Abstract: A method of performing a chromatographic separation includes modulating a portion of a flowstream to a trap column to retain at least one analyte from the flowstream on the trap column. A flow of a modifier is provided through the trap column to generate an elution comprising the at least one analyte. A flow of a compressible fluid-based chromatography (CFC) mobile phase or CFC solvent is merged with the elution from the trap column to generate a diluted elution. Carbon dioxide may be used as the CFC solvent or as a component of the CFC mobile phase. The diluted elution is provided to a CFC column where at least one analyte is focused at a head of the CFC column. Examples of a flowstream that may be used include an eluent from a chromatography column or a fluid flow from an extraction system.

Abstract: Thermally modulated variable restrictors used in chromatography systems enable independent control of system pressure and linear velocity of a compressible mobile phase passing through a chromatography column. A method for configuring a chromatography system with independent control of system pressure and mass flow rate of a compressible mobile phase includes determining a type of chromatography separation column to be used in the chromatography system, matching a thermally modulated variable restrictor to the type of chromatography separation column for use together during operation of the chromatography system, and bundling the chromatography column with its matching thermally modulated variable restrictor for distribution as a single package.

Abstract: Methods for transferring a carbon dioxide based separation procedure from a first chromatographic system to a second one involve identifying an average column pressure for the separation in the first system is identified, determining a measured average column pressure for the separation in the second system, and comparing the measured average column pressure with the identified average column pressures. To more closely match the identified average column pressure, the methods involve: (a) altering a cross-sectional area of a column packed with media in the second system; and/or (b) adding makeup fluid along the length of the column in the second system. Columns with the characteristics used in the methods and second chromatographic systems are disclosed.

Abstract: Methods for focusing analyte peaks in liquid chromatography using a spatial temperature gradient are provided. Also provided are methods for focusing analyte peaks and improving resolution using a trap column upstream of a separation column. Further, methods are provided in which the trap column placed upstream of the separation column is packed with a temperature-sensitive polymer/copolymer, and a spatial temperature gradient is applied along the trap column for obtaining improved retentivity by trap column stationary phase, and overall improved resolution of analyte peaks.

Abstract: The present disclosure relates to techniques for detecting leaks in a pump. A compressed fluid, such as compressed CO2, is provided through a first channel formed within a pump head. The compressed fluid within the first channel is in contact with at least a portion of a pump piston, and the first channel is substantially sealed using a fluid seal positioned around a portion of the pump piston. A wash fluid is pumped into a second channel formed within a wash seal housing associated with the pump head using a fluid pump. The wash fluid within the second channel surrounds a portion of the pump piston and is separated from the first channel by the fluid seal. A flow rate of fluid exiting the wash seal housing via the second channel is measured, and the existence of a leak is determined based on the measured flow rate.

Abstract: Exemplary embodiments are directed to methods and systems for performing online quantitative supercritical fluid extraction. An extraction cell having a known or characterized volume is loaded with a sample matrix including an analyte of interest. The extraction cell is pressurized with extraction conditions to dissolve the analyte from the sample matrix. The dissolved solution is directed from the extraction cell to a sample loop which also has a characterized volume. The dissolved solution is then directed from the sample loop to a chromatography column and subsequently to a detector. The detector output is compared against a calibration curve to determine an amount of the analyte within the sample matrix based on the known volumes of the sample loop and the extraction cell.

Abstract: The present disclosure relates to methodologies, systems, and devices for extracting CO2 from a mobile phase within a chromatography or extraction system. A mobile phase pump can pump a CO2-based mobile phase through a chromatography column, and a BPR can decompress the mobile phase downstream of the column. Decompressed CO2 can be extracted from the mobile phase using a gas-liquid separator located downstream of the chromatography column. A detector located downstream of the gas-liquid separator can then analyze a substantially liquid mobile phase.

Abstract: The present disclosure relates to optical flow cells for use in chromatography or extraction systems. The optical flow cells include an inlet portion configured to receive a highly compressible fluid and an inlet transition portion or gasket having an internal volume and internal geometry configured to receive the highly compressible fluid from the inlet portion. The optical flow cell also includes an optical path portion configured to receive the highly compressible fluid from the inlet transition portion and direct the highly compressible fluid along an optical flow path. The internal volume and the internal geometry of the inlet transition portion configured to minimize turbulence and eddies within the highly compressible fluid as it travels through the optical flow path.

Abstract: The disclosure relates to a system for liquid sample introduction into a chromatography system. The system includes a syringe, a first valve in fluid communication with the syringe, a second valve in fluid communication with the sample, a vessel located between, and in fluid communication with, the first and second valves, a third valve in fluid communication with the first valve, the second valve and a chromatography column, and a pump in fluid communication with the third valve and a mobile phase. When the valves are in a first position the syringe draws the sample into the vessel. The mobile phase flows to the chromatography column. When the valves are in a second position, a portion of the mobile phase flows into the vessel, mixing with and pressurizing the sample. When the valves are in a third position, the mixed and pressurized sample flows to the chromatography column.

Abstract: The disclosure relates to a system for liquid sample introduction into a chromatography system. The system includes a metering device for drawing up the liquid sample, a first multi-port valve in fluid communication with a first end of the metering device and the liquid sample, a second multi-port valve in fluid communication with a second end of the metering device and a chromatography column, and a pump in fluid communication with the second multi-port valve and a mobile phase. When the valves are in a first position the metering device draws up the liquid sample filling a portion of the metering device. When the valves are in a second position, a remaining portion of the metering device is filled with the mobile phase thereby mixing with and pressurizing the liquid sample. When the valves are in a third position, the mixed and pressurized sample flows to the chromatography column.

Abstract: The present disclosure relates to methodologies, systems, and apparatus for controlling fluid flow within a chromatography system. The chromatography system includes a mobile phase pump configured to pump a liquid mobile phase through a column and a restrictor positioned downstream of the column and upstream of a detector. The system also includes a valve configured to operate in at least two positions. In a first position, the valve is configured to direct the output of the column to bypass the valve and reach the detector, while in the second position the valve directs the output of the column to waste.

Abstract: The present disclosure relates to methodologies, systems, apparatus, and kits for controlling fluid flow within a chromatography system. A makeup pump is configured to pump a makeup fluid into the chromatography system downstream of the column. A first restrictor is located upstream of a detector and downstream of both the makeup pump and the column. Decreasing an output volume of the makeup pump can direct an output from the column through the first restrictor to the detector. Increasing an output volume of the makeup pump can direct the output from the column to a second restrictor located downstream of the makeup pump and the column and in parallel with the first restrictor and the detector.

Abstract: The present disclosure relates to methodologies, systems, apparatus, and kits for introducing a sample within a chromatography system. A makeup pump is configured to pump a makeup fluid through a first restrictor into the chromatography system upstream of the column and downstream of a mobile phase pump. The first restrictor is located upstream of a column and downstream of makeup pump and a sample fluid pump. Decreasing an output volume of the makeup pump can direct a sample fluid from the sample fluid pump through the first restrictor to the column. Increasing an output volume of the makeup pump can direct the sample fluid to a second restrictor located downstream of the makeup pump and in parallel with the column and the detector.

Abstract: Techniques and apparatus for ion source devices with minimized post-column volumes are described. In one embodiment, for example, an ion source assembly may include 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 60 mm and about 150 mm.

Abstract: Exemplary embodiments are directed to a method for diffusing fluid flow within a modular extraction vessel. A modular extraction vessel can be assembled using a plurality of extraction vessel chambers, and each extraction vessel chamber is associated with at least one diffuser element. An extracting solvent is introduced into the modular extraction vessel, and the extracting solvent flows through the extraction vessel chambers. By flowing through the extraction vessel chambers and diffusers, the flow path of the extracting solvent is diffused along an extraction path.

Abstract: A system and method of reducing chromatographic band broadening within a separation column include passing a mobile phase through a length of a separation column, and generating a spatial thermal gradient external to and along the length of the separation column. The spatial thermal gradient is specifically configured to counteract a particular change in a property of the mobile phase as the mobile phase passes through the separation column. For example, the particular change counteracted may be a change in density or in temperature of the mobile phase. For analytical-scale columns, for example, the spatial thermal gradient may be configured to produce temperatures external to and along the length of the separation column that substantially matches temperatures predicted to form in the mobile phase along the column length as the mobile phase passes through the separation column, thereby substantially preventing formation of a radial thermal gradient in the mobile phase.

Abstract: A pressure control device for use with a compressible fluid extraction system is provided, which includes a body portion integrated with a first vessel, and a pressure control element configured to control a first pressure of a second vessel upstream of the first vessel, wherein a decompression event occurs at a point of decompression proximate an outlet of the pressure control element of the pressure control device, wherein an analyte soluble in an extraction solvent stream at the first pressure but has reduced solubility in the extraction solvent stream at the pressure resulting from the decompression event drops out of solution and into the first vessel at the point of decompression Furthermore, an associated extraction system and method is also provided.

Abstract: The present disclosure relates to methodologies, systems and apparatus for controlling pressure in a CO2-based chromatography system. A first CO2 pump operates in constant flow mode and delivers CO2 to a chromatography column, and liquid modifier is introduced to the chromatography column according to a gradient. A second CO2 pump is disposed downstream of the column and operates in constant pressure mode to introduce CO2 into a flow stream at an output of the column. Liquid modifier is also introduced into the flow stream at the output of the column according to a reverse gradient compared to the gradient entering the chromatography column.

Abstract: The present disclosure relates to methodologies, systems and apparatus for controlling pressure in a CO2-based chromatography system. A first pressure control element is located downstream of a CO2-based chromatography system and is disposed to control pressure within the column. A split restrictor is located downstream of the primary pressure control element and is disposed to divert a portion of the mobile phase flow to a detector. A second pressure control element is located downstream of the split restrictor and is disposed to control pressure at the restrictor. While the first pressure control element executes a pressure-controlled gradient separation, the second pressure control element maintains a constant pressure at the restrictor. During a composition-programmed gradient separation, the second control element maintains a constant pressure at the split restrictor while the first pressure control element maintains a constant average density across the column.

Abstract: The present disclosure relates to burner assemblies of flame-based detectors. These burner assemblies are configured to deliver decompressed mobile phase of supercritical fluid chromatography systems to the flame of a flame-based detector while providing for improved optimization of analyte response as well as enhanced flame stability during operation.