A liquid chromatography system and method utilizes a mobile phase comprising liquified compressible gas and miscible organic solvents. The compressible fluid may be carbon dioxide (CO2). Liquid CO2 tapped from an existing source is depressurized through a flow control metering station before adding solvent. The mobile phase flows through a sample vessel containing analytes and chromatography column for sample separation. A back pressure regulator maintains a set elution pressure in the chromatography column. CO2 advantageously remains in liquid phase for elution in the column, thereby avoiding two-phase conditions adversely affecting analyte resolution. An equilibration bypass flow loop may be provided to separate normal sample elution from initial CO2 flow equilibration, thereby allowing rapid exchange of samples with minimal downtime. System CO2 pressures less than 100 bar and room temperature may be used during the process, thereby obviating the need for high pressure pumps and chillers of supercritical fluid chromatography.

To provide a means capable of simultaneously and accurately analyzing a component derived from a carrier for liquid phase peptide synthesis with, for example, a target peptide.

A method for simultaneously analyzing a carrier for liquid phase peptide synthesis, a component derived from the carrier for liquid phase peptide synthesis, an amino acid to which the carrier for liquid phase peptide synthesis is bound, and a peptide compound to which the carrier for liquid phase peptide synthesis is bound, with a target peptide or final target peptide, the analysis method using high-performance liquid chromatography or supercritical fluid chromatography using an alcohol as an eluent.

A degassing device 2 includes: a built-in absorbance measurement section 28 using an LED light source and measuring the intensity of light transmitted through a mobile phase passing through a flow cell; and a solenoid valve 26 switchable between two states with and without the mobile phase passed through a degassing tube 21. The passage-switching operation by the solenoid valve is performed so as to obtain detection signals of the transmitted light in the absorbance measurement section when the mobile phase drawn from a mobile phase container by a liquid-feeding pump 40 is passed through the degassing tube for degassing as well as when the mobile phase is not passed through the degassing tube for degassing. A signal processor 29 calculates the difference in absorbance based on those detection signals, estimates the degree of degassing based on that difference, and displays the result on a display unit 32.

A degassing device 2 includes: a built-in absorbance measurement section 28 using an LED light source and measuring the intensity of light transmitted through a mobile phase passing through a flow cell; and a solenoid valve 26 switchable between two states with and without the mobile phase passed through a degassing tube 21. The passage-switching operation by the solenoid valve is performed so as to obtain detection signals of the transmitted light in the absorbance measurement section when the mobile phase drawn from a mobile phase container by a liquid-feeding pump 40 is passed through the degassing tube for degassing as well as when the mobile phase is not passed through the degassing tube for degassing. A signal processor 29 calculates the difference in absorbance based on those detection signals, estimates the degree of degassing based on that difference, and displays the result on a display unit 32.

Methods for separating, monitoring, identifying, and/or quantifying a plurality of ionic species in a mixture are disclosed herein. The ionic species can include a plurality of amines in an industrial fluid. The methods can include a first chromatography step, a second chromatography step, and optionally, a third chromatography step. The first chromatography step and second chromatography step can be performed simultaneously, for example in a dual channel apparatus, such that the method can be performed in less than about 24 hours. Disclosed herein are also methods for efficiently operating a refinery.

A method and a system for introducing a sample into a mobile phase of a chromatography system is provided. The method includes initially directing the mobile phase directly into a separation unit of the chromatography system, bypassing a sample loop, the mobile phase including a combined solvent, metered from a pressurized first solvent and a second solvent; loading the sample into the sample loop, while the mobile phase continues to be directed directly into the separation unit; pressurizing the sample in the sample loop with the pressurized first solvent, while the mobile phase continues to be directed directly into the separation unit; and switching the sample loop into the mobile phase, thereby introducing the pressurized sample to the separation unit.

A high performance liquid chromatography method for analysis of a MN diagnostic and therapeutic ligand and precursors is revealed. Polarity of eluents used during elution is changed to remove impurities. First use a first eluent with a lower ratio of acetonitrile as a mobile phase to elute analytes. Then a second eluent in which a ratio of acetonitrile is increased into 9799% is used to elute the analytes for at least 20 minutes. Next use the first eluent to elute the analytes for at least 60 minutes. Thus no residual impurities are left in the column and the analytes remain in the column stably. Therefore a more accurate and reproductive result is obtained.

An apparatus introduces a sample into a separation unit of a chromatography system with a mobile phase, including first and second mobile phase components. The apparatus includes first and second pump systems, and an injection unit. The first pump system provides the first mobile phase component, first and second portions of the first mobile phase component flowing through first and second branches, respectively. The second pump system provides the second mobile phase component, a first portion of the second mobile phase component flowing through a third branch. The injection unit receives a combined stream of the first portions of the first and second mobile phase components provided via the first and third branches, respectively, and injects the sample into the combined stream to form a sample-containing stream, which is subsequently combined with the second portion of the first mobile phase component to form a diluted sample-containing stream.

The present disclosure provides a method for measuring a concentration of a per- and polyfluoroalkyl substance and a liquid chromatography-tandem mass spectrometry system. The method includes: measuring concentrations of a plurality of per-and polyfluoroalkyl substances in a sample by liquid chromatography-tandem mass spectrometry in a primary measurement process of eluting the sample with an alkaline mobile phase, in which the plurality of per- and polyfluoroalkyl substances at least include one or more perfluoroalkyl phosphonic acids/phosphinic acids or polyfluoroalkyl phosphate esters. According to the method, by using the alkaline mobile phase to elute the sample, the rapid analysis on 93 PFASs including perfluoroalkyl phosphonic acids/phosphinic acids and polyfluoroalkyl phosphate esters can be completed by single injection. Additionally, the present disclosure also provides a method to rapidly analyze 10 PFASs by GC-MS/MS.