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.

The present disclosure relates to techniques for detecting leaks in a pump. A compressed fluid, such as compressed CO.sub.2, is provided through a first channel formed within a pump head. The compressed fluid within the first channel is in contact with at least a portion of a pump piston, and the first channel is substantially sealed using a fluid seal positioned around a portion of the pump piston. A wash fluid is pumped into a second channel formed within a wash seal housing associated with the pump head using a fluid pump. The wash fluid within the second channel surrounds a portion of the pump piston and is separated from the first channel by the fluid seal. A flow rate of fluid exiting the wash seal housing via the second channel is measured, and the existence of a leak is determined based on the measured flow rate.

A gas-phase chemical analyzer has at least one gas chromatography column in gas-flow communication with at least one gas carrying tube of an optical absorption cell, a laser for illuminating molecules in a gas mixture flowing though the at least one gas carrying tube of the optical absorption cell, and a photodetector or photodetecting apparatus for measuring absorption spectra of the gas mixture illuminated by the laser. A first module is provided for statically identifying particular molecules in the gas mixture from other molecules in said gas mixture and a second module is provided for comparing at least selected ones of the particular molecules in the gas mixture with a reference library of absorption spectra of previously identified molecules and for determining the likelihood of a correct identification of the particular molecules in the gas mixture and the previously identified molecules in the reference library.

A gas-phase chemical analyzer has at least one gas chromatography column in gas-flow communication with at least one gas carrying tube of an optical absorption cell, a laser for illuminating molecules in a gas mixture flowing though the at least one gas carrying tube of the optical absorption cell, and a photodetector or photodetecting apparatus for measuring absorption spectra of the gas mixture illuminated by the laser. A first module is provided for statically identifying particular molecules in the gas mixture from other molecules in said gas mixture and a second module is provided for comparing at least selected ones of the particular molecules in the gas mixture with a reference library of absorption spectra of previously identified molecules and for determining the likelihood of a correct identification of the particular molecules in the gas mixture and the previously identified molecules in the reference library.

A sensor module includes a sensor configured to detect a specific substance in a sample, a first channel, and a second channel The first channel supplies a first fluid as the sample to the sensor. The second channel supplies a second fluid different from the first fluid to the sensor. The second channel includes a second fluid buffer tank for holding the second fluid for a fixed time interval.

A sensor module includes a sensor configured to detect a specific substance in a sample, a first channel, and a second channel The first channel supplies a first fluid as the sample to the sensor. The second channel supplies a second fluid different from the first fluid to the sensor. The second channel includes a second fluid buffer tank for holding the second fluid for a fixed time interval.

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.

A chromatography analysis system includes a liquid delivery pump (2), an autosampler (4), a separation column (12), a column oven (6), a detector (8). The chromatography analysis system further comprising a shutdown execution part (22) configured to start shutdown to finally stop driving of the liquid delivery pump (2) and temperature control operation of the column oven (6) at a time when a predetermined situation occurs, by controlling operation of the liquid delivery pump (2) and the column oven (6), and a column protection temperature setter (24) configured to set a column protection temperature for preventing deterioration of the separation column (12) due to overheating. The shutdown execution part (22) is configured to stop driving of the heater (14) in a state where the liquid delivery pump (2) is driven when the shutdown is started, and then, stop driving of the liquid delivery pump (2) after a temperature of the internal space detected by the temperature sensor (18) becomes equal to or less than the column protection temperature.

A chromatography analysis system includes a liquid delivery pump (2), an autosampler (4), a separation column (12), a column oven (6), a detector (8). The chromatography analysis system further comprising a shutdown execution part (22) configured to start shutdown to finally stop driving of the liquid delivery pump (2) and temperature control operation of the column oven (6) at a time when a predetermined situation occurs, by controlling operation of the liquid delivery pump (2) and the column oven (6), and a column protection temperature setter (24) configured to set a column protection temperature for preventing deterioration of the separation column (12) due to overheating. The shutdown execution part (22) is configured to stop driving of the heater (14) in a state where the liquid delivery pump (2) is driven when the shutdown is started, and then, stop driving of the liquid delivery pump (2) after a temperature of the internal space detected by the temperature sensor (18) becomes equal to or less than the column protection temperature.