A method for determining the content of menthol in a traditional Chinese medicine composition. The traditional Chinese medicine composition consists of the following medicinal materials: Fructus Forsythia, Flos Lonicerae, Radix Isatidis, Semen Armeniacae Amarum, menthol, Herba Houttuyniae, rheum, Herba Pogostemonis, Rhizoma Dryopteris Crassirhizomae, Rhodiola rosea L., Herba Ephedrae, Radix Glycyrrhizae and gypsum. In the method for determining the content, the content of the menthol in the composition is determined by gas chromatography to effectively control the content of menthol in the composition, and the method can save energy and reduce the costs for analysis.

A liquid chromatograph includes: a liquid meter that measures a liquid amount of a mobile phase stored in one or more mobile phase containers; and a notification unit that notifies an operator of the liquid amount of the mobile phase in each of the one or more mobile phase containers measured by the liquid meter. According to such a liquid chromatograph, when the operator replenishes the mobile phase to the mobile phase container, it is not necessary to visually measure the liquid amount of the mobile phase or manually input the value to the control device, so that it is possible to reduce the workload of the operator regarding the liquid amount management of the mobile phase.

A liquid chromatograph includes: a liquid meter that measures a liquid amount of a mobile phase stored in one or more mobile phase containers; and a notification unit that notifies an operator of the liquid amount of the mobile phase in each of the one or more mobile phase containers measured by the liquid meter. According to such a liquid chromatograph, when the operator replenishes the mobile phase to the mobile phase container, it is not necessary to visually measure the liquid amount of the mobile phase or manually input the value to the control device, so that it is possible to reduce the workload of the operator regarding the liquid amount management of the mobile phase.

Certain embodiments described herein are directed to chromatography systems that include a microfluidic device. The microfluidic device can be fluidically coupled to a switching valve to provide for selective control of fluid flow in the chromatography system. In some examples, the microfluidic device may include a charging chamber, a bypass restrictor or other features that can provide for added control of the fluid flow in the system. Methods of using the devices and methods of calculating lengths and diameters to provide a desired flow rate are also described.

Certain embodiments described herein are directed to chromatography systems that include a microfluidic device. The microfluidic device can be fluidically coupled to a switching valve to provide for selective control of fluid flow in the chromatography system. In some examples, the microfluidic device may include a charging chamber, a bypass restrictor or other features that can provide for added control of the fluid flow in the system. Methods of using the devices and methods of calculating lengths and diameters to provide a desired flow rate are also described.

Provided is a unit-type analyzer (1) including: a system controller (80); a plurality of analyzing units (60), with each analyzing unit including a main power switch (70) configured to turn on and off electric power to the analyzing unit, and a software switch (66) provided separately from the main power switch configured to turn on and off a communication with the system controller; and a software-switch operation-mode setter (65) configured to perform a setting for enabling or disabling an operation on the software switch included in each analyzing unit.

Provided is a unit-type analyzer (1) including: a system controller (80); a plurality of analyzing units (60), with each analyzing unit including a main power switch (70) configured to turn on and off electric power to the analyzing unit, and a software switch (66) provided separately from the main power switch configured to turn on and off a communication with the system controller; and a software-switch operation-mode setter (65) configured to perform a setting for enabling or disabling an operation on the software switch included in each analyzing unit.

Described is a metering pump that may be used to meter volumes of sample in a chromatography system. The metering pump has a modular configuration that allows for separation of a head pod from a drive assembly for easy serviceability. The head pod includes a pump head, cartridge housing, seal wash housing and plunger. The drive assembly can be implemented in an inline drive configuration. Alternatively, the drive assembly can be implemented in an offset drive configuration in which a stepper motor is displaced laterally from other drive assembly components but is coupled through a belt and pulley system.

Described is a metering pump that may be used to meter volumes of sample in a chromatography system. The metering pump has a modular configuration that allows for separation of a head pod from a drive assembly for easy serviceability. The head pod includes a pump head, cartridge housing, seal wash housing and plunger. The drive assembly can be implemented in an inline drive configuration. Alternatively, the drive assembly can be implemented in an offset drive configuration in which a stepper motor is displaced laterally from other drive assembly components but is coupled through a belt and pulley system.

Provided is a supercritical fluid apparatus including: an analysis flow path through which a mobile phase flows; a back-pressure control valve provided at a downstream end of the analysis flow path to adjust pressure in the analysis flow path to a predetermined pressure; a small-diameter pipe connected to the outlet of the back-pressure control valve, having an inner diameter allowing internal pressure to be maintained at a pressure higher than the atmospheric pressure; a large-diameter pipe connected to a downstream end of the small-diameter pipe, having a larger inner diameter than the small-diameter pipe; and a large-diameter pipe heating part for heating the large-diameter pipe.