This disclosure provides liquid chromatography tandem mass spectrometer (LC-MS/MS) methods and systems for detecting low levels of pesticides and mycotoxins in a test sample. In the disclosed methods and systems, oxalic acid is added to a mobile phase composition of a reverse phase chromatographic separation column. This addition improves the signal for certain pesticides and mycotoxins by a factor of from 1.5 to 9, improving their detection limits in a variety of test samples.

A liquid chromatograph analysis method and a liquid chromatograph minimize analysis time when performing analyses by switching columns and mobile phases. Liquid chromatograph 100 for performing a plurality of analyses according to a schedule table includes: mobile phase switching sections 15, 16 for switching a plurality of mobile phases to select a mobile phase to be used in analysis; column switching sections 31, 33 for switching a plurality of columns 32a-32f to select a column to be used in analysis; and control section 60 including memory 61 for storing an equilibration time of each of the plurality of columns 32a to 32f and an equilibration controller 66 for controlling column equilibration. If used columns or used mobile phases are different between two consecutively executed analyses, equilibration controller 66 equilibrates a column used in the later of the two analyses over an equilibration time read out from memory 61.

The present disclosure is directed to methods for performing size exclusion chromatography. Embodiments of the present disclosure feature methods for improving separations of proteinaceous analytes in size exclusion chromatography, for example, by using low concentrations of amino acids or derivatives thereof in the mobile phase.

A liquid delivery device includes a liquid delivery pump that sucks a mobile phase, which is liquid, from a mobile phase container containing the mobile phase through a suction pipe whose end is immersed in the mobile phase in the mobile phase container, and feeds the mobile phase, and at least one dissolved substance removal filter that is provided at a position upstream of the liquid delivery pump on a path through which the mobile phase flows and is filled with a filler having the property of adsorbing a dissolved substance in the mobile phase.

In various aspects provided are purification media and containers for dispensing a purified liquid are provided herein where a high surface area-to-volume chemically interactive purification media positioned at the outlet of a container that purifies the liquid as it is dispensed and/or extracted.

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.

A liquid delivery device includes a liquid delivery pump that sucks a mobile phase, which is liquid, from a mobile phase container containing the mobile phase through a suction pipe whose end is immersed in the mobile phase in the mobile phase container, and feeds the mobile phase, and at least one dissolved substance removal filter that is provided at a position upstream of the liquid delivery pump on a path through which the mobile phase flows and is filled with a filler having the property of adsorbing a dissolved substance in the mobile phase.

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.

A method of controlling the impurities in a cyclosporin A eye gel. A high performance liquid chromatography is performed, and chromatographic conditions are as follows: the detection wavelength is 210-230 nm; the column temperature is 60-68? C.; the flow rate is 0.8-1 ml/min; and the mobile phase A is: THF-water-phosphoric acid. The method of controlling impurities solves the problem of excipients interference and separation of many impurities at the same time, it also provides an effective method for the formulation of quality standard of impurities in this kind of preparation.

In various aspects provided are purification media and containers for dispensing a purified liquid are provided herein where a high surface area-to-volume chemically interactive purification media positioned at the outlet of a container that purifies the liquid as it is dispensed and/or extracted.