the device shown in fig1 comprises a solvent vaporization chamber 1 , formed in this case by a capillary tube in fused silica with internal diameter of 0 . 32 mm and length 5 - 7 cm . the chamber 1 is connected upstream with a connector 2 , to which is fixed a sample feed line 4a from an interface valve ( see fig2 ) and a transport - gas feed line 4 . downstream , the chamber 1 is connected to a pre - column 5 , for instance a capillary column in fused silica with internal diameter 0 . 53 mm . the pre - column 5 is internally coated with a stationary phase 6 and the end is connected , through a &# 34 ; t - piece &# 34 ; 14 , with a solvent - vapor unloading duct 7 and with the opening of the gc separation column 8 . the unloading duct 7 is fitted with a valve 9 , which allows it to be connected alternatively to an unloading duct 11 with substantially no resistance during the unloading of the vapors , or to a capillary resistance 10 , to unload interrupted vapors . the vaporization chamber 1 is fitted with a means of heating 12 , separate and distinct from the means of heating the pre - column 5 , which is generally the gaschromatograph oven 13 . this configuration mirrors the fact that the chamber 1 is maintained at a temperature very much greater than that of the boiling point of the solvent , generally to at least 200 ° c ., while the pre - column is kept to the lowest temperature which prevents the condensation of the solvent and thus interacts the solvent vapors with the stationary phase 6 ( phase soaking ) so swelling it and increasing the power of retention . inside of the chamber 1 there is a means 3 of stabilizing the evaporation front of the liquid sample entering the vaporization chamber . the temperature of the chamber 1 is such as to prevent the liquid sample from accumulating inside the chamber to the point of escaping and flooding the pre - column 5 . in other words , a means of stabilization serves to avoid a violent and uncontrolled evaporation of the solvent and the so - called &# 34 ; shooting &# 34 ; of the same , i . e . a forward and backward movement of a plug of liquid in chamber 1 , under the effect of the pressure of the vapors of solvent which are being formed . the means 3 comprises a packing of inert material with upper and lower &# 34 ; plugs &# 34 ; in glass wool or a full element inserted in chamber 1 . it has been ascertained -- surprisingly -- that a thread or fiber in metal or a capillary in fused silica , closed at the extremities , treated in such a way to become inactive , eliminates the &# 34 ; shooting &# 34 ; and allows sample feeding with flow - rates more elevated than those otherwise possible . these full tubular elements have external diameters preferably larger than means the internal diameter of the vaporization chamber ; for instance , for a chamber comprising a capillary with internal diameter of 0 . 32 mm an insert is used with external diameter between 0 . 19 and 0 . 29 mm . with regard to the inert packing , this presents the advantage of having a smaller , geometrically simpler surface and is , therefore , a better retainer . in the vaporization chamber there is no means of temporary retention of the compounds e . g . a stationary phase on the inert material or on the thread - like insert , in as far as the sample is vaporized simultaneously with its introduction without substantially discriminating between solvent and compound , as happened in the preceding art . the embodiment shown in fig3 refers to a version of the invention in which a means of retention of the compounds is constituted by a pre - column 5a , deprived of stationary phase , disposed between the vaporization chamber 1 and the capillary column 8 and connected to the latter via the link 14 having the unloading duct 7 . the purpose of the pre - column 5a is to allow recondensation of at least part of the solvent vapors to trap the compounds of interest through the solvent effect . therefore , in this case , the temperature of the pre - column 5a will be regulated to give the desired recondensation of the solvent without at the same time flooding the pre - column 5a . this embodiment could be combined with that of fig1 to give a device which in this case presents , in the following order , the chamber 1 , the pre - column 5a , the pre - column 5 , the duct 7 and the gc capillary column 8 . the fig2 shows an embodiment of an interface for the device according to the invention , i . e . its portion upstream of the vaporization chamber 1 . as can be seen , the duct 4 is fitted with a valve 17 intercepting the transport gas , and the duct 4a is fitted with a valve 18 to control the feeding of liquid sample along the line 19 from a means of supply . generally , the liquid sample arrives from a liquid chromatography apparatus or from a sampler . in more detail , the valve 18 connects the duct 4a directly with the line 19 and a lc apparatus or a sampler , which provide for pushing the sample into the vaporization chamber with the required flow - rate . in this way , the flow of liquid sample is controlled , which is a preferential characteristic of the present invention . there is a resistance 20 provided to reduce the counter - current &# 34 ; backflush &# 34 ; during the analysis . a first separation is effected in the lc ( or hplc ) apparatus . the valve 19 is set in the configuration to dispatch the unloading of the eluent in arrival from the lc column . when the fraction containing the sample to be analyzed comes off the column , it is sent through the line 19 to the valve 18 , which is set to dispatch the fraction directly to the duct 4a and to the vaporization chamber 1 . alternatively , the liquid sample is sent to the chamber 1 in another way , for instance through a sampler . during the introduction of the liquid sample into chamber 1 , the flow of carrier gas is preferably interrupted . the chamber 1 is heated by the means 12 to a temperature superior to that of boiling point of the solvent , and is such as to cause evaporation of the same and of at least part of the compounds as soon as the sample arrives into chamber 1 . the temperature of chamber 1 will generally be at least 200 ° c . but could also reach around 350 ° c ., to evaporate the solvent together with all the compounds . the presence of the file 3 or of the inert packing with plugs in glass wool as described above allows the evaporation front of the sample to stabilize despite the high temperature of the chamber and the high flow - rate of the sample . this stabilization is favoured if the sample is fed into chamber 1 with controlled flow . the non - volatile products remain inside chamber 1 . the vapors thus generated are thereafter made to flow through a pre - column where there is retention of the compounds of present interest in the vapors coming out of chamber 1 . in the case of fig1 the vapors , comprising solvent and compounds , flow from chamber 1 to the pre - column 5 , which is maintained at a lower temperature to that of the chamber 1 . this temperature is sufficient to create the pressure necessary to allow the unloading of the vapors into the atmosphere , and prevent the condensation of the solvent . in other words , this temperature , which could be indicated as &# 34 ; dew point &# 34 ; is such as to allow an interaction of the vapors of solvent with the stationary phase 6 of the pre - column 5 , i . e . such as to provoke a &# 34 ; swelling &# 34 ; of the stationary phase -- the so - called &# 34 ; phase soaking &# 34 ;-- by part of the solvent vapors and thus increase the retention power for the compounds of interest in this way , on the part of the stationary phase . the fig5 shows the chromatogram of the analysis of 600 μl of pentane containing a compound of c10 - c20 alkanes , injected with flow - rate of 400 μl / min and transferred , once vaporized , to a pre - column coated with stationary phase , maintained at 48 ° c . to optimize the &# 34 ; phase soaking .&# 34 ; in the case of fig3 the vapors flow from the pre - column 5a , which is maintained at such a temperature as to guarantee the recondensation of at least part of the solvent vapors and their subsequent evaporation for the unloading from the duct 11 . according to this technique , a flow of transport gas is preferably fed in this phase to the pre - column 5a to promote the evaporation of the solvent . two advantages are derived : there is partial recondensation of the solvent , avoiding the use of very long pre - columns , and if the vapors are diluted , so the temperature at which the pre - column is maintained is reduced . this variation , i . e . the recondensation of the vapors in a retention gap , is adopted when the sample contains volatile compounds that would not be sufficiently retained by the stationary phase of the pre - column 5 . as mentioned above , the presence of liquid solvent allows , through the so - called solvent effect ( solvent trapping ), the trapping of the more volatile compounds . during the solvent evaporation phase and the passage of its vapors through the pre - column 5 or 5a , the valve 9 is set to connect the duct 7 with the unloading duct 11 , and the vapors leaving the pre - column 2 flow therefore through the ducts 7 and 11 . once the phase of unloading the solvent has ended ( or before , if desired in operation of the formalities of control of the functions of the gaschromatograph ) the valve 9 is set to the resistance 10 to have a flow of drainage and , if fact is not already stayed , will feed the carrier gas to the vaporization chamber again . the precolumns 5 , or 5a , are therefore heated to carry the compounds to the separation column 8 . it is possible to effect the feeding of the sample to the chamber 1 in other ways , for instance through a loop with carrier gas , but the forms described above ( controlled flow ) have been particularly advantageous in that they have allowed fractions to be transferred with larger volumes and to identify and analyze even the more volatile compounds . a solution has been prepared in pentane of a product with a mineral oil base consisting of c20 - c26 isoalkanes of the type used in the food industry as a separator . the concentration of the mineral oil was 0 . 5 μg / ml , and that of the internal standard ( n - c13 ) was equal to 0 . 03 μg / ml ( i . e . 30 times smaller than possible with traditional processes ). 400 ul of the solution was injected into a device comprising a vaporization chamber with insert in metallic thread and a pre - column of 2 m coated with ps 255 . the temperature of the vaporization chamber was of 350 ° c . and that of the pre - column of 50 ° c . during the transfer of the injected sample ; there followed a programmed to 15 ° c ./ min . the resultant chromatogram , which corresponds to a concentration of 1 . 5 ug of mineral oil per mg of feed fat is shown in fig4 .