Abstract: This invention concerns a chamber for chromatographic analyses, in which capillary columns, in particular columns of fused silica, are thermally conditioned. The chamber comprises a thermally insulated space which can be perfectly sealed towards the outside and which houses means for heating the air and at least a fan for air circulation inside said space. In order to make the air flow going to the column(s) within the chamber as homogeneous and stable as possible from the thermal viewpoint the heating means are positioned on the suction side of the fan or of each fan, so to cause a perfect mixing of cold and hot fluid flow threads or lines in correspondence with the fan itself, and thereby obtain a uniform and stable air current from the fan towards the column.

Abstract: A method for performing porosimetric analyses and apparatus therefor are disclosed. In particular, a method for performing porosimetric anaylses by the so-called mercury method is disclosed, wherein volumetric variations of mercury placed in a vessel are recorded. These variations are due to mercury penetration into the pores of a solid sample placed in the vessel under the mercury pressure variations. In the method disclosed, additional porosimetric information is obtained by reducing the pressure from a maximum value as a predetermined function of time. For example, the pressure reduction can be at a constant rate. Simultaneously, volume variations of the mercury exiting the sample pores are detected as the pressure decreases.

Abstract: An apparatus for controllably and reproducibly introducing, small amounts of a liquid sample into chromatographic systems, especially high resolution gas chromatographic systems with cold injection, thin-layer chromatographic systems and high resolution liquid chromatographic systems, in order to obtain sampling extremely reduced in volume and presenting maximum reliability and reproducibility, uses a sample container having a pipette-like or nozzle-like outlet neck of very small diameter. The liquid placed in the container is submitted to at least one pressure pulse which is controlled in duration and/or amplitude in order to determine emission of a corresponding and controlled quantity of liquid from the outlet neck.

Abstract: The invention relates to a modified-flame thermionic detector for gas chromatographs, of the type including a burner nozzle, an excitation electrode and a collecting electrode. The electrical connections of the nozzle and the excitation electrode can be changed at the operator's will, together with the spatial position of the excitation electrode with respect to the flame and the collector, to find out the presence of certain compounds, leaving all other conditions of analysis performance and detector supply unaltered. This allows obtaining chromatograms of unknown samples under different conditions of the detector configuration, to put into evidence the presence of certain compounds in the sample by comparing peaks of chromatograms obtained under said different operating conditions of the detector.

Abstract: A method and apparatus for controllably and reproducibly introducing small amounts of a liquid sample into chromatographic systems, especially high resolution gas chromatographic systems and thin-layer chromatographic systems, order to obtain sampling extremely reduced in volume and presenting maximum reliability and reproducibility, uses a sample container having a pipette-like or nozzle-like outlet neck of very small diameter. The liquid placed in the container is submitted to at least one pressure pulse which is controlled in time and/or amplitude in order to determine emission of a corresponding and controlled quantity of liquid from the outlet neck. The pressure pulse can be a pneumatic pulse directly applied to the liquid sample in the container, or a mechanical pulse applied to the liquid sample through a device acting by magnetostriction or by a piezoelectric system.

Abstract: An apparatus for controlling the injection passage of on-column injector is disclosed. The apparatus includes a valve having at least one channel inside it and leading to the injection passage for the injection syringe needle. The channel is connected outside the injector to a source for carrier gas introduction, when the valve is open, or to the atmosphere, when the valve is closed, so as to allow a quick-type injection without the drawbacks of this injection type, as well as to have a solvent exhaust after injection.

Abstract: This invention relates to a method and a device for vaporization injection of a liquid sample in a gas chromatographic column housed in an oven comprising a direct on column injector suitable for injecting a liquid sample into the initial zone of a capillary column and capable of pneumatically sealing the injection port at the end of injection. Between the injector and the gas chromatographic column itself an uncoated capillary column length is provided in which vaporization of the injected sample occurs using heat from an oven housing said capillary column length, said oven being the same or separate from the oven containing said gas chromatographic column.

Abstract: A device is disclosed for coordinating the position of an injection syringe needle in a gas chromatographic apparatus with at least one other operation of the gas chromatographic apparatus downstream of the device. The device comprises a first channel for introducing the injection syringe. The first channel is substantially aligned with the injection channel of a gas chromatographic injector.

Abstract: The invention concerns a device for picking up liquid samples to be analyzed, especially in automatic samplers, said device comprising a needle connected to a sucking pump and supported by a support which moves said needle downwards to pick up the sample from a vial containing same and upwards from said vial. In order to perform a washing step after one aspiration and before the subsequent one, the needle support is designed to perform an oscillating movement when the support is in its upward position with respect to the vial. The oscillating movement is performed by the cooperation of cam means and a control rod having at least a pivot axis controlling the alternative movements. The oscillating movement makes the needle plunge into a sidewardly positioned trough containing a washing liquid.

Abstract: A method and apparatus for the quantitative determination of very small percentages of sulphur in sample analysis is carried out by means of sample combustion in a helium current temporarily enriched with oxygen, subsequent catalytic oxidation and reduction of the combustion gases, gas chromatographic separation and detection in a thermal conductivity detector. At the outlet of this thermal conductivity detector the products are fed to a water trap and to a sulphur selective detector of the flame photometric type to detect sulphur contents below 0.5 .mu.g.

Abstract: A gas chromatographic chamber in the form of an oven is disclosed, including an outer envelope including insulated walls defining the chromatographic chamber which can be made air tight, an inner housing section within that chamber for housing the chromatographic column, and including an air distributor to maintain the uniform distribution of air within the inner housing section, as well as a heater to heat the air therein, non-thermally insulating partitions within the chamber and spaced from the insulated wall to provide a pneumatically insulated space between the insulated walls and the inner housing section, and a fluid circulator to create the controlled circulation of fluid within the pneumatically insulated space to effect the temperature within the inner housing section.

Abstract: An apparatus for porosimetric measurements, wherein a sample to be analyzed is put in an ampoule filled with mercury and submitted to ever increasing pressures, in order to obtain measurements of the mercury volume variations due to pressure increases.Such mercury volume variations, which are correlated to the sample pore sizes, are detected by measuring capacity variations in a mercury condenser provided for in a capillary neck of ampoule.

Abstract: An apparatus for feeding carrier gas at a constant rate to on-column injectors for capillary and micropacked gas-chromatographic columns. The apparatus includes a constant pressure gas delivering device in operation during the sample injection, and a constant rate gas delivering device in operation during the sample processing stage inside the column. The two devices are connected in parallel and a switch controls the alternative operation of the same.

Abstract: A method and device for sample injections into a gas chromatographic column, wherein, in order to achieve sample trapping and solvent effects, the injection zone and an initial portion of the column are kept at a low temperature and then a quick temperature change is performed at the end of said initial portion. The cooling action is preferably performed by a cooling fluid acting outside the injector and column, while said temperature change is obtained by a suitable thermoregulation of the oven wherein said gas chromatographic column is housed.