A gas chromatograph includes first and second sample vaporization units, first and second separation columns, first and second carrier gas suppliers, a column oven that contains the first and second separation columns and has a first heater, first and second detectors, a first auxiliary gas supplier that supplies an auxiliary gas to the first separation column and a controller that executes control by increasing a supply pressure of an auxiliary gas applied by the first auxiliary gas supplier to a pressure higher than a pressure during an analysis of a sample and lowering a supply pressure of a carrier gas applied by the first carrier gas supplier to a pressure lower than a pressure during the analysis of the sample such that the supply pressure of the auxiliary gas is higher than the supply pressure of the carrier gas, and sets a first maintenance switch mode in which the first sample vaporization unit is maintainable.

A microfluidic device for separating a phase in a specimen has been described. This is based on a microfluidic trapping area, channels connected to it and integrated inputs and outputs connected onto the channels. An additional integrated input is provided which allows the flow in the device to be controlled and which may prevent leaking of the specimen and the phase.

A gas chromatograph includes first and second sample vaporization units, first and second separation columns, first and second carrier gas suppliers, a column oven that contains the first and second separation columns and has a first heater, first and second detectors, a first auxiliary gas supplier that supplies an auxiliary gas to the first separation column and a controller that executes control by increasing a supply pressure of an auxiliary gas applied by the first auxiliary gas supplier to a pressure higher than a pressure during an analysis of a sample and lowering a supply pressure of a carrier gas applied by the first carrier gas supplier to a pressure lower than a pressure during the analysis of the sample such that the supply pressure of the auxiliary gas is higher than the supply pressure of the carrier gas, and sets a first maintenance switch mode in which the first sample vaporization unit is maintainable.

A system for concentrating an analyte gas in a gas stream of an analytical system is provided. The system comprises at least one separation device, at least one gas inlet line, at least one detector, at least one gas outlet line, a first split line in connected to the gas inlet line, and a first split valve for controlling gas flow in the first split line. Also provided is a method for concentrating an analyte gas.

A microfluidic device for separating a phase in a specimen has been described. This is based on a microfluidic trapping area, channels connected to it and integrated inputs and outputs connected onto the channels. An additional integrated input is provided which allows the flow in the device to be controlled and which may prevent leaking of the specimen and the phase.

A liquid chromatograph has a mobile phase delivery section including, between mobile phase channels connected respectively to a plurality of mobile phase containers and a delivery pump, channel switching valves for selecting one of the mobile phase channels. This liquid chromatograph whose channel switching valves have a hierarchical structure including at least two stages includes a valve connection state setting section that is configured to set the connection state between the channel switching valves and the connection state between the channel switching valves and the mobile phase channels, and further includes a per channel total delivery amount calculation section that is configured to calculate the total delivery amount of mobile phase per mobile phase channel based on a connection state according to the valve connection state setting section, the delivery amount per unit time by the delivery pump, and the operation time of the delivery pump.