Patent Description:
Ion chromatography (IC) is a widely used analytical technique for the determination of anionic and cationic analytes in various sample matrices. Ion exchange-based consumables need to be equilibrated prior to being deployed into operation in an ion chromatography setup. These consumables include eluent generators, continuously regenerated trap columns, analytical and guard columns, suppressors and other consumables that have ion exchange functionalities. The proper equilibration requires special plumbing setup. The consumables need equilibration typically upon first time installation or after the system has been shut down for a long time. <CIT> discloses a multidimensional chromatography apparatus and method.

In a first aspect, a chromatography system includes an electrolytic eluent generator, a first valve, a continuously regenerated trap column, a degasser, a sample injector, a separation column, a suppressor, and a detector. The electrolytic eluent generator is configured to electrolytically produce an eluent. The first valve is configured to switch between an operating position which directs an output of the electrolytic eluent generator to a continuously generated trap column and a waste position which directs the output of the electrolytic eluent generator to waste. The continuously regenerated trap column is configured to remove ionic contaminants from the eluent. The degasser is configured to remove residual gas from the eluent. The sample injector can include a sample injector valve assembly. The sample injector valve assembly is configured to switch between an operation mode which directs an output of the degasser to a separation column, a load mode which loads a sample onto the separation column, and a regenerant mode which directs the output of the degasser to a regenerant line. The separation column is configured to chromatographically separate components of a sample. The suppressor is configured to reduce the eluent conductivity. The detector is configured to detect the presence of components of the sample.

In various embodiments of the first aspect, the sample injector valve assembly can include a three position valve to switch between an operation position corresponding to the operation mode, a load position corresponding to the load mode, and a regenerant position corresponding to the regenerant mode.

In various embodiments of the first aspect, the sample injector valve assembly can include a second valve to switch between a first operate position which directs an output of the degasser to a third valve and a load position which directs the sample onto the separation column; and a third valve to switch between a second operate position which directs an output of the second valve to the separation column and a regenerant position which directs the output of the second valve to a regenerant line.

In various embodiments of the first aspect, the chromatography system can further include a check valve on the regenerant line.

In various embodiments of the first aspect, the chromatography system can further include a flow restrictor between the first valve and waste.

In various embodiments of the first aspect, the chromatography system can further include a controller, wherein the controller can be configured to switch the first valve to the waste position during an electrolytic eluent generator equilibration time period. In particular embodiments, the controller can be further configured to switch the second valve to the regenerant position during a continuously regenerated trap column equilibration time period.

In various embodiments of the first aspect, the chromatography system can further include a third valve configured to switch between an operating position which directs the output of the separation column to the suppressor and a waste position which directs the output of the separation column to waste. In particular embodiments, the chromatography system can further include a controller, wherein the controller can be configured to switch the third valve to the waste position during a separation column equilibration time period.

In various embodiments of the first aspect, the suppressor can be a chemical suppressor.

In various embodiments of the first aspect, the suppressor can be an electrolytic suppressor. In particular embodiments, the chromatography system can further include a fourth valve configured to switch between an operating position which directs the output of the detector to a regenerant line and a waste position which directs the output of the detector to waste. In particular embodiments, the chromatography system can further include a controller, wherein the controller can be configured to switch the fourth valve to the waste position during a suppressor equilibration time period.

In a second aspect, a method includes switching a first valve to a waste position which directs the output of an electrolytic eluent generator to waste; flowing liquid through the electrolytic eluent generator for an electrolytic eluent generator equilibration time period; switching the first valve to an operating position which directs the output of an electrolytic eluent generator to a continuously regenerated trap column; switching a second valve downstream of the continuously regenerated trap column to a regenerant position which directs a downstream flow from the continuously regenerated trap column to a regenerant line; flowing liquid through the continuously regenerated trap column for a continuously regenerated trap column equilibration time period; switching the second valve to an operation position which directs the downstream flow to a separation column; and validating the operation of the chromatography system.

In various embodiments of the second aspect, the method can further include switching a third valve to a waste position which directs the output of the separation column to waste; flowing liquid through the separation column for a separation column equilibration time period; and switching the third valve to an operating position which directs the output of the separation column to a suppressor.

In various embodiments of the second aspect, the suppressor can be a chemical suppressor.

In various embodiments of the second aspect, the suppressor can be an electrolytic suppressor. In particular embodiments, the method can further include switching a fourth valve to a waste position which directs the output of a detector to waste; flowing liquid through a suppressor to the detector for a suppressor equilibration time period; and switching the fourth valve to an operating position which directs the output of the detector to a regenerant line. In particular embodiments, the method can further include providing an alternate regenerant flow to the suppressor during the suppressor equilibration time period.

In a third aspect, a method can include switching a valve to an equilibrate position which directs the output of an electrolytic consumable device to waste or a regenerant line; flowing liquid through the electrolytic consumable device for an electrolytic consumable device equilibration time period; switching the first valve to an operating position; and validating the operation of the chromatography system.

In various embodiments of the third aspect, the electrolytic consumable device can include an electrolytic eluent generator.

In various embodiments of the third aspect, the electrolytic consumable device can include a continuously regenerated trap column.

In various embodiments of the third aspect, the electrolytic consumable device can include a separation column.

In various embodiments of the third aspect, the electrolytic consumable device can include an electrolytic suppressor.

Embodiments of systems and methods for ion separation are described herein.

In this detailed description of the various embodiments, for purposes of explanation, numerous specific details are set forth to provide a thorough understanding of the embodiments disclosed. One skilled in the art will appreciate, however, that these various embodiments may be practiced with or without these specific details. In other instances, structures and devices are shown in block diagram form. Furthermore, one skilled in the art can readily appreciate that the specific sequences in which methods are presented and performed are illustrative and it is contemplated that the sequences can be varied.

Unless described otherwise, all technical and scientific terms used herein have a meaning as is commonly understood by one of ordinary skill in the art to which the various embodiments described herein belongs.

The proper equilibration of ion exchange-based consumables, such as eluent generators, continuously regenerated trap columns, analytical and guard columns, and suppressors, requires a special plumbing setup and is generally implemented manual implemented manually and as a separate setup prior to analysis. The consumables typically need equilibration upon first time installation and after the system has been shut down for a long time.

The systems and methods disclosed herein solve multiple issues related to the equilibration of ion exchange-based consumables. Upon first time install, the system can take several days to install and achieve acceptable performance due to the various equilibration routines that need to be performed as prescribed for the consumables. Subsequent replacement of consumables by a user would require hands on time to ensure that the consumables are equilibrated per the written procedures. Additionally, system performance can be compromised after the system is restarted after an extended shut down. To achieve good performance some level of equilibration is needed and adds to the hands-on time. Further, the pressure contribution of the various consumables may not be readily apparent and needs additional steps from the users for diagnosis.

<FIG> illustrates a chromatography system <NUM> Chromatography system <NUM> includes a pump <NUM>, an electrolytic eluent generator <NUM>, a continuously regenerated trap column <NUM>, a degasser <NUM>, a sample injector <NUM>, a chromatographic separation device <NUM>, an electrolytic suppressor <NUM>, a detector <NUM>, and a microprocessor <NUM>. Chromatographic separation device <NUM> may be in the form of a capillary column or an analytical column. Line <NUM> may be used to transfer the liquid from an output of detector <NUM> to the regenerant channel inlet of the electrolytic suppressor <NUM>. Line <NUM> may be used to transfer liquid from an outlet of the regenerant channel of the electrolytic suppressor <NUM> to an inlet of the regenerant channel of the continuously regenerated trap column <NUM>. Recycle line <NUM> can be optionally used to transfer liquid from an outlet of the continuously regenerated trap column <NUM> to an inlet of the degasser <NUM> or can be directed to waste. Liquid from the outlet of the degasser <NUM> when configured with the flow from the regenerant flow from the continuously regenerated trap column can be directed to waste <NUM>.

Pump <NUM> can be configured to pump a liquid from a liquid source <NUM>, such as deionized water, and be fluidically connected to electrolytic eluent generator <NUM>. Pump <NUM> can be configured to transport the liquid at a pressure ranging from about <NUM> PSI to about <NUM>,<NUM> PSI. Under certain circumstances, pressures greater than <NUM>,<NUM> PSI may also be implemented. It should be noted that the pressures denoted herein are listed relative to an ambient pressure (<NUM> PSI to <NUM> PSI). Pump <NUM> may be in the form of a high-pressure liquid chromatography (HPLC) pump. In addition, pump <NUM> can also be configured so that the liquid only touches an inert portion of pump <NUM> so that a significant amount of impurities does not leach out. In this context, significant means an amount of impurities that would interfere with the intended measurement. For example, the inert portion can be made of polyether ether ketone (PEEK) or at least coated with a PEEK lining, which does not leach out a significant amount of ions when exposed to a liquid.

An eluent is a liquid that contains an acid, base, salt, or mixture thereof and can be used to elute an analyte through a chromatography column. In addition, an eluent can include a mixture of a liquid and a water miscible organic solvent, where the liquid may include an acid, base, salt, or combination thereof. Electrolytic eluent generator <NUM> is configured to generate a generant. A generant refers to a particular species of acid, base, or salt that can be added to the eluent. In an embodiment, the generant may be a base such as cation hydroxide or the generant may be an acid such as carbonic acid, phosphoric acid, acetic acid, methanesulfonic acid, or a combination thereof.

Referring to <FIG>, eluent generator <NUM> can be configured to receive the liquid from pump <NUM> and then add a generant to the liquid. The liquid containing the generant can be outputted from eluent generator <NUM> to an inlet of continuously regenerated trap column <NUM>.

Continuously regenerated trap column <NUM> is configured to remove cationic or anionic contaminants from the eluent. Continuously regenerated trap column <NUM> can include an ion exchange bed with an electrode at the eluent outlet. An ion exchange membrane stack can separate the eluent from a second electrode and contaminate ions can be swept through the ion exchange membrane stack towards the second electrode. The ion exchange membrane stack can include one or more ion exchange membranes. In various embodiments, anion removal can utilize an anion exchange bed with a cathode at the eluent outlet separated from an anode by an anion exchange membrane. Alternatively, cation removal can utilize a cation exchange bed with an anode at the eluent outlet separated from a cathode by a cation exchange membrane.

Degasser <NUM> is used to remove residual gas. In an embodiment, a residual gas may be hydrogen and oxygen. Degasser <NUM> may include a tubing section that is gas permeable and liquid impermeable such as, for example, amorphous fluoropolymers or more specifically Teflon AF. The flowing liquid can be outputted from degasser <NUM> to sample injector <NUM> with a substantial portion of the gas removed.

Sample Injector <NUM> is used to inject a bolus of a liquid sample into an eluent stream. The liquid sample may include a plurality of chemical constituents (i.e., matrix components) and one or more analytes of interest. The sample injector <NUM> can include an auto sampler <NUM>, sample loop <NUM>, and a multiport valve <NUM>. The auto sampler <NUM> can draw a sample from a sample container. The multiport valve <NUM> can be in a first position to allow the sample to fill the sample loop <NUM> to the desired volume. After the sample loop <NUM> is filled, the multiport valve can switch to a second position and the eluent stream can drive the sample onto the chromatographic separation device <NUM>.

Chromatographic separation device <NUM> is used to separate various matrix components present in the liquid sample from the analyte(s) of interest. Typically, chromatographic separation device <NUM> may be in the form of a hollow cylinder that contains a packed stationary phase. As the liquid sample flows through chromatographic separation device <NUM>, the matrix components and target analytes can have a range of retention times for eluting off of chromatographic separation device <NUM>. Depending on the characteristics of the target analytes and matrix components, they can have different affinities to the stationary phase in chromatographic separation device <NUM>. An output of chromatographic separation device <NUM> can be fluidically connected to electrolytic suppressor <NUM>.

Electrolytic suppressor <NUM> is used to reduce eluent conductivity background and enhance analyte response through efficient exchange of eluent counterions for regenerant ions. Electrolytic suppressor <NUM> can include an anode chamber, a cathode chamber, and an eluent suppression bed chamber separated by ion exchange membranes. The anode chamber and/or cathode chamber can produce regenerate ions or transport supplied regenerant ions. The eluent suppression bed chamber can include a flow path for the eluent separated from the regenerant by an ion exchange barrier and eluent counterions can be exchanged with regenerate ions across the ion exchange barrier. An output of electrolytic suppressor <NUM> can be fluidically connected to detector <NUM> to measure the presence of the separated chemical constituents of the liquid sample.

Detector <NUM> may be in the form of ultraviolet-visible spectrometer, a fluorescence spectrometer, an electrochemical detector, a conductometric detector, mass spectrometry detector or a combination thereof.

An electronic circuit may include microprocessor <NUM>, a timer, and a memory portion. In addition, the electronic circuit may include a power supply that are configured to apply a controlling signal, respectively. Microprocessor <NUM> can be used to control the operation of chromatography system <NUM>. Microprocessor <NUM> may either be integrated into chromatography system <NUM> or be part of a personal computer that communicates with chromatography system <NUM>. Microprocessor <NUM> may be configured to communicate with and control one or more components of chromatography system such as pump <NUM>, pump <NUM>, eluent generator <NUM>, sample injector <NUM>, and detector <NUM>. The memory portion may be used to store instructions to set the magnitude and timing of the current waveform with respect to the switching of sample injector <NUM> that injects the sample.

Ion exchange materials upon first time install or long-term storage can bleed leachates that can be oligomeric or ionic in nature. Since these compounds can be retained in downstream ion exchange components they can cause delay in system startup time and in some instances can overwhelm the capacity of the downstream components causing performance issues such as lower the sensitivity, retain peaks of interest causing poor peak shapes, increase background and the noise. The solution to the above issue is to equilibrate the consumables by following prescribed protocols and usually these are done to the consumables on an individual basis and then replumbed into the system prior to usage. These are additional steps the users have to perform and adds to hands on time. Every time a consumable has to be replaced on the IC system, the replacement consumable needs to be equilibrated prior to use and this aspect also adds to significant down time and labor. Not pursuing the required equilibration steps can contaminate downstream consumables with leachates and can lead to significant performance issues and additional down time. Errors in following the prescribed steps can also add to the system down time. Issues with system startup after a delayed shutdown period can also be a common problem encountered in the field.

Additionally, it can be desirable to measure the pressure contribution of the consumables to the overall system pressure as an indicator of some issue with that consumable and compromised performance. With electrolytic devices that have separate regenerant pathways that contain electrodes, this pathway also needs to be replumbed and flushed with reagents or water containing streams in order to prepare the consumable to be deployed on the system for standard operation. Facilitating the regeneration aspect is another challenge from a plumbing configuration perspective and presently requires hands on time by the user. These issues can be addressed with a valving scheme that allows easy deployment of the equilibration method and the system can resume normal operation after the execution of the required steps to insure excellent performance of the IC system. While the discussed embodiments show specific valve configurations it is apparent from this disclosure that other valve configurations can be used that are available in the industry.

Referring to <FIG>, a consumable <NUM> that requires to be equilibrated is upstream from a valve <NUM>. In a first position <NUM>, valve <NUM> directs the flow from the consumable to an equilibration setup and then route this to waste or as a water stream for regenerating a regenerant pathway for electrolytic devices. The second position <NUM> on the valve resumes normal plumbing or operation of the IC system. Thus, a valving scheme could enable an automated deployment of the ion chromatograph. The equilibration steps can be tailored to the consumable and require a specific setup for each individual consumable. Optional reagents <NUM> could be routed for electrolytic consumables to regenerate the regenerant pathway. The systems and methods disclosed herein can achieve these functions in an automated fashion with a method deployment from the chromatographic software that controls the system operation. Thus, hands on time and labor associated with these setups are significantly reduced or eliminated. By providing a valving setup that facilities equilibration of upstream consumables, overall equilibration time can be reduced allowing for the system to startup with minimal down time.

<FIG> shows an exemplary ion chromatography system <NUM>. A six port two position valve <NUM> is installed between the eluent generator <NUM> and the continuously regenerated trap column <NUM> as shown. In a first position (not shown), the valve <NUM> routes the output of the eluent generator <NUM> to the continuously regenerated trap column <NUM>. In a second position, the valve <NUM> routes the output of the eluent generator <NUM> to a flow restrictor <NUM>, such as a flow restrictor rated at <NUM> psi or other user selected value, and then diverts this to waste. The prescribed equilibration for the eluent generator <NUM> can be pursued and routed to waste and then the valve <NUM> can be switched to resume normal operation. In various embodiments, the waste from valve <NUM> can be routed to an optional detector <NUM>. In this way equilibration of eluent generator <NUM> can be monitored to ensure sufficient equilibration of the eluent generator <NUM>. Other waste streams can similarly be directed to optional detectors, such as detector <NUM> or separate detectors to monitor the waste stream and ensure satisfactory equilibration of each component.

Next the output stream from the continuously regenerated trap column <NUM> can be routed to the degasser <NUM> and then to the sample injector <NUM>. The injection valve <NUM> can be a <NUM> port <NUM> position valve in place of the standard <NUM> port <NUM> position valve. The additional 7th port is connected to the pump flow in the 3rd position of the valve and could be leveraged during equilibration of the consumables. The 7th port can be connected to waste on the regenerant line <NUM>. To ensure that the flow is routed in the correct direction a check valve <NUM> is deployed on the regenerant line between the electrolytic suppressor <NUM> out port and the continuously regenerated trap column <NUM> regenerant in port. Thus, this configuration could be used to regenerate the continuously regenerated trap column <NUM> with a regenerant flow established to provide water for the electrolysis reactions.

The injection valve in the 1st position can load the sample while the eluent is routed directly to the column. The injection valve in the 2nd position can inject the sample similar to the standard setup and the eluent is routed via the sample loop to the column for analysis. In the 3rd position the eluent that is pumped through the continuously regenerated trap column <NUM> is routed to the regenerant side of the continuously regenerated trap column <NUM> and to waste. This configuration would help the equilibration of the continuously regenerated trap column <NUM> before resuming normal operation in the 1st or 2nd position.

Next the eluent is routed to the chromatographic separation device <NUM> and then routed to a valve <NUM> which, in this embodiment, is shown as a three-port valve with two positions. In position one, the valve routes the eluent from the chromatographic separation device <NUM> to the electrolytic suppressor <NUM> eluent in port. In a second position, the eluent from the chromatographic separation device <NUM> is routed to waste. The second position is used to equilibrate the chromatographic separation device <NUM> prior to standard operation. The advantage of this setup is that any leachates from the chromatographic separation device <NUM> are flushed to waste rather than into the downstream consumables.

The suppressed eluent from the electrolytic suppressor <NUM> eluent out port is routed to a detector <NUM> and then routed to a three-port dual position valve <NUM>. In a first position, the suppressed eluent is routed to the regenerant channel of the electrolytic suppressor <NUM> to provide water required for the electrolysis reactions. In a second position, the suppressed eluent from the eluent out port of the electrolytic suppressor <NUM> is routed through the detector <NUM> and is routed to waste. Upon installation, the electrolytic suppressor <NUM> can be equilibrated in this setup. An optional regenerant stream (not shown) can be deployed to flush the suppressor regenerant channels.

Another benefit of the embodiment of <FIG> is that when each consumable is routed to waste the downstream pressure can be easily obtained by subtracting from the total system pressure. Thus, the embodiment of <FIG> provides the consumable pressure contribution and could be used for troubleshooting purposes when the system pressure escalates due to a consumable issue. This can provide valuable diagnostic information. Also, a quick rinse of the consumable and routing it to waste can ensure good system performance.

<FIG> shows a simplified setup where only two valves (valves <NUM> and <NUM>) are deployed to allow for equilibration of the eluent generator <NUM> and the continuously regenerated trap column <NUM> as discussed previously. This setup may be useful when a) the columns do not leach out significantly to alter performance b) when the suppressor used is a chemical suppressor which would not require the setup of <FIG>. Also, in cases where the user can pursue the equilibration of the column and the suppressor in a manual mode.

<FIG> shows a method <NUM> of preparing a chromatography system for use. At <NUM>, equilibration of the system is initiated. In various embodiments, a user interface can provide the user an option for equilibration of the system. A human user can initiate equilibration of the system through the user interface, such as by pressing a button. The equilibration can also be pursued in an automated fashion by programming the equilibration prior to starting the system and then resuming normal operation in a fully automated fashion.

Referring to <FIG>, at <NUM>, the system switches a valve located after an electrolytic eluent generator, such as valve <NUM> of <FIG>, to a equilibrate position. The equilibrate position directs the flow out of the electrolytic eluent generator to waste. At <NUM>, the electrolytic eluent generator is equilibrated. In various embodiments, a pump can supply deionized water to the eluent generator for an equilibration time according to established protocols. In various embodiments, the established protocols can be provided by the manufacturer of the chromatography system or the eluent generator, or the protocols can be provided by the user.

At <NUM>, the system switches the valve located after the eluent generator to a normal operating position and switches a valve located after the continuously regenerated trap column, such as valve <NUM> of <FIG>, to an equilibration position. The equilibration position directs the flow downstream of the continuously regenerated trap column to a regenerate line, such as line <NUM> of <FIG>, to provide a regenerant flow to the continuously regenerated trap column. At <NUM>, the continuously regenerated trap column is equilibrated. In various embodiments, a pump can supply deionized water to the eluent generator which can supply eluent to the continuously regenerated trap column for an equilibration time according to established protocols. At <NUM>, the system switches the valve located after the continuously regenerated trap column to a normal operating position.

In various embodiments, it may be desirable to equilibrate the separation column and/or the suppressor. In other embodiments, it may not be necessary to equilibrate the separation column and suppressor, such as if the separation column does not leach out significantly and/or when the suppressor is a chemical suppressor rather than an electrolytic suppressor. Optionally, at <NUM>, the system can switch a valve located after the separation column, such as valve <NUM> of <FIG>, to an equilibration position. In various embodiments, the equilibration position can direct the flow downstream of the separation column to waste. Optionally, at <NUM>, the separation column can be equilibrated. In various embodiments, a pump can supply deionized water to the eluent generator which can produce an eluent flow to the separation column for an equilibration time according to established protocols.

Optionally, at <NUM>, the system can switch the valve located after the separation column to a normal operating position and switch a valve located after the electrolytic suppressor, such as valve <NUM> of <FIG>, to an equilibration position. In various embodiments, the equilibrate position can direct the flow out of the electrolytic suppressor to waste. Optionally, at <NUM>, the electrolytic eluent generator can be equilibrated. In various embodiments, a pump can drive an eluent flow through the column and to the suppressor for an equilibration time according to established protocols. Optionally, at <NUM>, the system can switch the valve located after the electrolytic suppressor to a normal operating position.

At <NUM>, the system can prompt a human user or a robot to load validation samples and the human user can load the validation samples. In various embodiments, the sample can be loaded after equilibration of the electrolytic consumables. In other embodiments, the system may prompt the user and the user may load the samples at <NUM> when the equilibration is initiated which would eliminate the need for the human user to return to the chromatographic system between equilibration and validation. At <NUM>, the system can perform a validation routine to ensure the system is operating within requirements.

In various embodiments, the system can measure the pressure after equilibration of each component to determine the pressure contribution of
<FIG> shows a method <NUM> of preparing a chromatography system for use after replacement of an electrolytic consumable device. The electrolytic consumable device may be an electrolytic eluent generator, a continuously regenerated trap column, a separation column, an electrolytic suppressor, or the like. At <NUM>, a human user can replace the electrolytic consumable device and initiate equilibration of the electrolytic consumable device. In various embodiments, the system can provide a user interface for initiating equilibration of the device and the human user can initiate equilibration, such as by selecting the device and pressing a button to initiate equilibration.

At <NUM>, the system can switch a valve located downstream of the electrolytic consumable to an equilibrate position. In various embodiments, the equilibrate position can direct the flow out of the electrolytic consumable device to waste or to a regenerant line. At <NUM>, the electrolytic consumable device can be equilibrated. In various embodiments, the system can cause a pump to drive a flow through the electrolytic consumable device for an equilibration time according to established protocols. In various embodiments, the established protocols can be provided by the manufacturer of the chromatography system or the eluent generator, or the protocols can be provided by the user. At <NUM>, the system can switch the valve located downstream of the electrolytic consumable to a normal operating position.

Claim 1:
A chromatography system (<NUM>, <NUM>, <NUM>) comprising:
an electrolytic eluent generator (<NUM>) configured to electrolytically produce an eluent;
a first valve (<NUM>, <NUM>) configured to switch between an operating position (<NUM>) which directs an output of the electrolytic eluent generator (<NUM>) to a continuously generated trap column (<NUM>) and a waste position (<NUM>) which directs the output of the electrolytic eluent generator (<NUM>) to waste;
the continuously regenerated trap column (<NUM>) configured to remove ionic contaminants from the eluent;
a degasser (<NUM>) configured to remove residual gas from the eluent;
a sample injector (<NUM>, <NUM>) including a sample injector valve assembly configured to switch between an operation mode which directs an output of the degasser (<NUM>) to a separation column (<NUM>), a load mode which loads a sample onto the separation column (<NUM>), and a regenerant mode which directs the output of the degasser (<NUM>) to a regenerant line (<NUM>, <NUM>);
the separation column (<NUM>) configured to chromatographically separate components of a sample;
a suppressor (<NUM>) configured to reduce the eluent conductivity; and
a detector (<NUM>) configured to detect the presence of components of the sample.