> may include a mass spectrometer, an ion mobility spectrometer, a time-of-flight (TOF) mass spectrometer, a quadrupole mass spectrometer, ion trap mass spectrometer, combinations thereof (for example, tandem MS-MS system, and/or the like), variations thereof, and/or the like. In some embodiments, analysis system <NUM> may include, an ESI component, a UHPLC component, and a tandem MS-MS. In various embodiments, analysis system <NUM> may be or may include a MassLynx system or a Xevo system manufactured by Waters Corporation of Milford, Massachusetts, United States of America.

Analysis system <NUM> may include a computing device <NUM> operative to control, monitor, manage, or otherwise process various operational functions of analysis system <NUM>. In some embodiments, computing device <NUM> may be or may include a stand-alone computing device, such as a personal computer (PC), server, tablet computing device. In other embodiments, computing device <NUM> may be or may include processing circuitry in combination with memory, software, and other operational components.

In some embodiments, computing device <NUM>, sample system <NUM>, ion source assembly <NUM>, and/or mass analyzer <NUM> may include processing circuitry (not shown) to perform functions according to some embodiments. Processing circuitry may be any type of analog circuit or digital processor capable of executing programs, such as a microprocessor, digital signal processor, microcontroller, and/or the like. As used in this application, the terms "logic," "circuitry," and/or "module" are intended to refer to a computer-related or analog circuit-related entity, either hardware, a combination of hardware and software, software, or software in execution. For example, processing circuitry of computing device <NUM>, sample system <NUM>, ion source assembly <NUM>, and/or mass analyzer <NUM> may operate to provide sample <NUM> to ion source assembly <NUM> at a particular flow rate, pressure, and/or other operational characteristics. In another example, processing circuitry of computing device <NUM> and/or mass analyzer <NUM> may operate to analyze signals received from a detector of mass analyzer <NUM> produced responsive to detection of ions <NUM> at the detector to generate spectra or other analysis information, for instance, to identify constituents of separated component solution.

<FIG> depicts an ion source assembly according to some embodiments. As shown in <FIG>, ion source assembly <NUM> includes a housing <NUM> having a column <NUM> and an emitter <NUM> at least partially arranged therein. Column <NUM> may include an inlet end <NUM> (a "column inlet end") and an outlet end <NUM> (a "column outlet end"). Column <NUM> may be in fluid communication with emitter <NUM>. For example, column <NUM> may be fluidically coupled to emitter via transfer conduit <NUM>. Emitter <NUM> may include an inlet end <NUM> (an "emitter inlet end") and an outlet end <NUM> (an "emitter outlet end"). Flow through ion source assembly <NUM> may be in a direction starting at column <NUM> and proceeding toward emitter <NUM>. In some embodiments, a heater (not shown (see, for example, <FIG> and <FIG>) may be arranged upstream in fluid communication with column <NUM>. The heater may be operative to heat the sample (i.e., mobile phase) prior to the sample reaching column <NUM>.

A sample fluid may enter column <NUM> at inlet end <NUM>, for example, forced through column <NUM> via a pump and/or injector (not shown). In various embodiments, other fluids may enter column <NUM>, such as solvents, reagents, and/or other compounds (see, for example, <FIG> and <FIG>) alone or in combination with the sample. The sample may be separated into a separated component solution within column <NUM> and may be eluted out of outlet end <NUM> into transfer conduit <NUM>. The separated component solution may flow through transfer conduit <NUM> to emitter <NUM> through inlet end <NUM>. In various embodiments, column <NUM> may be coupled directly to emitter <NUM> without requiring transfer conduit <NUM> (for example, outlet end <NUM> may be directly coupled to inlet end <NUM>). The separated component solution may travel through emitter <NUM> via a capillary <NUM> to a nozzle <NUM> at outlet end. In various embodiments, a voltage may be applied to or adjacent to emitter <NUM> to facilitate the generation of ions. Although a positive voltage is indicated in <FIG>, embodiments are not so limited, as the voltage may be a negative voltage or a positive voltage, depending, for example, on the desired ions, compounds of interest, and/or the like. Ions may be generated from at least a portion of the separated component solution at outlet end <NUM>. For example, in an embodiment in which emitter <NUM> is an ESI device, nozzle <NUM> may include a needle, cone- or funnel-shaped structures, include high voltage connections, nebulization gas, desolvation gas, desolvation heat, and/or the like for providing a jet of charged particles for analysis by a mass analyzer (not shown).

In some embodiments, column <NUM> may be thermally insulated. For example, column <NUM> may include an insulated column and/or may be used with chromatography techniques according to one or more of <CIT>, <CIT>, and <CIT>.

For example, in some embodiments, column <NUM> (an "insulated column" or "vacuum jacketed column") may include an insulating member <NUM> and/or a jacket <NUM>. In various embodiments, insulating member <NUM> may be formed from a vacuum chamber surrounding the column <NUM>. Insulating member <NUM> may include a vacuum chamber having an inert gas arranged therein. In some embodiments, the inert gas may be any of helium, hydrogen, neon, nitrogen, oxygen, carbon dioxide, argon, sulfur hexafluoride, krypton, and xenon. In some embodiments, the vacuum chamber may comprise atmospheric gas. In various embodiments, column <NUM> and insulating member <NUM> may be integrated into a single component forming an insulated chromatography column. Jacket <NUM> may surround column <NUM> and the vacuum chamber may be formed in an area between column <NUM> and jacket <NUM>. In some embodiments, jacket <NUM> may be made of steel. In various embodiments, jacket <NUM> may be an outer layer of a housing of a column heater. The vacuum chamber forming insulating member <NUM> may provide thermal insulation for the column. Insulating member <NUM> may substantially prevent a radial thermal gradient from forming within the column. A heater (for example, heater <NUM> of <FIG>) may heat the sample prior to entry of the sample into column <NUM>.

A vacuum jacketed column according to some embodiments enables placement of column <NUM> outside of a column heater without reducing chromatographic performance. In various embodiments, insulating member <NUM> and/or jacket <NUM> may be integrated to column <NUM> and/or a part of housing <NUM>. In various embodiments, column <NUM> may be a replaceable element which fits inside insulating member <NUM> and/or jacket <NUM>, which may be a part of housing <NUM>. Embodiments are not limited in this context. A vacuum jacketed column is able to be placed within smaller spaces than conventional columns, such as within an ion source.

In various embodiments, column <NUM> (references to column <NUM> may include a vacuum jacketed column) and emitter <NUM> may be engaged with an interface <NUM> within ion source assembly <NUM>. Interface <NUM> may be or may include one or more structures configured to receive column <NUM> and emitter <NUM> and, for example, for support within ion source assembly. Interface <NUM> may include flanges, recess, ridges, cavities, protrusions, clips, and/or the like to affix or otherwise support column <NUM> and/or emitter <NUM> within ion source assembly <NUM>. In some embodiments, interface <NUM> or components thereof may be configured to couple column <NUM> to emitter <NUM> (alone or in combination with the fluidic coupling of column <NUM> and emitter <NUM> via transfer conduit <NUM>).

In some embodiments, the dimensions of column <NUM> may be on an analytical scale. In some embodiments, the dimensions of column <NUM> may be on a microbore scale. In some embodiments, the dimensions of column <NUM> may be on a capillary scale. In some embodiments, the dimensions of column <NUM> may be on a nano scale. In various embodiments, column <NUM> may have a length of about <NUM> millimeters (mm) to about <NUM>. In some embodiments, column <NUM> may have a length of about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, and any value or range between any two of these values (including endpoints). In some embodiments, column <NUM> may have a length of about <NUM>. In some embodiments, column <NUM> may have a length of about <NUM>. In some embodiments, column <NUM> may have a length of about <NUM> to about <NUM>.

In some embodiments, column <NUM> may have an inner diameter of greater than or equal to about <NUM> micrometers (µm). In exemplary embodiments, column <NUM> may have an inner diameter of greater than or equal to about <NUM>. In some embodiments, column <NUM> may have an inner diameter of greater than or equal to about <NUM>. In various embodiments, column <NUM> may have an inner diameter of about <NUM> to about <NUM>. In exemplary embodiments, column <NUM> may have an inner diameter of about <NUM> to about <NUM>. In some embodiments, column <NUM> may have an inner diameter of about <NUM> to about <NUM>. In various embodiments, column <NUM> may have an inner diameter of about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>. <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, and any value or range between any two of these values (including endpoints).

Column <NUM> may be arranged a distance or minimum distance <NUM> from emitter <NUM> ("column-ion source distance" or "column-emitter distance"). In some embodiments, distance <NUM> may be from the side of outlet end <NUM> proximate to (or facing) emitter <NUM> to side of inlet end <NUM> proximate to (or facing) column <NUM>. In some embodiments, the minimum distance may be a distance from an outlet of column <NUM> to the end of emitter <NUM>. In various embodiments, the minimum distance may be from an outlet of column <NUM> to a point of ionization. In some embodiments, distance <NUM> may be minimized (minimum distance) to reduce or even substantially eliminate post-column sample volume compared with conventional systems. In exemplary embodiments, column <NUM> may be arranged immediately adjacent to emitter <NUM>. In various embodiments, distance <NUM> may be about <NUM> (for instance, column <NUM> is directly coupled to emitter <NUM>), about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, and any value or range between any two of these values (including endpoints).

Column <NUM> may be arranged a distance or minimum distance <NUM> ("sample dispersion distance" or "ionization distance") ranging from the outlet of column <NUM> (i.e., outlet end <NUM>) to the sample dispersion or ionization area of emitter <NUM>, which may be or include nozzle <NUM>. In some embodiments, the sample dispersion distance may be a distance between where the sample is eluted by column <NUM> (i.e., out of outlet end <NUM>) and where it is dispersed by emitter <NUM> (i.e., by nozzle <NUM>). In various embodiments, distance <NUM> may be about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, and any value or range between any two of these values (including endpoints).

<FIG> depicts an ion source assembly according to some embodiments. As shown in <FIG>, ion source assembly <NUM> may include a column <NUM> having an inlet end <NUM> and an outlet end <NUM> arranged within a housing <NUM>. In some embodiments, housing <NUM> may be or may include a column seal loading device <NUM>. In various embodiments, column seal loading device <NUM> may be removable from ion source assembly <NUM> to allow for removal and insertion of column <NUM> and/or portions of emitter <NUM>, such as capillary <NUM>. In various embodiments, ion source assembly <NUM> and components thereof may be configured to allow for tool-free replacement of column <NUM>, emitter <NUM>, and/or components thereof. Housing <NUM> may be coupled to or may be a structure of a manifold <NUM> operative to provide sample and other fluids to column <NUM>.

An emitter <NUM> having an inlet end <NUM> and an outlet end <NUM> may be at least partially arranged within housing. For example, inlet end <NUM> may be arranged within housing <NUM>. Column <NUM> and emitter <NUM> may be fluidically coupled via transfer conduit <NUM>. Separated compound solution may exit outlet end <NUM>, travel through transfer conduit <NUM>, and enter emitter <NUM> at inlet end <NUM>. In some embodiments, emitter <NUM> may be an ESI device having a capillary <NUM> operative to deliver the separated compound solution to nozzle <NUM> at outlet end <NUM> to generate ions. In various embodiments, a voltage may be applied to or adjacent to emitter <NUM> to facilitate the generation of ions. In this manner, emitter <NUM>, column <NUM>, and/or portions thereof may be electrically charged. In some embodiments, column <NUM> may be grounded or otherwise electrically isolated from emitter <NUM> to reduce or even prevent column <NUM> from becoming electrically charged. For example, the distance between column <NUM> and emitter <NUM> may be selected to be a length such that the electrical resistance of the mobile phase is sufficient to ground column <NUM> while maintaining spray voltage the emitter <NUM>.

<FIG> depicts an ion source assembly according to some embodiments. As shown in <FIG>, ion source assembly <NUM> may include an MS probe <NUM> having a column <NUM> with an inlet end <NUM> and an outlet end <NUM> arranged within a housing <NUM>. Column <NUM> may be fluidically coupled to an emitter <NUM> having an inlet end <NUM> and an outlet end <NUM> via a transfer conduit <NUM>. In various embodiments, column <NUM> may be electrically isolated from emitter <NUM> and any voltages applied to or otherwise associated therewith. In some embodiments, placement of column <NUM> may allow column <NUM> to be grounded while maintaining ESI spray voltage at emitter <NUM>. For example, in some embodiments, MS probe <NUM> may include an integrated heater <NUM> to heat the sample (for instance, the mobile phase) prior to entry into column <NUM>. In various embodiments, ion source assembly <NUM> and components thereof may be configured to allow for tool-free replacement of column <NUM>, emitter <NUM>, and/or components thereof.

A fluid line <NUM> may be fluidically coupled to column <NUM>, transfer conduit <NUM>, and/or emitter <NUM>. In various embodiments, fluid line <NUM> may be a post-column fluid line arranged upstream from column <NUM> and downstream from emitter <NUM>. In some embodiments, fluid line <NUM> may be fluidically coupled to transfer conduit <NUM>, forming a "T" prior to inlet end <NUM> of emitter <NUM> (see <FIG>). In some embodiments, fluid line <NUM> may operate as a post-column addition (PCA) of fluid prior to the inlet of the ion source for a mass analyzer (for instance, emitter <NUM>). Fluid line <NUM> may be used for infusing a sample, standard, solvent, combinations thereof, and/or other fluids into the flow of fluid entering emitter. Infusing a sample through fluid line <NUM> may allow for, among other things, calibration, tuning, verification or performance, MS method development, flow of ionization-enhancing compounds, solvents to change droplet surface tension, compounds to dilute or otherwise reduce ion suppression, and/or the like. In some embodiments, the post-column tee may allow for direct analysis of a primary dimension effluent in a multidimensional LC system (for example, bypassing the secondary, tertiary, etc., element in a multi-dimensional LC system).

In some embodiments, processing circuitry, for example within computing device <NUM> and/or ion source assembly <NUM>, may be operative to control the fluid type, flow rate, timing, and/or the like of the introduction of fluid via fluid line <NUM>. For example, fluid may be introduced in pulses via fluid line <NUM> and/or the flow rate of fluid flowing through fluid line <NUM> may be adjusted during analysis. Embodiments are not limited in this context.

Although fluid line <NUM> is described as a PCA operative to add fluid in some examples, embodiments are not so limited. For example, fluid line <NUM> may be a post-column subtraction (PCS) fluid line arranged to divert or otherwise remove fluid flowing between column <NUM> and emitter <NUM>. In this manner, for instance, fluid line <NUM> may operate to divert post-column mobile phase away from emitter <NUM>. In some embodiments in which fluid line <NUM> is a PCS, computing device <NUM> and/or ion source assembly <NUM>, may be operative to control the diversion or other removal of fluid via fluid line <NUM>.

<FIG> depicts a detailed view of area <NUM> of <FIG>. As shown in <FIG>, fluid may flow from PCA fluid line <NUM> via PCA conduit <NUM>, which may intersect transfer conduit <NUM> to form tee body <NUM>. Separated compound solution flowing out from column <NUM> via column outlet <NUM> toward emitter <NUM> may be mixed with fluid (for example, solvent) flowing out from PCA fluid line <NUM> via PCA outlet <NUM> to form a PCA solution. The PCA solution may enter emitter <NUM> via emitter inlet <NUM>. In some embodiments, the length of PCA conduit <NUM> may be minimized to facilitate the temperature control, pressure control, concentration, or other management of any PCA solution flowing from fluid line <NUM> to tee body <NUM>.

A UHPLC system was coupled to a tandem quadrupole MS equipped with an electrospray ionization (ESI) ion source. An ESI probe containing a UHPLC separation column was constructed according to some embodiments and compared to a conventional column placed within a column heater compartment. The conventional column was coupled to a commercially-available, unmodified ESI probe. MassLynx <NUM> produced by Waters Corporation of Milford, Massachusetts, United States of America provided instrument control and data collection. The columns were <NUM> x <NUM>, packed with <NUM> superficially-porous C18, and were maintained at <NUM>. The mobile phase was delivered at <NUM>µL/min and a <NUM> minute gradient from <NUM> - <NUM>% acetonitrile in water was executed.

Improvements in performance metrics, including chromatographic peak capacity and column thermal equilibration rates were observed from relocating the column into ion source according to some embodiments. For example, theoretical peak capacity calculations for a <NUM> minute <NUM>-<NUM>% gradient predicted a <NUM>% improvement. When the system was tested over the same gradient, the empirical peak capacity of propranolol, diltazem, verapamil, alprazolam, <NUM>-ethoxycoumarin, and testosterone improved from <NUM> (column-in-column oven) to <NUM> (column arrangement according to some embodiments) when the column placed in the mass spectrometer's prototype ESI probe. A gain of <NUM>% peak capacity was observed.

Column heating and cooling rates we also evaluated between the conventional column oven and a column arranged according to some embodiments. Thermal equilibration was achieved in approximately <NUM> minutes after a commanded change in column set point from <NUM> to <NUM> when the column was placed in a conventional column oven. The same change in temperature required <NUM> minutes to thermally equilibrate with the column arranged according to some embodiments. Conversely, when cooling from a commanded change in column set point from <NUM> to <NUM>, the conventional column required <NUM> to thermally equilibrate while the column arranged according to some embodiments required <NUM> to stabilize. Accordingly, the reduced thermal mass of the column arranged according to some embodiments in comparison to the conventional column oven greatly speeds thermal equilibration time when cooling a column.

The column arranged according to some embodiments facilitates extremely high peak capacity through the reduction of post-column system volume by relocating of the column as close to the ion source as possible. In addition, by reducing the thermal mass of the column environment, column thermal equilibration times can be reduced when employing a column arranged according to some embodiments, thereby facilitating improved efficiency in method development. Further, columns arranged according to some embodiments demonstrate the extremely efficient nature of sub-<NUM> superficially-porous particles and enables high sensitivity and resolution of samples entering the ion source of a LC-MS system.

However, the invention is defined by the appended independent claims.

Claim 1:
An ion source assembly (<NUM>), comprising:
an ion source assembly housing (<NUM>), wherein the ion source assembly housing does not house a mass analyzer;
a chromatography column (<NUM>) arranged within the ion source assembly housing, wherein the chromatography column comprises a liquid chromatography column, a high-performance liquid chromatography (HPLC) column or an ultra-high-performance system liquid chromatography (UHPLC) column;
an ion source device (<NUM>) in fluid communication with the chromatography column, at least a portion of the ion source device arranged within the ion source assembly housing, the ion source device configured to generate ions for a mass analyzer from a separated compound solution exiting the chromatography column, the chromatography column arranged within a distance (<NUM>) to the ion source device of less than about <NUM>; and
a thermally insulating member (<NUM>) housed in the ion source assembly housing for insulating the chromatography column; or
a heater (<NUM>) housed in the ion source assembly housing for heating the chromatography column or a mobile phase entering the chromatography column.