When a liquid in the column is replaced by carbon dioxide in a supercritical state in the chromatograph, an operation of a first pump is controlled by a flow rate control unit, and the carbon dioxide in the supercritical state is supplied at a constant pressure. Moreover, when a flow rate of the carbon dioxide in the supercritical state reaches a predetermined flow rate thereafter, the flow rate control unit controls an operation of the first pump so that the carbon dioxide in the supercritical state is supplied at a constant flow rate.

Systems for use with liquid chromatography for provision of continuous flow or gradient flow in connection with two pumps providing mobile phase to a valve.

An autosampler is switched selectively between an injecting mode where a sampling flow path is incorporated into an analysis flow path of a liquid chromatograph and a loading mode where the sampling flow path is not incorporated into the analysis flow path and injects a sample into the analysis flow path at a position farther upstream than a separation column by being switched to the injecting mode with the sample held in the sampling flow path, and includes a clog determiner configured to acquire a sending liquid pressure of a liquid sending pump that sends a mobile phase in the analysis flow path, obtain a variation value of the liquid sending pressure when the injecting mode and the loading mode are switched and determine presence or absence of a clog in a system incorporated into the analysis flow path in the injecting mode based on the obtained variation value.

An analysis assistance method includes setting pressure in a first BPR to a value higher than a prescribed second set value with pressure in a second BPR set to a second set value, instructing a supercritical fluid chromatograph to supply a mobile phase to a supply flow path at a flow rate of the mobile phase that is to be theoretically supplied to a first flow path when the mobile phase is supplied to the supply flow path at a prescribed total flow rate and a prescribed sample introduction ratio, and gradually decreasing a set value of the pressure in the first BPR, and detecting a set value of the pressure in the first BPR at the time when supply of the mobile phase to a second flow path is stopped due to a decrease in set value of the pressure in the first BPR, as a first set value.

Disclosed is a liquid chromatography system and mixer for use therein that includes a first split connected to an inlet, the first split branching the flow of fluid from the inlet into a first path and a second path; a second split connected to an outlet of the first path, the second split branching the first path into a third path and a fourth path; and a third split connected to an outlet of the second path, the third split branching the second path into a fifth path and a sixth path. The first path and the second path are offset by a first predetermined volume, the third path and the fourth path are offset by a second predetermined volume, and the fifth path and the sixth path are also offset by the second predetermined volume.

The invention relates to a system and micro monitor apparatus, a space-, time-, and cost-efficient device to concentrate, identify, and quantify organic compounds in gas environments. The invention further relates to a method centered on gas chromatography for identifying and quantifying organic compounds in gas environments, using air as the carrier gas, without the need for a compressed pre-bottled purified carrier gas.

Disclosed herein are various embodiments of a pump mechanism comprising a rigid structure having an open end and a closed end, a plunger disposed in the open end of the rigid structure, and a flexible, fluid-proof sheet of material attached to an inner wall of the rigid structure and bonded to the head of the plunger such as to form a fluid barrier between the interior of the rigid structure and the plunger. Movement of the plunger toward the closed end of the rigid structure causes a rolling corner to be formed between the head of the plunger and the rigid structure and a fluid contained within the pump chamber to be forced out of the pump chamber via a fluid port defined in the closed end of the rigid structure.

The plunger of the present disclosure includes: a plunger main body section that is made of sapphire, has a pillar shape, and includes a non-penetrating fitting hole extending in a central axis direction from one end portion; a core portion that is inserted into the fitting hole and has a higher thermal conductivity than sapphire; and a joint layer that is interposed between an inner peripheral surface and a bottom surface of the fitting hole of the plunger main body section, and an outer peripheral surface and a tip surface of the core portion, the joint layer being configured to bond the plunger main body section and the core portion. A pump includes the plunger. A liquid analysis device includes the pump.

A method of controlling a sample separation apparatus, for separating a fluidic sample using a mobile phase provided from at least one mobile phase container, includes determining a weight and volume reduction behavior according to which weight and volume of mobile phase in a mobile phase container are reduced during conveying mobile phase from the mobile phase container in the sample separation apparatus, and determining a tare weight of the mobile phase container based on a gross weight information, a volume information, and the determined weight and volume reduction behavior. The gross weight information is indicative of an initial gross weight of the mobile phase container including its mobile phase, and the volume information is indicative of an initial mobile phase volume in the mobile phase container.

A first mixer mixes solvents therein. A second mixer has a capacity different from that of the first mixer, and mixes solvents therein. A first separation column is associated with the first mixer. A second separation column is associated with the second mixer. A first valve enables switchover between a first communication state in which the first mixer and the first separation column communicate with a detector, and a second communication state in which the second mixer and the second separation column communicate with the detector. Only by switching the first valve, it is possible to switch between the first communication state and the second communication state. The internal capacity of a flow channel in the first communication state differs from that in the second communication state. Therefore, it is easy to perform analysis with different internal capacities.