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.

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.

An autosampler sets an injection valve to be in a sample filling state when a sample loop is filled with a sample, and, after completion of filling with the sample, switches the injection valve to an intermediate state and first connects only one end of the sample loop to a liquid delivery channel and an analysis channel. After the above, the injection valve is switched to the sample injection state and the sample loop is interposed between the liquid delivery channel and the analysis channel, so that the sample is injected into the analysis channel.

Pressure-controlled splitting can be used to inject a chemical sample from an injection source to a detector (e.g., a mass spectrometer) for chemical analysis (e.g., gas chromatography or gas chromatography-mass spectrometry) with reduced peak widths. For example, the sample is first transferred to a first compression volume; then pressure in the system is increased to compress the sample to split it between a second compression volume and a column. The fraction of the sample split to the column can have reduced peak widths compared to the peak widths prior to compression and splitting yet can maintain the same peak height to preserve high sensitivity for trace level analysis. This portion of the sample can traverse the column and elute to the detector for analysis with reduced chemical noise. Faster injection rates can allow faster analysis times, as less separation of chemicals is needed before the sample reaches the detector.

Disclosed is a method for determining an operating flow rate for a chromatographic column (4) in an HPLC system (1). The method comprises: measuring/calculating a pressure of the system (1) without the chromatographic column (4) for one or more flow rates; fitting a function to the flow rate(s) and corresponding pressure(s), calculating from the function and a predetermined recommended flow rate for the chromatographic column (4) a system pressure drop at the predetermined recommended flow rate. An operating flow rate is determined by summing the system pressure drop and a maximal column pressure limit, and determining a contribution of the system pressure drop to the summed pressure. If this contribution exceeds 1% an operating flow rate for the column is determined to a flow rate that corresponds to a pressure at a pressure monitor arranged before the column that is lower than the predetermined maximum column pressure limit.

Disclosed is a method for determining an operating flow rate for a chromatographic column (4) in an HPLC system (1). The method comprises: measuring/calculating a pressure of the system (1) without the chromatographic column (4) for one or more flow rates; fitting a function to the flow rate(s) and corresponding pressure(s), calculating from the function and a predetermined recommended flow rate for the chromatographic column (4) a system pressure drop at the predetermined recommended flow rate. An operating flow rate is determined by summing the system pressure drop and a maximal column pressure limit, and determining a contribution of the system pressure drop to the summed pressure. If this contribution exceeds 1% an operating flow rate for the column is determined to a flow rate that corresponds to a pressure at a pressure monitor arranged before the column that is lower than the predetermined maximum column pressure limit.

A sampling needle (2) having a suction port at a tip, a movement mechanism (4) that moves the needle (2) at least in a vertical direction while holding the needle (2) in a state where the suction port faces vertically downward, a suction mechanism (6) for sucking liquid through the needle (2), a controller (10) configured to control operation of the movement mechanism (4) and the suction mechanism (6) are included. In sampling of liquid from a container (16) whose upper surface is opened, the controller (10) is configured to execute an inserting step of inserting the tip of the needle (2) into the liquid in the container (16) by lowering the needle (2) from above the container (16), a sucking step of sucking a predetermined amount of the liquid from the suction port of the needle (2) after the inserting step is completed, a pulling up step of pulling up the needle (2) from the liquid to position the suction port above a liquid level of the liquid after the sucking step is completed, and a shaking-off step of repeating shaking-off operation of lowering and suddenly stopping the needle (2) a plurality of times with standby time in which the needle (2) is completely stopped or raised in between while maintaining a state where the suction port is positioned above the liquid level after the pulling up step is completed.

A sampling needle (2) having a suction port at a tip, a movement mechanism (4) that moves the needle (2) at least in a vertical direction while holding the needle (2) in a state where the suction port faces vertically downward, a suction mechanism (6) for sucking liquid through the needle (2), a controller (10) configured to control operation of the movement mechanism (4) and the suction mechanism (6) are included. In sampling of liquid from a container (16) whose upper surface is opened, the controller (10) is configured to execute an inserting step of inserting the tip of the needle (2) into the liquid in the container (16) by lowering the needle (2) from above the container (16), a sucking step of sucking a predetermined amount of the liquid from the suction port of the needle (2) after the inserting step is completed, a pulling up step of pulling up the needle (2) from the liquid to position the suction port above a liquid level of the liquid after the sucking step is completed, and a shaking-off step of repeating shaking-off operation of lowering and suddenly stopping the needle (2) a plurality of times with standby time in which the needle (2) is completely stopped or raised in between while maintaining a state where the suction port is positioned above the liquid level after the pulling up step is completed.

A container assembly for use with a high-pressure liquid chromatography (HPLC) instrument is disclosed, in which the container assembly, when coupled to a source of pressurized gas, provides fluid medium to the HPLC instrument at positive pressure. The container assembly has an external exterior container shell, an internal fluid container for holding fluid medium, an interstitial volume between the external exterior container shell and the internal fluid container, a port for fluidly connecting the volume to a pressurized gas source, and a port for fluidly connecting the internal fluid container to the HPLC instrument. As a pressurized gas in the interstitial volume increases, fluid medium flows out of the port connected to the internal fluid bag and container assembly at a positive pressure. A system incorporating the container assembly, and method of use of the same, are also disclosed.

A container assembly for use with a high-pressure liquid chromatography (HPLC) instrument is disclosed, in which the container assembly, when coupled to a source of pressurized gas, provides fluid medium to the HPLC instrument at positive pressure. The container assembly has an external exterior container shell, an internal fluid container for holding fluid medium, an interstitial volume between the external exterior container shell and the internal fluid container, a port for fluidly connecting the volume to a pressurized gas source, and a port for fluidly connecting the internal fluid container to the HPLC instrument. As a pressurized gas in the interstitial volume increases, fluid medium flows out of the port connected to the internal fluid bag and container assembly at a positive pressure. A system incorporating the container assembly, and method of use of the same, are also disclosed.