Techniques are described for accelerating thermal equilibrium in a chromatographic column. An apparatus comprises a chromatography column, and a plurality of temperature control units in thermal contact with the chromatography column. A method of performing liquid chromatography comprises setting an inlet of a chromatography column to a first temperature using a first temperature control unit in thermal contact with said inlet, setting an outlet of the chromatography column to a second temperature using a second temperature control unit in thermal contact with the outlet, wherein the first temperature is less than the second temperature; and injecting a sample into a liquid stream that flows through the chromatography column after the inlet is set at the first temperature and the outlet is at the second temperature.

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.

In a process for thermally desorbing a phase material (20), in particular for conditioning a fiber for carrying out a solid-phase microextraction, the phase material (20) is heated along a temperature curve. The temperature curve of the phase material (20) during desorption includes at least one low point.

Disclosed herein are an amino acid analysis method and a liquid chromatographic apparatus for improving separation performance of threonine, serine, glycine, and alanine. The method of analyzing amino acids using the liquid chromatographic apparatus equipped with a cation exchange column includes a process for distributing a sample containing threonine, serine, glycine, and alanine as the amino acids, together with an eluent, to the cation exchange column to separate threonine, serine, glycine, and alanine, wherein a column temperature when separating threonine and serine is higher than a column temperature when separating glycine and alanine.

A chromatograph apparatus control device according to the present disclosure is a control device for controlling a chromatograph apparatus having the function of a liquid chromatograph and that of a supercritical fluid chromatograph. The control device includes a first-type method file creator configured to create a first-type method file describing a condition of an analysis by a liquid chromatograph; a second-type method file creator configured to create a second-type method file describing a condition of an analysis by a supercritical fluid chromatograph; and a batch file creator configured to create a single batch file including a plurality of records describing a group of method files including the first-type method file and the second-type method file, with one method file in each record.

The exemplary embodiments may determine a temperature set point for an outlet heater or cooler based on available information without requiring user input or requiring only minimal user input. The exemplary embodiments may estimate the temperature set point of the outlet heater based on available information, such as pressure delta along the column, temperature at the inlet of the chromatography column, and volumetric flow rate. In some instances, the estimate may be normalized for column dimensions, such as length and diameter. Tailing factor may also be used in determining the estimate. The estimate is not computationally burdensome and can be recalculated as the chromatography column is in use.

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.

In gas chromatography (GC), a sample is introduced into a flow of carrier gas and the mixture is driven through a heated GC column to acquire chromatographic data from the sample. During this time, the column is heated from an initial temperature to a final temperature. Subsequently, the column is cooled according to a cooling program. The cooling program may include a first cooling ramp, a subsequent isothermal hold, and a subsequent second cooling ramp. Alternatively, while the column is cooled down the flow of carrier gas through the column may be slowed down or ceased for a period of time, after which the flow of carrier gas through the column may be resumed at the original flow rate in preparation for processing another sample. Controlling column temperature and/or flow in this manner may be effective for reducing column bleed carryover and/or the effects thereof.

The invention relates to a method for analysing hydrocarbons, comprising: the implementation of a gas chromatography separation according to a first controlled temperature profile, to separate a sample into a plurality of analytes; the detection of at least one of said analytes by measurement of a variation of the resonance frequency of at least one resonator of nano-electromechanical system (NEMS) type covered with a functional layer made to vibrate at the resonance frequency thereof, under the effect of an adsorption or desorption of the analyte by the functional layer, said method being characterised in that the resonator is subjected to a second controlled temperature profile, lower than the first profile.

A temperature gradient chromatography, and apparatus for the same, said method comprising the following: a) dissolving a composition comprising at least one polymer in at least one solvent, to form a polymer solution; b) injecting at least a portion of the polymer solution onto a support material and wherein the support material has a CI from 0.70 to 1.50; c) cooling the support material at a rate greater than, or equal to, 0.2 C./min; d) increasing the temperature of the support material to elute at least some of the polymer; e) generating the chromatogram.