Abstract: Described is a tubing assembly which includes a permanently deformable outer tube, an intermediate tube and an inner tube. A radial seal is provided by a uniform radial crimp having a non-zero longitudinal length at a longitudinal location on the tubing assembly. In some embodiments one or both ends of the assembly have a uniform radial crimp and are polished so that the ends of two or more of the tubes are substantially flush with each other to thereby block the passage of fluids between the ends of the tubes. In other embodiments the uniform radial crimps are at other longitudinal locations where a high pressure seal is desired. The longitudinal length and the depth of each uniform radial crimp can be formed to accommodate the requirements of a particular application so that leakage along the tubing assembly is prevented and void volume is reduced or eliminated.

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: A method may include reducing fluid flow between a rotor and a microfluidic device. The method may further include reducing a sealing force between the rotor and the microfluidic device. The method may also include rotating the rotor relative to the microfluidic device, at the reduced sealing force, to change a fluid pathway therebetween. The method may additionally include reestablishing the sealing force to produce a fluid tight seal between the rotor and the microfluidic device. Moreover, the method may include reestablishing the fluid flow between the rotor and the microfluidic device.

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: A check valve includes a first valve body having a chamber in which second and third valve bodies are located. The check valve also includes a spring-energized seal disposed in the chamber. The spring-energized seal includes a compliant seal body having an annular shape and a resilient member, such as a cantered spring or O-ring, disposed in a pocket of the seal body. The resilient member applies a force to portions of the seal body to prevent the passage of fluid from a valve inlet port to a valve outlet port unless the differential fluid exceeds the cracking pressure of the check valve.

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.

Abstract: Analytical-scale separation column assemblies include a tube with a bore packed with a stationary phase through which a mobile phase flows. In one embodiment, thermal elements are disposed remotely from and unattached to the tube. The thermal elements are in thermal communication with an external surface of the tube for producing a spatial thermal gradient outside of and along a length of the tube. In another embodiment, discrete, spatially separated strips of thermally conductive material are disposed on and wrapped around an external surface of the tube. Thermal elements are disposed remotely from the tube. Each thermal element is in thermal communication with one strip of thermally conductive material by a heat-transfer device. The thermal elements produce a spatial thermal gradient outside of and along a tube length by controlling temperature of each strip of thermally conductive material disposed on and wrapped around the external surface of the tube.

Abstract: A method for detecting an analyte in a chromatography system includes performing a separation using a mobile phase that includes an organic component. The separation is performed with a primary separation module such as a chromatographic column. A first effluent, from the primary separation module, is modulated so that a fluidic plug containing an amount of the organic component and an analyte is provided to a secondary separation module where a secondary separation is performed. A second effluent, from the secondary separation module, includes temporally-resolved organic component and analyte peaks due to selective retention of the analyte. The second effluent is provided to a flame-based detector which is disabled when the organic modifier peak is received and enabled at least during the time when the analyte peak is received. Thus the analyte can be detected without interference from any response of the detector to the organic component peak.

Abstract: The present disclosure relates to an oxidizer, and related methods, for oxidizing polar modifiers in chromatographic mobile phases. The oxidizer enables the use of flame-based detection in chromatographic separations, such as carbon dioxide based chromatography, which employ polar modifiers, such as methanol. Upon exiting a chromatographic column, the mobile phase containing the polar modifier is flowed through an oxidizer that contains a catalyst to oxidize at least a portion of the polar modifier to a species that does not interfere with the function of the flame-based detector. The oxidizer allows for flame-based detection, such as flame ionization detection, in applications in which a polar modifier with a reduced form of carbon is used.

Abstract: 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.

Abstract: A liquid-chromatography module includes a microfluidic cartridge housing a microfluidic substrate with a channel for transporting fluid. The microfluidic substrate has fluidic apertures through which fluid is supplied to the channel. One side of the cartridge has nozzle openings, each aligning with a fluidic aperture in the microfluidic substrate and receiving a fluidic nozzle. A clamping assembly has a plunger that is movable into a clamped position and an end housing that defines a chamber. One wall of the end housing has a fluidic block with fluidic nozzles extending into the chamber. A second wall has a slot through which the cartridge enters the chamber. When moved into the clamped position while the cartridge is in the chamber, the plunger urges the cartridge against the fluidic block such that each fluidic nozzle enters one nozzle opening and establishes fluidic communication with one fluidic aperture in the microfluidic substrate.

Abstract: The present disclosure relates to an oxidizer, and related methods, for oxidizing polar modifiers in chromatographic mobile phases. The oxidizer enables the use of flame-based detection in chromatographic separations, such as carbon dioxide based chromatography, which employ polar modifiers, such as methanol. Upon exiting a chromatographic column, the mobile phase containing the polar modifier is flowed through an oxidizer that contains a catalyst to oxidize at least a portion of the polar modifier to a species that does not interfere with the function of the flame-based detector. The oxidizer allows for flame-based detection, such as flame ionization detection, in applications in which a polar modifier with a reduced form of carbon is used.

Abstract: Methods for transferring a separation procedure from a first chromatographic system to a second one are disclosed that involve substantially matching a pressure profile. In some such methods, a length, an area, and a particle size of a first column in the first system and a flow rate in the first separation procedure are identifiable. Some such methods also involve selecting a combination of a length, an area, and a particle size of a second column in the second system and a flow rate for the second separation procedure. These methods may involve calculating a target length, a target area, or a target particle size for the second column in the second system or a target flow rate for the second separation procedure.

Abstract: The present disclosure relates generally to a system and a method for improving performance of a chromatography system using a highly-compressible fluid based mobile phase (e.g., CO2). In particular, the present disclosure relates to a system that uses a conduit, such as a convergent-divergent nozzle, for reducing pressure noise in a chromatography system using a highly-compressible fluid based mobile phase. The chromatography system can include a conduit, such as a convergent-divergent nozzle, disposed downstream of the column to reduce or prevent the propagation of pressure or density pulses from a back pressure regulator.

Abstract: Described is a chromatographic column assembly that includes an outer tube comprising a metal, a first conduit disposed within the outer tube, a second conduit disposed within the outer tube, and a first joint located between the first conduit and the second conduit. The outer tube is deformed by a first uniform radial crimp at a longitudinal location along the outer tube that surrounds the first conduit on a first side of the first joint, and a second uniform radial cramp at a longitudinal location along the outer tube that surrounds the second conduit on a second side of the first joint. The first and second uniform radial cramps form a fluid-tight seal between the first conduit and the second conduit and each have a substantially flat base region over which a diameter of the outer tube is reduced for a non-zero longitudinal length.

Abstract: Methods for transferring a carbon dioxide based separation procedure from a reference chromatographic system to a target chromatographic system involve alternative techniques for determining system pressure drops not attributable to the column. One technique involves leveraging experimental chromatography to develop a correction factor that is a function of at least one correction coefficient and at least one ratio of the differential analyte retention time to the retention time in the reference system. Another technique involves leveraging other experimental measurements of tubing pressure drops under various condition to develop a lookup table that can be used to identify likely tubing pressure drops in the target system. A third technique leverages knowledge of the separation procedure and the target system and the likely nature of the relevant flow to calculate tubing pressure drops in the target system.