CN114965737A

CN114965737A - Thermal cracking chromatographic analysis and detection method and device

Info

Publication number: CN114965737A
Application number: CN202210387843.6A
Authority: CN
Inventors: 刘海英; 刘钟
Original assignee: Beijing Jsdy Analytical Instruments R & D Center; Beijing Jiafen Analytical Instrument Technology Co ltd
Current assignee: Beijing Jsdy Analytical Instruments R & D Center; Beijing Jiafen Analytical Instrument Technology Co ltd
Priority date: 2022-04-14
Filing date: 2022-04-14
Publication date: 2022-08-30
Anticipated expiration: 2042-04-14
Also published as: CN114965737B

Abstract

The invention relates to a thermal cracking chromatographic analysis detection method, which comprises the following steps: the invention improves the chromatographic analysis method, saves the detection steps, can realize sample injection of solid and liquid, realizes non-puncture type wide sample injection, avoids the problem that the sample is easy to block and pollute in the puncture type sample injection, improves the structure of a sample injector, is a sample injection device formed by communicating a thermal cracker and the sample injector, shortens the whole pipeline length of the detection device, saves the experimental space, and ensures that the peak appearance graph is more obvious, the peak area is large, the image is clear and the observation is convenient by setting the sample injection time and the cracking time through the change of the original method.

Description

Thermal cracking chromatographic analysis detection method and device

The technical field is as follows:

the invention relates to an analytical detection method, in particular to a thermal cracking chromatographic analytical detection method and a thermal cracking chromatographic analytical detection device.

Background

The gas chromatograph is a universal instrument, has wide application fields, can be used in a plurality of fields such as indoor environment detection, food research, petrochemical industry and the like, develops thermal cracking gas chromatography technology on thermal cracking technology and gas chromatography technology, and is effectively applied in the fields of petrochemical industry, organic chemistry, biomedicine, polymer chemistry, geological exploration, environmental protection and the like at present. When the evaporable components in the solid are analyzed, a sample cannot be directly injected, a complex sample pretreatment process is generally required, and waste liquid is often generated in the treatment process and has no good influence on operators and the environment, so that a thermal cracking technology is developed for gas chromatography analysis. The thermal cracking sample injection technology is that under the instant high-temperature heating, high boiling point organic matter in a solid sample to be detected is cracked and analyzed instantly, becomes gas which can be used for gas chromatography analysis, and enters a gas chromatograph for analysis and identification.

Disclosure of Invention

In order to solve the technical problem, the invention discloses a thermal cracking chromatographic analysis detection method, which comprises the following steps:

step A, detection preparation

Taking a sample for later use, introducing carrier gas into the chromatographic column when the thermal cracking chromatographic detector is in a preparation state, and introducing the sample into a sample introduction device;

step B, heating desorption

Heating and desorbing the sample subjected to sample introduction in the step A in a sample introduction device to obtain a gas to be detected;

step C, sample injection purging

Continuously introducing carrier gas into the sample injection device, blowing and injecting the gas to be detected in the step B into the chromatographic column, separating each component of the gas to be detected in the chromatographic column, and detecting the gas to be detected in the detector to generate an electric signal;

step D, data analysis

C, the component electric signals of the tested sample obtained in the step C enter a chromatographic workstation through a signal amplifier, the chromatographic workstation processes and calculates the information of the detected signals, and the detection result is displayed through a connecting display;

step E, cleaning

And D, discharging residual gas remained in the sample introduction device in the step C.

Specifically, the sample introduction of the sample introduction device in the step A adopts a non-puncture type sample introduction.

Specifically, the sampling device in step A comprises: the thermal cracker and the injector are communicated.

Specifically, the thermal cracker in the step a includes: sampling pipe one end intercommunication sealing connecting piece, sampling pipe surface encircle and set up the heating member, and the sampling pipe other end intercommunication injector forms the space that is used for heating the schizolysis sample, carries out the gas tightness gas circuit intercommunication through the pipeline between sealing connecting piece and carrier gas and the blowback export.

Specifically, a sealing joint, comprising: the communicating piece is internally provided with a through hole, two ends of the communicating piece are connected with an upper nut and a lower nut in a sealing way, the upper nut is provided with the through hole which is communicated with a gas path formed by a carrier gas through a pipeline, the lower nut is provided with a communicating hole which is communicated with a sampling pipe, the communicating piece body is also provided with another through hole, and the two through holes on the communicating piece are communicated to form a passage.

Specifically, a sealing joint, comprising: the fastener has the through-hole, and with sampling pipe intercommunication, and the two sealing connection, fastener and sealing nut sealing connection, still be provided with two through-holes on the fastener body, and communicate with each other with the fastener through-hole, form and carry out the gas tightness gas circuit intercommunication through the pipeline between carrier gas and the blowback export.

Specifically, in the step A, the pipelines are a gas pipe I and a hose II, the sealing connecting piece is provided with a communicating hole, and the gas pipe I and the hose II are communicated with the space of the thermal cracking sample through a carrier gas and back flushing outlet.

Specifically, the injector in step a includes: one end of the sample injection pipe is provided with a fixedly connected sample injection device cap, the sample injection device cap is provided with a through hole which is communicated with the sampling pipe in the thermal cracker in an air tightness manner to form a gas passage, and an air tightness passage is arranged between the sample injection device cap and the thermal cracker.

In the step A, a carrier gas outlet and a shunt outlet are arranged on the sample injection tube body, one end of the sample injection tube body is communicated with the chromatographic column to form a gas passage, the carrier gas outlet is communicated with the carrier gas, and the shunt outlet is connected with a hose and is communicated with the outside atmosphere.

Specifically, the air pipe I is an inert pipe.

Specifically, the chromatographic column in the step C is a nonpolar column.

Specifically, in the step A, a gas passage is formed by the sample introduction device and the chromatographic column in sequence by adjusting the switching valve.

Specifically, in the step C, by adjusting the switching valve, the carrier gas is introduced into the chromatographic column through the sample injection device, and the chromatographic column is communicated with the detector, so that a gas passage is formed by the sample injection device, the chromatographic column and the detector in sequence.

Further, the analysis and detection method further comprises:

f, back blowing the standard sample

And adjusting a conversion valve to realize that a gas passage is formed from the sample injection device and the back flushing outlet to the external atmosphere in sequence, wherein the back flushing time is 2-4 minutes.

Specifically, the switching valve in the step a is a third on/off valve.

Specifically, in the step C, the switching valve is adjusted to close the third switch valve and open the second switch valve.

Specifically, in the step E, the switching valve is adjusted to close the second switch valve and open the first switch valve and the third switch valve.

Specifically, a thermal cracking chromatographic detector capable of realizing a thermal cracking chromatographic analysis detection method comprises: the sample injection device is respectively communicated with the carrier gas and the chromatographic column, a gas passage is formed among the carrier gas, the chromatographic instrument and the detector, the signal amplifier, the chromatographic workstation and the computer are electrically or signal connected.

Further, a thermal cracking chromatographic detector capable of realizing the thermal cracking chromatographic analysis detection method, further comprising: the sample injection device and the carrier gas form an airtight passage through a pipeline, and a pressure sensor is arranged on the pipeline.

Furthermore, the sample injection device comprises a thermal cracker and a sample injector which are communicated, the thermal cracker comprises a sealing connecting piece, a communicating hole is formed in the sealing connecting piece, the communicating hole is communicated with a gas pipe I and is communicated with carrier gas, an adjustable second switch valve is arranged on the gas pipe I and is used for opening or closing a gas circuit, the sample injector is communicated with a chromatographic column to form an air tightness gas circuit, the chromatographic column is communicated with a detector, and a gas channel for detecting a sample is formed by opening the second switch valve.

The sample injection device comprises a thermal cracker and a sample injection device which are communicated, the sample injection device comprises a sample injection pipe, the sample injection pipe is provided with a carrier gas outlet which is communicated with carrier gas through a hose III, a branch outlet which is communicated with the outside atmosphere through a hose, an adjustable third switch valve is arranged on a gas pipe III and used for opening or closing a gas circuit, the thermal cracker comprises a sampling pipe and a sealing connecting piece, a communicating hole is arranged on the sealing connecting piece and communicated with the hose II, an adjustable first switch valve is arranged on the hose II and used for opening or closing the gas circuit and communicated with the outside atmosphere to form a back-blowing outlet, and gas discharge is realized by opening a gas passage formed by the first switch valve and the third switch valve.

Further, a thermal cracking chromatographic detector capable of realizing the thermal cracking chromatographic analysis detection method, further comprising: and a back-blowing flow sensor is also arranged on the hose II and used for monitoring the back-blowing gas flow, and a flow dividing valve and a flow dividing flow sensor are arranged on the flow dividing outlet hose on the injector and used for monitoring the flow dividing flow.

Further, a thermal cracking chromatographic detector capable of realizing the thermal cracking chromatographic analysis detection method, further comprising: the chromatographic column is respectively communicated with the sample injection device and the detector, a gas passage is formed between the sample injection device and the detector, a communicating hole is formed in a sealing connecting piece in the pyrolysis device and is connected with a gas pipe I, a carrier gas outlet is formed in the sample injection device of the sample injection device and is connected with a hose III, the gas pipe I and the gas pipe III are communicated with a carrier gas through a valve, the communicating hole of the sealing connecting piece is communicated with a hose II to form a cleaning outlet, a first switch valve is arranged on the gas pipe I, a second switch valve is arranged on the gas pipe III, a third switch valve is arranged on the hose II and is used for controlling a gas circuit, the detector is connected with a signal amplifier, a chromatographic workstation and a computer, processing and calculation are carried out through the chromatographic workstation, and a graph detection result is displayed by the computer.

Advantageous effects

The invention provides a thermal cracking chromatographic analysis and detection method, which has the following advantages and effects:

1. the invention improves the chromatographic analysis method, saves the detection steps, can realize the sample injection of solid and liquid, realizes the non-puncture type wide sample injection, and avoids the problems of easy blockage and easy pollution of the sample in the puncture type sample injection.

2. The invention improves the structure of the sample injector, and the thermal cracker is communicated with the sample injector to form a sample injection device, thereby shortening the overall pipeline length of the detection equipment and saving the experimental space.

3. The chromatographic column is modified into a nonpolar column, so that the position of a second sample peak in a detection image is clear, and the observation is convenient.

4. By setting the sample introduction time and the cracking time, the invention has the advantages of more obvious peak appearance graph, large peak area, clear image and convenient observation.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of a sample injection device according to the present invention;

FIG. 3 is a schematic view of a sample injection device according to the present invention;

FIG. 4 is a schematic view of a sample injection device according to the present invention;

FIG. 5 is a graph showing the results of the test using the inert tube according to the present invention;

FIG. 6 is a graph showing the results of the test using the inlet hose of the present invention;

FIG. 7 is a graph showing the results of detection using a nonpolar capillary chromatography column according to the present invention;

FIG. 8 is a graph showing the results of the detection using a weakly polar capillary chromatography column according to the present invention.

Legend: 2. a sample introduction device; 21. a thermal cracker; 211. a sampling tube; 212. a sealing connection; 2121. a communicating member; 2122. screwing a nut; 2123. a lower nut; 2126. a fastener; 2127. a sealing nut; 213. a heating body; 22. a sample injector; 221. injecting a sample tube; 222. a syringe cap; 223. a carrier gas outlet; 224. a shunt outlet; 4. a first on-off valve; 5. a second on-off valve; 6. a third on-off valve; 7. a chromatographic column; 8. a trachea I; 9. air pipes III, 10 and a hose II; 11. a detector; 12. a signal amplifier; 13. a chromatography workstation; 14. a display; 15. a blowback outlet; 16. a pressure sensor; 17. a flow sensor; 18. a shunt sensor; 19. a flow divider valve.

Detailed Description

The present invention is further illustrated by the following examples, but is not limited to the details of the description.

A thermal cracking chromatographic analysis detection method comprises the following steps:

step A, detection preparation

Weighing 1mg of solid sample for later use, recording the actual weighing amount, keeping the carrier gas in the thermal cracking chromatographic detector unblocked when the thermal cracking chromatographic detector enters a preparation state, enabling the carrier gas to enter a chromatographic column 7 in the preparation state, injecting the sample into a sample injection device, opening the sample injection device when injecting the sample, placing the sample into the sample injection device, and closing the sample injection device after placing the sample;

step B, heating desorption

Heating and desorbing the sample subjected to sample injection in the step A in a sample injection device at the heating temperature of 250-350 ℃, the heating and desorbing time of 20-40 seconds, the heating and desorbing temperature is low, the sample is insufficiently desorbed, the obtained gas to be detected has low concentration, and the peak area of the detected image is small; the heating desorption temperature is too high, ghost peaks are easy to appear, the detection result is influenced, the heating desorption time is too long or too short, the peak shape of the detection result graph is not sharp, the area of the peak graph is small, and the detection graph effect is not good.

Step C, sample injection purging

Continuously introducing carrier gas into the sample introduction device, introducing the gas to be detected in the step B into the chromatographic column 7, setting the sample introduction time to be 1 minute, 30 seconds to 3 minutes, and obtaining the electric signals of all components by the detector 11 according to the concentration of the components in the gas to be detected; the detector 11 may be a hydrogen flame ion detector, and the control of the sample injection time can make the peak shape sharp and the peak area large, and the data in the following examples and comparative examples can show the influence of the control of the sample injection time on the peak area.

Step D, data analysis

And C, enabling the electric signals of the components of the sample to be detected obtained in the step C to enter a chromatographic workstation through a signal amplifier, processing and calculating detection signal information by the chromatographic workstation, displaying a detection result through a connection display, electrically connecting a detector 11 with the signal amplifier, receiving and amplifying the signals by the signal amplifier, sending the amplified signals to the chromatographic workstation, obtaining signal calculation and processing by the chromatographic workstation, enabling the detected signal data to form a detection peak value graph on the display.

Step E, cleaning

And C, discharging residual gas remained in the sample injection device in the step C, setting the cleaning time to be 4-6 minutes, mostly repeating experiments in chromatographic experiments, cleaning operation for ensuring cleanness and reuse of the pipeline, reducing sample residue in the pipeline by the cleaning operation, avoiding the problems of pipeline blockage and pollution and the like of the sample in the pipeline, and better protecting the pipeline.

In the step A, the sample introduction of the sample introduction device adopts a non-puncture type sample introduction mode, the sample introduction device is opened during sample introduction, the sample introduction is directly carried out in the sample introduction device, solid and liquid samples can be selected, a puncture type sample introduction mode different from the conventional puncture type sample introduction mode is required, a puncture spacer is required to be adopted to seal a sample introduction port, and a needle is required to be connected, in order to ensure the sample introduction effect, a needle head of a sample introduction needle is generally thinner, the needle head can be easily blocked after long-time use, the sample introduction spacer is mainly made of silicon rubber materials, when the puncture type sample introduction is adopted by the device in the step A, under the condition that other conditions are not changed, the sample introduction spacer inevitably contains some residual solvents and/or low molecular oligomers, in addition, due to the influence of high temperature in a thermal cracking chamber, the silicon rubber can be partially degraded, and if the residual solvents and degradation products enter a chromatogram, ghost peaks can possibly occur, affecting the detection result.

As shown in fig. 2, the sample injection device 2 in step a includes: the thermal cracker 21 and the injector 22 are communicated with each other, and the thermal cracker 21 includes: one end of the sampling tube 211 is communicated with the sealing connecting piece 212, the outer surface of the sampling tube 211 is provided with the heating body 213 in a surrounding way, the other end of the sampling tube 211 is communicated with the sample injector 22 to form a space for heating a cracking sample, the sealing connecting piece 212 is communicated with the carrier gas and the back blowing outlet through pipelines to form an air tightness gas circuit, the sealing connecting piece 212 is provided with a communication hole, the gas pipe I8 is communicated with the sample space of the thermal cracker through one communication hole, the hose II 10 is communicated with the sample space of the thermal cracker through another communication hole, the heating body 213 is a heating device and can be heated by adopting an electric heating wire, the constant temperature precision is high, the cracking balance temperature is continuously adjustable, and the control and the measurement are easy. The injector 22 includes: one end of the sample injection pipe 221 is provided with a fixedly connected sample injection cap 222, the sample injection cap 222 is provided with a through hole which is communicated with the sampling pipe 211 in the thermal cracker 21 in an airtight manner to form a gas passage, a sealing element is arranged between the sample injection cap 222 and the thermal cracker 21 to realize sealing, the formed passage is the airtight passage, a carrier gas outlet and a shunt outlet are arranged on the pipe body of the sample injection pipe 221, one end of the carrier gas outlet is communicated with the chromatographic column 7 to form the gas passage, the carrier gas outlet is communicated with the carrier gas, the shunt outlet is connected with a hose and is communicated with the external atmosphere, a controller is arranged in the thermal cracker 21, the cracking temperature can be controlled, the pipeline distance between the thermal cracker 21 and the sample injector 22 is shortened by the sample injector 2 formed by connecting the thermal cracker 21 and the sample injector 22, the device is different from the prior thermal cracker which is used as an independent device and needs an independent pipeline and a controller, and the detection space can be reduced by the pipeline of the sample injector as a whole due to the connection structure of the thermal cracker 21 and the sample injector 22.

As shown in fig. 3, which is a schematic diagram of a structure of the sealing connector 212, the sealing connector 212 includes: the connecting piece 2121 is internally provided with a through hole, two ends of the connecting piece are connected with an upper nut 2122 and a lower nut 2123 in a sealing manner, the upper nut 2122 is provided with a through hole which is communicated with a carrier gas through a pipeline to form a gas path, the lower nut 2123 is provided with a communicating hole which is communicated with the sampling tube 211, the body of the connecting piece 2121 is also provided with another through hole, the two through holes on the connecting piece 2121 are communicated to form a passage, a sealing element is arranged at the joint of the connecting piece 2121 and the upper nut 2122 and the lower nut 2123, the sealing element is a rubber sealing ring or a rubber sealing plug and the like, the gas path is ensured to be closed, the phenomena of gas leakage and the like do not exist, the two through holes on the connecting piece 2121 are communicated and are mutually and axially vertical, the upper nut 2122 on the sealing connecting piece 212 is opened during sample injection, a sample can directly enter the sampling tube 211 to be heated, the sample can be rapidly desorbed, the experimental operation is convenient, and the pipeline path during the sample injection is shortened.

As shown in fig. 4, which is another structural schematic diagram of the sealing connector 212, the sealing connector 212 includes: fastener 2126 has the through-hole, and communicates with sampling pipe 211, and the two sealing connection, fastener 2126 and sealing nut 2127 sealing connection, fastener 2126 still are provided with two through-holes on the body, and communicate with each other with fastener 2126 through-hole, form and carry out gas tightness gas circuit intercommunication through the pipeline between carrier gas and the blowback export 15, fastener 2124 is equipped with the sealing washer with sampling pipe 211 intercommunication department, and is equipped with the sealed pad with sealing nut 2125 junction, guarantees the gas circuit leakproofness, the phenomenon such as gas leakage can not appear leaking.

The gas pipe i 8 in the thermal cracking chromatography detection analysis method is an inert pipe, and as shown in fig. 5, the image detection result using the inert pipe is shown, the solvent peak on the left side in the figure is sharp and does not trail, and as shown in fig. 6, the image detection result using the inlet hose is shown, and the solvent peak on the left side in the figure has a large tailing phenomenon, so that the result is inconvenient to observe.

The chromatographic column 7 in the thermal cracking chromatographic detection analysis method is a nonpolar capillary chromatographic column, as shown in an image detection result shown in fig. 7, a detection graph when the nonpolar capillary chromatographic column is used, the image detection result shown in fig. 8 is compared, the detection image when the weak polarity capillary chromatographic column is used, and the comparison of the two images can clearly show that when the weak polarity capillary chromatographic column is used, the obvious impurity peak which can shield the second sample peak can be clearly seen in front of the second sample peak image, the display of the detection image can be influenced, when the nonpolar capillary chromatographic column is used, the impurity peak is adjusted to the back of the second sample peak, the detection image cannot be shielded, and the image detection result can be clearly displayed.

In the step A, a carrier gas outlet formed on the injection pipe 221 sequentially from the sample injection device 2 is formed by opening the third switch valve 6 in the purging process, so that the carrier gas is led to the chromatographic column 7, the gas circulation in the chromatographic column 7 of the thermal cracking chromatographic detector is ensured, and the conditions of damage and the like of the chromatographic column 7 caused by heating are avoided.

In the step C, by closing the third switch valve 6 and opening the second switch valve 5 in the chromatographic detection, the carrier gas is communicated with the chromatographic column 7 through the injector 22 in the sample injection device 2, the detection gas enters the detector 11 after passing through the chromatographic column 7, and the chromatographic column realizes that a gas passage is formed by the sample injection device 2, the chromatographic column 7 and the detector 11 in sequence.

The color cracking chromatographic analysis detection method also comprises the following steps:

f, back blowing of the standard sample

And adjusting the change-over valve to close the second switch valve 5 and open the first switch valve 4 and the third switch valve 6 to realize that a gas passage is formed to the outside atmosphere by the sample injection device 2 and the back flushing outlet 15 in sequence, wherein the back flushing time is 2-4 minutes, when the sample is a liquid standard sample, the solution needs to be back flushed, and the influence of the solvent on the inspection result is discharged.

A thermal cracking chromatographic detector capable of realizing a thermal cracking chromatographic analysis detection method comprises the following steps: sampling device 2 communicates carrier gas and chromatographic column 7 respectively, forms the gas passage between the three for form the gas passage when guaranteeing to detect, chromatograph 7 and the 11 intercommunication formation gas passage of detector for detect the sample that is surveyed, through signal connection between detector 11, signal amplifier, the chromatographic work station and the computer, be used for showing the testing result, the carrier gas is nitrogen gas, sampling device 2 and carrier gas pass through the pipeline and form the gas tightness passageway, are equipped with pressure sensor 16 on the pipeline, during the use, the carrier gas lets in into in the chromatographic column 7 after sampling device 2, detects by detector 11 after the chromatographic column 7 separation sample, behind signal amplifier 12 and the 13 processing data of chromatographic work station, shows the image on display 14.

A sample injection device 2 comprises a thermal cracker 21 and a sample injector 22 which are communicated, the sample injector 22 comprises a sample injection pipe 221, the sample injection pipe 221 is provided with a carrier gas outlet which is communicated with carrier gas through a gas pipe III 9, the gas pipe III 9 is provided with an adjustable third switch valve 6, the thermal cracker 21 is used for opening or closing the gas circuit, and comprises a sampling pipe 211 and a sealing connecting piece 212, wherein the sealing connecting piece 212 is provided with a through hole which is communicated with a hose II 10, the hose II 10 is provided with an adjustable first switch valve 4, used for opening or closing the gas circuit and communicated with the outside atmosphere to form a back-blowing outlet, realizes gas discharge by opening a gas passage formed by the first switch valve 4 and the third switch valve 6, a back-blowing flow sensor 17 is also arranged on the hose II 10, the flow-dividing device is used for monitoring the flow of back-blowing gas, and a flow-dividing valve 19 and a flow-dividing flow sensor 18 are arranged on a flow-dividing outlet hose on the injector 22.

A sample injection device 2 comprises a thermal cracker 21 and a sample injector 22 which are communicated, the thermal cracker 21 comprises a sealing connecting piece 212, a communicating hole is formed in the sealing connecting piece and communicated with a gas pipe I8 and a carrier gas, an adjustable second switch valve 5 is arranged on the gas pipe I8 and used for opening or closing a gas circuit, the sample injector 22 is communicated with a chromatographic column 7 to form a gas tightness gas circuit, the chromatographic column 7 is communicated with a detector 11, and a gas channel for detecting a sample is formed by opening the second switch valve 5.

As shown in fig. 1, a thermal cracking chromatographic detector capable of implementing the thermal cracking chromatographic analysis detection method further includes: the chromatographic column 7 is respectively communicated with the sample injection device 2 and the detector 11 to form a gas passage, a communicating hole is arranged on a sealing connecting piece 212 in a pyrolysis device 21 in the sample injection device 2 to be connected with a gas pipe I8, a carrier gas outlet is arranged on a sample injection pipe 221 in a sample injector 22 in the sample injection device 2 to be connected with a hose III 9, a branch outlet 224 is arranged on the sample injection pipe 221 and is connected with the hose to form a gas-tight gas passage, a branch valve 19 and a branch flow sensor 18 are arranged on the hose, the gas pipe I8 and the hose III 9 are communicated with the carrier gas through a valve, a pressure sensor 16 is arranged between the valve and the carrier gas, the communicating hole of the sealing connecting piece 212 is communicated with a hose II 10 to form a back-blowing outlet, a second switch valve 5 is arranged on the gas pipe I8, a third switch valve 6 is arranged on the gas pipe III 9, a first switch valve 4 and a flow sensor 17 are arranged on the hose II 10 to monitor the back-blowing flow, the detector 11 is electrically connected with the signal amplifier, the chromatographic workstation and the computer, the processing and calculation are carried out by the chromatographic workstation, the graph detection result is displayed by the computer, when in use, the third switch valve 6 is opened, the carrier gas is firstly sequentially introduced into the sample injector 22 and the chromatographic column 7 of the sample injection device 2 through the air pipe III 9, the sealing connecting piece is opened during sample injection, the sample is put into the sample injection device 2, the sample is heated and desorbed in the sample injection device 2, after desorption is completed, the third switch valve 6 is closed, the second switch valve 5 is opened, the carrier gas is sequentially introduced into the sample injection device 2, the chromatographic column 7 and the detector 11 through the air pipe I8, the chromatographic detection is completed, the signal is amplified through the signal amplifier 12, the data is received and processed by the chromatographic workstation 13, the detection image is displayed on the display 14, the second switch valve 5 is closed, the first switch valve 4 and the third switch valve 6 are opened, the carrier gas passes through trachea III 9 in proper order, sampling device 2, arrives the blowback export, washs the operation, accomplishes above-mentioned chromatogram detection method, the thermal cracking chromatogram detector of this application has combined the function of thermal cracking appearance and chromatograph, through improving injector structure, makes sampling device can realize the appearance of non-puncture type sample introduction, has avoided easy stifled easy contaminated condition that appears when puncture type advances the appearance in the equipment in the past, and the structure of integration has shortened the whole pipeline length of check out test set, has saved test space.

To fully demonstrate the assay method of the present application, the present application provides data for examples and comparative examples:

example 1

Performing the operations as described above in the experimental steps a to E;

wherein the heating temperature in the step B is set to 300 ℃, and the desorption time is set to 30 seconds;

wherein the purging sample introduction time in the step C is 2 minutes and 20 seconds;

and (5) after the sample injection time is over, cleaning is carried out, the cleaning time is set to be 5 minutes, and the detection is finished.

Example 2

As described above in the detection steps a to E, when the selected conditions are different from those in embodiment 1:

wherein the heating temperature in the step B is set to be 250 ℃, and the desorption time is set to be 20 seconds;

wherein the purging sample introduction time in the step C is set to be 1 minute and 30 seconds;

and (5) after the sample introduction is finished, cleaning is carried out, the cleaning time is set to be 4 minutes, and the detection is finished.

Example 3

wherein the heating temperature in the step B is set to 350 ℃, and the desorption time is set to 40 seconds;

wherein, the purging sample injection time in the step C is set to be 3 minutes;

and (5) after sample introduction, cleaning is carried out, the cleaning time is set to be 6 minutes, and detection is finished.

Comparative example 1

The procedure was carried out as described above for detection of steps A to E, and the procedure was the same as in example 1, except that the heating desorption time in step B was set to 15 seconds and the purge injection time in step C was set to 1 minute.

Comparative example 2

The procedure from detection step A to detection step F was carried out as described above, and the procedure was the same as in example 1, except that the heating desorption time in step B of this comparative example was set to 2 minutes, and the purge injection time in step C was set to 3 minutes and 30 seconds.

Comparative example 3

The procedure from step A to step F was examined as described above, and the procedure was the same as in example 2 except that the heating temperature was set to 450 ℃ in step B of this comparative example.

Comparative example 4

The procedure was carried out by examining step A to step F as described above, and the procedure was the same as in example 2 except that the heating temperature was set to 220 ℃ in step B of this comparative example.

TABLE 1

As can be seen from the data in Table 1, the heating temperature, the heating desorption time and the sample injection purging time all have important influences on the chromatographic detection result. As can be seen from the examples 1 and the comparative examples 1-2, in the chromatographic detection process, the heating desorption time and the purging sample injection time have great influence on the detection result, when the heating desorption time is not within 20 seconds to 40 seconds and the purging sample injection time is not within 1 minute to 30 seconds to 3 minutes, the peak area of the obtained detection result is small and is not easy to observe, and the areas of the latter two peaks are seriously reduced compared with the areas of the former two peaks, so that the heating desorption time and the purging sample injection time within the range of the application can enable the peak area to be large, the detection result is clear and easy to observe, and the heating temperature also has great influence on the chromatographic detection result, for example, when the heating temperature is more than 200 ℃ or less than 250 ℃ or more than 350 ℃, the peak area in the chromatographic detection result is small, and the areas of the latter two peaks are seriously reduced compared with the areas of the former two peaks, the invention is not easy to observe, the peak area of the chromatographic detection result is large by setting the heating temperature, the heating desorption time and the purging sample injection time, and the areas of the four peaks are basically consistent, thus being easy to observe the detection result.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. Not all embodiments are exhaustive. All obvious changes and modifications which are obvious to the technical scheme of the invention are covered by the protection scope of the invention.

Claims

1. A thermal cracking chromatographic analysis detection method is characterized in that: the detection method comprises the following steps:

step A, detection preparation

A sample is reserved, the thermal cracking chromatographic detector enters a preparation state, carrier gas is introduced into the chromatographic column (7), and the sample is injected into the sample injection device (2);

step B, heating desorption

Heating and desorbing the sample injected in the step A in a sample injection device (2) to obtain a gas to be detected; step C, sample injection purging

Continuously introducing carrier gas into the sample introduction device (2), blowing and introducing the gas to be detected in the step B into the chromatographic column (7), separating components of the gas to be detected in the chromatographic column (7), and detecting in the detector (11) to generate an electric signal;

step D, data analysis

C, the detection data obtained in the step C enter a chromatographic workstation (13) through a signal amplifier (12), the chromatographic workstation (13) processes and calculates detection signal information, and a connection display (14) displays a detection result; step E, cleaning

And C, discharging residual gas remained in the sample injection device in the step C.

2. A thermal cracking chromatographic assay method according to claim 1, characterized in that: and in the step A, the sample introduction of the sample introduction device adopts a non-puncture type sample introduction.

3. A thermal cracking chromatographic assay method according to claim 1, characterized in that: step A, the sample introduction device (2) comprises: the thermal cracker (21) and the injector (22) are communicated with each other.

4. A thermal cracking chromatographic assay method according to claim 3, characterized in that: the thermal cracker (21) in step A comprises: sampling tube (211) one end intercommunication sealing connecting piece (212), sampling tube (211) surface encircles and sets up heating body (213), and sampling tube (211) other end intercommunication injector (22) form the space that is used for heating the schizolysis sample, carry out gas tightness gas circuit intercommunication through the pipeline between sealing connecting piece (212) and carrier gas and blowback export (15).

5. A thermal cracking chromatographic assay method according to claim 4, wherein the seal connection member (212) comprises: establish the through-hole in communicating piece (2121), both ends are sealed to be connected and are gone up nut (2122) and lower nut (2123), go up nut (2122) and be equipped with the through-hole and pass through the pipeline with the carrier gas and form the gas circuit intercommunication, nut (2123) are equipped with the intercommunicating pore and sample tube (211) intercommunication down, and still are provided with another through-hole on the communicating piece (2121) piece body, and two through-holes on communicating piece (2121) communicate, form the passageway.

6. A thermal cracking chromatographic assay method according to claim 4, wherein the seal connection member (212) comprises: the fastener (2126) is provided with a through hole and is communicated with the sampling pipe (211) and is in sealing connection with the sampling pipe, the fastener (2126) is in sealing connection with the sealing nut (2127), two through holes are further formed in the body of the fastener (2126) and are communicated with the through hole of the fastener (2126), and the air-tight air path communication between the fastener and the carrier gas and back flushing outlet (15) is achieved through a pipeline.

7. The thermal cracking chromatographic assay detection method according to claim 4, characterized in that: and in the step A, pipelines are an air pipe I (8) and a hose II (10), a communicating hole is formed in the sealing connecting piece (212), and the air pipe I (8) and the hose II (10) are communicated with a thermal cracking sample space through a carrier gas and back flushing outlet (15).

8. A thermal cracking chromatographic detection method according to claim 3, characterized in that: step A the injector (22) comprises: one end of the sample injection pipe (221) is provided with a fixedly connected sample injection cap (222), the sample injection cap (222) is provided with a through hole which is communicated with the sampling pipe (211) in the thermal cracker (21) in an airtight mode to form a gas passage, and an airtight passage is arranged between the sample injection cap (222) and the thermal cracker (21).

9. A thermal cracking chromatographic assay method according to claim 8, wherein: in the step A, a carrier gas outlet (223) and a branch outlet (224) are arranged on the body of the sample injection pipe (221), one end of the carrier gas outlet is communicated with the chromatographic column (7) to form a gas passage, the carrier gas outlet is communicated with the carrier gas, and the branch outlet (224) is connected with a hose and is communicated with the outside atmosphere.

10. A thermal cracking chromatographic assay method according to claim 7, wherein: the air pipe I (8) is an inert pipe.

11. A thermal cracking chromatographic assay method according to claim 1, characterized in that: the chromatographic column (7) in the step C is a nonpolar column.

12. A thermal cracking chromatographic assay method according to claim 1, characterized in that: in the step A, a gas passage is formed by the sample introduction device (2) and the chromatographic column (7) in sequence by adjusting the switching valve.

13. A thermal cracking chromatographic assay method according to claim 1, characterized in that: in the step C, by adjusting the switching valve, the carrier gas is introduced into the chromatographic column (7) through the sample injection device (2), and the chromatographic column (7) is communicated with the detector (11), so that a gas passage is formed by the sample injection device (2), the chromatographic column (7) and the detector (11) in sequence.

14. A thermal cracking chromatographic assay method according to claim 1, wherein the analytical assay method further comprises:

f, back blowing of the standard sample

And a change-over valve is adjusted to realize that a gas passage is formed to the external atmosphere by the sample injection device (2) and the back flushing outlet (15) in sequence, and the back flushing time is 2-4 minutes.

15. A thermal cracking chromatographic assay method according to claim 12, wherein: the switching valve in the step A is a third switch valve (6).

16. A thermal cracking chromatographic assay method according to claim 13, wherein: and C, adjusting the switching valve to close the third switch valve (6) and open the second switch valve (5).

17. The thermal cracking chromatography detection method according to claim 14, characterized in that: and E, adjusting the switching valve to close the second switch valve (5) and open the first switch valve (4) and the third switch valve (6).

18. A thermal cracking chromatographic detector capable of carrying out the thermal cracking chromatographic detection method of claim 1, comprising: the sample introduction device (2) is respectively communicated with the carrier gas and the chromatographic column (7), a gas passage is formed among the carrier gas, the chromatographic instrument (7) and the detector (11) are communicated to form the gas passage, and the detector (11), the signal amplifier, the chromatographic workstation and the computer are connected through electric signals.

19. A thermal cracking chromatographic detector capable of carrying out the thermal cracking chromatographic detection method of claim 18, further comprising: a pressure sensor (16) is arranged on an airtight passage formed between the sample introduction device (2) and the carrier gas.

20. A thermal cracking chromatographic detector capable of implementing the thermal cracking chromatographic analysis detection method as claimed in claim 13, wherein the sample injection device (2) comprises a thermal cracking device (21) and a sample injector (22) which are communicated, the thermal cracking device (21) comprises a sealing connector (212) which is provided with a communication hole communicated with a gas pipe i (8) and communicated with a carrier gas, an adjustable second switch valve (5) is arranged on the gas pipe i (8) and used for opening or closing a gas circuit, the sample injector (22) is communicated with a chromatographic column (7) to form a gas-tight gas circuit, and the chromatographic column (7) is communicated with the detector (11) and used for forming a gas circuit capable of detecting a sample by opening the second switch valve (5).

21. The thermal cracking chromatographic detector capable of realizing the thermal cracking chromatographic analysis detection method in claim 14 is characterized in that the sample injection device (2) comprises a thermal cracking device (21) and a sample injector (22) which are communicated with each other, the sample injector (22) comprises a sample injection pipe (221), the sample injection pipe (221) is provided with a carrier gas outlet communicated with a carrier gas through a gas pipe III (9), and is provided with a branch outlet (224) communicated with the external atmosphere through a hose, the gas pipe III (9) is provided with an adjustable third switch valve (6) for opening or closing a gas circuit, the thermal cracking device (21) comprises a sampling pipe (211) and a sealing connecting piece (212), the sealing connecting piece (212) is provided with a communication hole communicated with a hose II (10), the hose II (10) is provided with an adjustable first switch valve (4) for opening or closing the gas circuit, and is communicated with the outside atmosphere to form a back-blowing outlet (15), and the gas is discharged by opening a gas passage formed by the first switch valve (4) and the third switch valve (6).

22. A thermal cracking chromatographic detector capable of carrying out the thermal cracking chromatographic detection method of claim 21, further comprising: a back-blowing flow sensor (17) arranged on the hose II (10), and a shunt valve (19) and a shunt flow sensor (18) are sequentially arranged on the shunt outlet hose on the injector (22).

23. A thermal cracking chromatography detector capable of carrying out the thermal cracking chromatography detection method according to any one of claims 18 to 22, characterized in that: it still includes: chromatographic column (7) communicate sampling device (2) and detector (11) respectively, forms the gas circuit between the three, be equipped with the intercommunicating pore on sealing connector (212) in pyrolysis ware (21) in sampling device (2) and connect trachea I (8), injection pipe (221) is equipped with carrier gas export (223) and is connected with trachea III (9) in injection ware (22) in sampling device (1), trachea I (8) and trachea III (9) are through valve and carrier gas intercommunication, sealing connector (212) intercommunicating pore and hose II (10) intercommunication form and wash the export, be equipped with first ooff valve (4) on trachea I (8), be equipped with second ooff valve (5) on trachea III (9), be equipped with third ooff valve (6) on hose II (10) for control gas circuit, detector (11) connection signal amplifier, The chromatographic workstation and the computer are used for processing and calculating, and the computer is used for displaying the graphical detection result.