Abstract: The present invention relates to a method for injecting a sample (i.e. a material to be analyzed that may be dissolved in a solvent) in a vaporization chamber or in a pre-column or a gas chromatograper, this method implying separately injecting a co-solvent, with the co-solvent being injected in advance of the sample and/or in a point in the vaporization chamber other than the sample injection point.

Abstract: The present invention relates to a method for injecting a sample (i.e. a material to be analyzed that may be dissolved in a solvent) in a vaporization chamber or in a pre-column or a gas chromatograper, this method implying separately injecting a co-solvent, with the co-solvent being injected in advance of the sample and/or in a point in the vaporization chamber other than the sample injection point.

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 (FIG. 1).

Abstract: A vaporization injector for gas chromatography analysis instruments, of the type including a vaporization chamber, heated or which may be heated, with a longitudinally elongated shape, a device for hermetically inserting the needle of a syringe containing the sample (substance to be analysed and solvent) into the chamber, a connection for feeding a carrier gas into the chamber and a gas chromatography capillary column with an upstream end open inside the vaporization chamber. In order to allow the vaporization of large sample volumes, the upstream end of the gas-chromatography column and the injection point of the sample into the vaporization chamber are both arranged adjacent to one of the longitudinal ends of the vaporization chamber and the feed connection for the carrier gas is located adjacent to the other end.

Abstract: A method and an apparatus for chromatography are described, wherein at least one element in electrically conductive material is provided to heat the capillary column in a direct way and wherein the control of the temperature is carried out according to a mathematical model having a component of predictive type, or Feed Forward type, that describes the thermodynamic behavior of the assembly comprising the electrically conductive element and the column at least as a function of the thermal resistance and the thermal capacity of the assembly thus constituted in order to regulate the supply of electrical power supplied to the conductive element.

Abstract: A method and an apparatus for chromatography are described, wherein at least one element in electrically conductive material is provided to heat the capillary column in a direct way and wherein the control of the temperature is carried out according to a mathematical model having a component of predictive type, or Feed Forward type, that describes the thermodynamic behavior of the assembly comprising the electrically conductive element and the column at least as a function of the thermal resistance and the thermal capacity of the assembly thus constituted in order to regulate the supply of electrical power supplied to the conductive element.

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: 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: 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: The invention concerns a method and an apparatus for the direct injection of large volumes (>3 &mgr;l) of samples into the column in a gas chromatography analysis apparatus comprising an oven, a gas chromatography column lodged in the oven, a means for the direct transfer into the column of the sample and a source of carrier gas upstream the column, as well as a detector downstream the column. According to the invention two or more of the parameters: nature of the solvent injection rate flow-rate and/or pressure of the carrier gas temperature at least of an initial length of the column during the injection are correlated and/or controlled to achieve a control of the length of the zone wetted by the sample during its introduction.

Abstract: There is provided a method and apparatus for controlling the carrier gas flow through a gas chromatographic apparatus with capillary column subjected to variations in temperature, through control of feeding pressure achieved following computerized processing of the equation of the carrier flow rate as a function of inlet pressure, column temperature and system structural parameters, including preliminary determination of the system parameters through detection of pressure, temperature and flow rate values in stabilized conditions of carrier passage through apparatus and calculation of a constant representing said parameters on the basis of values detected and in application of the aforesaid equation; storage of aforesaid constant; utilization of constant in the mentioned equation for controlling carrier flow rate through calculation and control of its feeding pressure during utilization of the gas chromatographic apparatus.

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.

Abstract: The invention concerns a process and a device for splitless vaporizing injection of samples into equipments of gas chromatographic analysis.The technique is applied specially when liquid samples generate volumes of vapors which cannot be housed inside the vaporizing chamber.Inside the vaporisation chamber, kept at high temperature, evaporation of the sample solvent forms a cool zone where the solutes are retained while the solvent vapors expand out of the vaporizing chamber and leave the injector. The sample liquid is kept in place within the vaporization chamber by suitable obstacles or by a packing material. At the end of solvent evaporation, i.e. when cooling ceases, the injection zone returns to the regulated injector temperature and the compounds to be analysed are transferred to the column by the carrier gas.

Abstract: An injector with a vaporization chamber for gas chromatographic apparatus includes a heater to heat the chamber and a pierceable septum to seal an end of the chamber. At least a heat conducting element is removably mounted between the septum and the heater. One or more elements are positioned adjacent to the septum and are in fluid communication with a source of carrier gas and a discharge outlet. The elements define paths with forced run for washing the septum and for feeding the vaporization chamber.

Abstract: The present invention relates to devices and processes for the introduction of a liquid sample into an apparatus for gas chromatographic analysis. A sample is injected into a vaporization chamber positioned upstream of a gas chromatographic column. The vaporization chamber is equipped with a means to feed a carrier gas selectively into the chamber, the chamber being kept at a temperature at least equal to the boiling temperature of the solvent at the operating pressure. A separation is effectuated between the sample and its carrier solvent, the solvent vapor is exhausted through an exhaust duct. Thereafter, the flow of carrier gas is restored to the chamber and the separated solvent is exhausted from the chamber through a separate outline into a gas chromatographic column.

Abstract: The functions of a gas chromatograph depending on the advancement stage of the analysis can be at least partly controlled by detecting the data relating to the carrier feeding conditions (pressure and/or flow) in a position upstream the injection point of the sample to be analyzed, and by measuring the variations occurring in the conditions after the sample injection. This method is particularly convenient for the analysis of samples with high volumes of eluent, and one of its preferred embodiments foresees the use of a pressure sensor in a point of the carrier feeding duct or, alternatively, of a flow sensor positioned between two points of the feeding duct.

Abstract: This invention concerns a method and a device to perform the adjustment of the cooling temperature of a trap for samples in an apparatus of gas chromatographic analysis. The method according to the invention is characterized in that the cooling fluid flow fed to the trap is adjusted by varying the vacuum caused by a suction device downstream the trap, which is capable of sucking the cooling fluid from a vessel upstream the trap itself.The device according to the invention is characterized in that it comprises a suction means placed downstream the trap and connected by means of a first duct to an end of the trap itself, the other end of the trap being connected, by a second duct, to a vessel containing the refrigerating fluid.

Abstract: The invention concerns a method and an equipment for the simulated distillation, by means of gas chromatography, of petroleum products, capable of characterizing also high boiling products, exceeding C55, over 600.degree. C. TBP. A chromatograph is used with a capillary column having a length less than or equal to 10 m, containing an immobilized non polar polydimethylsilicon gum stationary phase with a film thickness less than or equal to 0.2 .mu.m. The sample is introduced through a non vaporizing direct cold on-column injection and the eluted sample is detected by means of a FID detector. The column oven is operated in temperature programming conditions up to temperatures exceeding 400.degree. (up to 430.degree.-450.degree. C.).