# US 5,347,844 A · Process and device for vaporization injections in equipments for gas chromatographic analysis > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,347,844 A - Document ID: US5347844A - Status: Granted - Kind: A - Application number: 08/004,086 - Filed: 1993-01-13 - Granted: 1994-09-20 - Earliest claimed: 1992-01-14 - Assignees: Fisons Instruments S.p.A. - Inventors: Konrad Grob; Fausto Munari - Web page: https://patentgrep.com/patent/US5347844A ## CPC - G01N 30/12: by evaporation - G01N 2030/127: {PTV evaporation} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## 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. ## Claims ### Claim 1 A process for the injection of liquid samples into a gas chromatograph comprising the steps of: maintaining an injector of said gas chromatograph, said injector including a vaporisation chamber, at a set temperature at least exceeding the boiling point, at operating pressure, of a solvent to be injected and which is sufficiently high to allow for the transfer of a component to be analyzed into a column of said gas chromatograph; opening an exhaust duct from said vaporisation chamber; interrupting a flow of a carrier gas through said vaporisation chamber and into said column; temporarily creating, inside said vaporisation chamber, a cool zone having a temperature substantially equal to said boiling point of said solvent while maintaining said injector at said set temperature; injecting said component to be analyzed into said vaporisation chamber such that at least a part of said component to be analyzed is disposed within said cool zone as a liquid; eliminating said cool zone while maintaining said injector at said set temperature; closing said exhaust duct and restoring said flow of carrier gas to said column; vaporising said component to be analysed; and transporting said vaporised component to be analyzed to said column by means of said flow of carrier gas. ### Claim 2 (depends on 1) The process according to claim 1, wherein said cool zone is formed by the evaporation of the injected solvent. ### Claim 3 (depends on 2) The process of claim 2, wherein said vaporisation chamber further comprises at least one inert packing material of low thermal mass capable of adsorbing said liquid sample when injected. ### Claim 4 (depends on 3) The process of claim 3, wherein said cooling zone is formed within said packing materials. ### Claim 5 (depends on 2) The process of claim 2, wherein said cooling zone is formed by the injection of a liquid sample including said solvent and said component to be analyzed. ### Claim 6 (depends on 2) The process of claim 2, wherein said cooling zone is formed by the injection of a solvent into said vaporisation chamber prior to the introduction of said component to be analyzed. ### Claim 7 (depends on 1) The process according to claim 1 wherein said discharged duct is only partially closed prior to said step of vaporising said component to be analysed. ### Claim 8 (depends on 1) A process according to claim 1, characterised in that the carrier gas feeding is switched off during the solvent evaporation. ### Claim 9 (depends on 1) The process according to claim 1 wherein said set temperature is sufficient to allow the transfer to the column of the most high-boiling component to be analysed. ### Claim 10 (depends on 1) The process according to claim 1, further comprising the step of backflushing the vaporisation chamber after the transfer of the component to be analysed into said column to purge the vaporisation chamber and eliminate sample residue. ### Claim 11 (depends on 1) The process according to claim 1 further comprising the step of applying a vacuum at said exhaust duct. ### Claim 12 (depends on 1) The process of claim 1, further comprising a means for hindering the passage of liquid to said column located in said vaporisation chamber, said means not impeding the flow of vapors from said vaporisation chamber. ### Claim 13 (depends on 12) The process according to claim 12 further comprising the step of manipulating the speed and/or the position of sample introduction into said vaporisation chamber as a function of the position of said obstacles, the position and amount of said packing material and/or the volume of the injected sample and type of solvent. ### Claim 14 (depends on 1) The process of claim 1 wherein said set temperature is substantially the boiling point of at least one component to be analyzed. ### Claim 15 (depends on 14) The method of claim 14 wherein said set temperature is the vaporisation temperature of the least volatile component to be analyzed. ### Claim 16 A process for the injection of liquid samples including a solvent into a gas chromatograph comprising the steps of: maintaining an injector of said gas chromatograph, said injector including a vaporisation chamber, at a set temperature at least exceeding the boiling point, at operating pressure, of said solvent to be injected and which is sufficiently high to allow for the transfer of at least one component to be analyzed within said liquid sample into a column of said gas chromatograph; injecting said liquid sample into said vaporisation chamber in a manner such that at least a portion of said sample creates a cool zone having a temperature substantially equal to the boiling point of said solvent such that at least a portion of said sample remains in the liquid state; vaporizing substantially all of said solvent thereby eliminating said cool zone and discharging said vaporized solvent from said vaporisation chamber through an exhaust duct thereby returning said temperature of said vaporisation chamber to said set temperature; vaporizing said at least one component to be analyzed; and transporting said vaporized component to be analyzed to said column by means of a flow of a carrier gas. ### Claim 17 (depends on 16) The process according to claim 16, wherein said cool zone is formed by the evaporation of the injected solvent. ### Claim 18 (depends on 17) The process of claim 17, wherein said vaporisation chamber further comprises at least one inert packing material of low thermal mass capable of adsorbing said liquid sample when injected. ### Claim 19 (depends on 16) The process of claim 16 wherein said set temperature is substantially the boiling point of at least one component to be analyzed. ### Claim 20 (depends on 19) The method of claim 19 wherein said set temperature is the vaporisation temperature of the least volatile component to be analyzed.