A system and method for surface characterization of a porous solid or powder sample using flowing gas include mass flow controllers configured to deliver a controllable mass flow of a carrier gas and adsorptive gas to vary concentration of the adsorptive gas flowing through at least one measurement channel containing a sample cell. A concentration detector downstream of the sample cell provides a signal indicative of the adsorptive gas concentration to a controller that determines the amount of adsorptive gas adsorbed and/or desorbed to characterize the surface area, pore volume, pore volume distribution, etc. of the sample material. The detector may include a housing, heat exchanger, thermal conductivity detector, and a temperature regulator.

A system and method for surface characterization of a porous solid or powder sample using flowing gas include mass flow controllers configured to deliver a controllable mass flow of a carrier gas and adsorptive gas to vary concentration of the adsorptive gas flowing through at least one measurement channel containing a sample cell. A concentration detector downstream of the sample cell provides a signal indicative of the adsorptive gas concentration to a controller that determines the amount of adsorptive gas adsorbed and/or desorbed to characterize the surface area, pore volume, pore volume distribution, etc. of the sample material. The detector may include a housing, heat exchanger, thermal conductivity detector, and a temperature regulator.

An absorbance detector includes a sample cell, a light source for irradiating the sample cell, a photo sensor, an optical system for guiding light emitted from the light source to the sample cell and guiding light that has been transmitted through the sample cell to the photo sensor, a reference signal acquirer configured to acquire a detection signal of the photo sensor when the sample solution is not flowing through the sample cell as a reference signal for each analysis of the sample, a calculator configured to find absorbance of the sample based on a measurement signal obtained by the photo sensor in the analysis and the reference signal acquired for the analysis when an analysis of the sample is carried out, and an analysis data storage configured to associate data of the absorbance found by the calculator and data of the reference signal to each other for storage.

A response factor that is a signal strength ratio with respect to a reference compound for various compounds is previously stored in a response factor storage (22). When an operator instructs to estimate an analysis limit value, a measurement unit (1) performs GC-MS analysis on a sample containing the reference compound a plurality of times under control of an analysis controller (3). A signal strength calculator (23) obtains a signal strength value of the reference compound based on an analysis result of the measurement unit (1), a relative strength calculator (24) calculates a relative standard deviation from the plurality of measured signal strength values, and calculates the relative standard deviation of a target compound from the response factor of the target compound read from the response factor storage (22). An analysis limit value estimator (25) estimates a limit of detection (LOD) and the like from the relative standard deviation of the target compound by a known method, and displays the LOD on a display (6). Consequently, the analysis limit value can simply be obtained without actually measuring the target compound.

The detection of minute amounts of components that have been undetectable due to an influence of a mobile phase or reagents or the like added to the mobile phase is realized in LC-MS. At the outset, blank measurement is executed, and an m/z value M.sub.BG of a background signal derived from a mobile phase or the like is extracted on a mass spectrum obtained by the blank measurement (S2-S4). An analysis method is then created that executes scanning measurement in a plurality of divided m/z ranges in which the m/z value M.sub.BG of the background signal has been excluded from a predetermined m/z range. An LC/MS analysis of the target sample is executed according to the analysis method (S5-S6). When a total ion chromatogram (TIC) is created from data obtained by the LC/MS analysis, influence of the background signal hardly appears in the TIC, and the base line is lowered.

A method for surface characterization of a porous solid or powder sample using flowing gas includes a controller that controls mass flow of a carrier gas and an adsorptive gas to form a mixture having a target concentration of the adsorptive gas over the sample, determining adsorptive gas concentration based on signals from a detector disposed downstream of the sample, automatically repeating the controlling and determining steps for a plurality of different target concentrations, and generating an isotherm for the sample based on the adsorptive gas concentration for the plurality of different target concentrations. The method may include immersing the sample in liquid nitrogen to cool the sample for all, or at least a portion of each of the different target concentrations. The target concentrations may vary from less than 5% to greater than 95%, and may vary in a stepwise manner.

A method for surface characterization of a porous solid or powder sample using flowing gas includes a controller that controls mass flow of a carrier gas and an adsorptive gas to form a mixture having a target concentration of the adsorptive gas over the sample, determining adsorptive gas concentration based on signals from a detector disposed downstream of the sample, automatically repeating the controlling and determining steps for a plurality of different target concentrations, and generating an isotherm for the sample based on the adsorptive gas concentration for the plurality of different target concentrations. The method may include immersing the sample in liquid nitrogen to cool the sample for all, or at least a portion of each of the different target concentrations. The target concentrations may vary from less than 5% to greater than 95%, and may vary in a stepwise manner.

An analyzer capable of suppressing the generation of noise in a current detection circuit is provided. On a board 61, a current detection circuit 60 for processing an output signal from a detector is mounted. The cover member 63 has a space 630 in which the current detection circuit 60 is accommodated. A gas is supplied from a gas source into the space 630. The cover member 63 is provided with an inlet port 633 for introducing the gas from the gas source into the space 630 and an outlet port 634 for discharging the gas in the space 630.

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.

An improved version of the capillary bridge viscometer that compensates for the effect of solvent compressibility is disclosed. A novel, yet simple and inexpensive modification to a conventional capillary bridge viscometer design can improve its ability to reject pump pulses by more than order of magnitude. This improves the data quality and allows for the use of less expensive pumps. A pulse compensation volume is added such that it transmits pressure to the differential pressure transducer without sample flowing there through. The pressure compensation volume enables the cancellation of the confounding effects of pump pulses in a capillary bridge viscometer.