Abstract: Elemental analysis of a sample is carried out in an oxygen atmosphere in a combustion reactor and the volume of oxygen required for analysis is determined by means of the algorithm Qo=&Dgr;(Qc)  [1] where Qo is the volume of oxygen required and Qc is the weight of the sample to be analyzed and &Dgr;=Qo1/Qc1 where Qo1 is the volume of oxygen necessary for the combustion of a predetermined quantity Qc1 of the sample to be analyzed, the volume of oxygen Qo is then fed in pulsed mode to the combustion reactor, by means of a flow detector.

Abstract: A method and device for vaporization injection in which there is at least one constriction between the end of the sample injection needle or tube and the interior of the heated vaporization chamber. The terminal part of the needle or tube can be heated to improve nebulisation of the sample and therefore its vaporization speed.

Abstract: In elemental analysers with a valve control system of inert gas and oxygen supply, which opens the oxygen supply at preset moments, with regard to the introduction of the sample into the combustion reactor, the oxygen supply is controlled by the detection, over time, of at least one of the parameters, whose variation is determined by flash combustion in the combustion reactor, closing the oxygen supply depending on said state over time. The parameters are brightness, temperature and pressure in the combustion chamber and/or pressure upstream the combustion chamber.

Abstract: This invention concerns a method, a device, and an apparatus to detect changes of state in a capillary tube, in particular a gas-chromatographic column or pre-column and to consequently control the conditions under which samples are injected or introduced. The detection is carried out through changes in the temperature of the capillary tube, and/or changes in pressure, or flow rate of the carrier gas. The invention further concerns a method to control gas-chromatography functions by means of a specially designed software, based on the above-mentioned detections on a sample apparatus.

Abstract: A device for measuring the thermal conductivity of a fluid comprising a first detection section with at least one duct in which a gas flows and at least one heat sensitive resistance element placed in that duct, and a second detection section for the detection of an electrical resistance of the heat sensitive resistance elements. The device also comprises a thermoregulator to maintain the first detection section at a constant first temperature and a further thermoregulator to maintain at least part of the second detection section at a constant second temperature independent of the first temperature.

Abstract: The invention concerns a method for the realignment of peaks in gas chromatographic analyses after the replacement of the used capillary column with a nominally equal one, wherein a K coefficient characteristic of the column is preventively calculated by flowing carrier gas in the column under stabilized conditions of pressure and flow rate and of the column temperature, said K coefficient being stored in a memory of the gas chromatographic system. Said K coefficient is used to correlate at least two of the above mentioned parameters in subsequent analyses, obtaining an automatic realignment of peaks. The invention also concerns the analytical equipment to perform the method, and the capillary gas chromatographic column characterized as reported above.

Abstract: The invention concerns a device for vaporizing injections of samples into a gas chromatography analysis device, comprising a vaporization chamber elongated lengthways and heated, as well as a syringe equipped with a needle, the device being of the type in which the introduction of the sample is carried out without prior vaporization of the sample within the needle, and also foresees at least one stop and vaporization means for the liquid inside the vaporization chamber. To improve the conditions of vaporization and the transfer of the sample, the distance between the free end of the needle and the stated stop and vaporization means for the liquid is greater than 55 mm.

Abstract: A gas chromatography oven is endowed with a shutter for the influx of air from the outside and a pair of shutters for the controlled outflow of air from the oven, the shutters being positioned on the rear wall of the oven, near the corners of the rear wall. On the upper wall of the oven, at least one injector of the sample to be analyzed and at least one detector are lodged in a removable drawer.

Abstract: To inject a liquid sample with large volume into a GC column of a gas chromatograph, its volatile portion is evaporated by heat, in a non-selective way, in a vaporization chamber, the vapors thus generated being fed to pre-column located upstream of the GC column and maintained at a lower temperature to that of the vaporization chamber, where such compounds are separated from the solvent vapors, which are unloaded into the atmosphere while the compounds to be analyzed are sent to the GC column.

Abstract: The invention relates to a method and a device to control the physical conditions of the solvent within a pre-column, in a gas chromatography analysis apparatus. To achieve desired and controlled conditions of recondensation in the pre-column with vaporization injectors or of vaporation with "on-column" injectors, the dew-point of the solvent in the pre-column is calculated and the factors which influence this dew-point are varied and/or the temperature of the pre-column is varied, in order to set such temperatures in a desired correlation.

Abstract: A device and method are described for the gas chromatographic separation of a sample, aimed in particular at the analysis of large volume samples. Provision is made for the use of calculating and memorizing a plurality of reference values corresponding to the evaporation rates of solvents combined with a carrier gas for a corresponding plurality of discrete values representing the conditions of pressure, temperature, injected sample volume and sample injection rate. The effective solvent evaporation rate is then calculated in correspondence to the effective conditions in which the process is carried out to determine the volumetric fraction of the sample which is transferred through the capillary column in relation to its characteristics and geometrical dimensions.