CN114371245A

CN114371245A - Low-heat-capacity micro-chromatographic column box system, and atmospheric organic matter online measurement system and method

Info

Publication number: CN114371245A
Application number: CN202210072336.3A
Authority: CN
Inventors: 杜玥萱; 胡丹; 张文凭; 敖小强
Original assignee: Beijing SDL Technology Co Ltd
Current assignee: Beijing SDL Technology Co Ltd
Priority date: 2022-01-21
Filing date: 2022-01-21
Publication date: 2022-04-19

Abstract

The application provides a miniature chromatographic column case system of low heat capacity includes: the device comprises one or more than two low-heat-capacity micro chromatographic column boxes, wherein each low-heat-capacity micro chromatographic column box comprises a box body and a chromatographic column arranged in the box body; and a heating unit; the one or more than two low heat capacity micro chromatographic column boxes are integrated in the same control system; the application also provides an online measuring system for the atmospheric organic matters. The invention can carry out multi-column incubator integrated design according to the variety requirements of measured substances, namely, a plurality of (2 or more) micro column incubators can be integrated in one module, and the high-precision program temperature rise requirements of various types of organic matters with different physicochemical characteristics can be met. The low heat capacity micro chromatographic column box system is small in design volume, and can be subjected to unified circuit gas circuit control, so that independent program temperature rise control of each column temperature box is realized, and the column temperature boxes are independent and unified.

Description

Low-heat-capacity micro-chromatographic column box system, and atmospheric organic matter online measurement system and method

Technical Field

The invention belongs to the technical field of environmental monitoring, and particularly relates to a low-heat-capacity micro chromatographic column box system, an atmospheric organic matter online measurement system and an atmospheric organic matter online measurement method.

Background

Atmospheric organics are quite complex and can exist in both the gas phase and the particulate phase. Organic materials can be classified into Volatile Organic Compounds (VOCs), Semi-Volatile Organic Compounds (SVOCs), and particulate phase Organic Compounds (Organic Aerosol OA) according to their volatility. Under normal temperature and pressure, VOCs mainly exist in the atmosphere in a gaseous state, SVOCs exist in both a gas phase and a particle phase, and OA mainly exists in the particle phase.

The gas phase/particle phase organic matter is an important precursor for the generation of near-surface ozone and fine particles, namely O in the atmosphere₃VOCs, SVOCs and OA can be mutually converted to form dynamic balance under certain conditions, and the composite pollution process of the atmosphere is influenced. The online real-time measurement of the atmospheric gas phase and particle phase organic matters is the basis for researching the pollution characteristics, sources and material conversion of the atmospheric organic matters, and effective O3 and PM are formulated_2.5The pollution control strategy has important scientific significance and practical effect. However, the knowledge and measurement means of the concentration distribution and substance conversion of various organic substances in the atmosphere, especially VOCs, SVOCs and OA, are not comprehensive at present.

At present, almost no direct synchronous online measurement technology for VOCs, SVOCs and OA multi-species organic matters exists at home and abroad, and the synchronous measurement of the three substances is mainly offline measurement, namely, VOCs, SVOCs and OA are subjected to long-time large-flow active pump suction by adopting various stainless steel tanks, adsorbents and filter membranes, and then are taken to a laboratory for a series of offline post-treatment and detection. Compared with the offline sampling technologies of organic matters such as adsorbent sampling, derivative adsorption sampling, stainless steel tank sampling, filter membrane sampling and the like, the online measurement technology has obvious advantages in the aspects of measurement time resolution, real-time performance of data, economy and the like. However, the existing online monitoring equipment is difficult to meet the synchronous real-time monitoring requirement of atmospheric multi-component organic matters (especially semi-volatile organic matters and granular phase organic matters), and a system for online identifying chemical compositions and realizing quantitative analysis of the chemical compositions aiming at SVOCs and OA is not provided in China.

The online measurement method for VOCs, SVOCs or OA single species at home and abroad mainly comprises the following means. The online measurement method of VOCs is mature, and detection is basically carried out by combining adsorbent enrichment with GCMS. But the online measurement method for large-molecular SVOCs and OA is relatively lacked. For the OA on-line measurement technique of large molecular weight, there is mainly an on-line aerosol thermal desorption gas chromatography measurement system (TAG system) capable of on-line measuring organic components in the particle phase from the molecular level. The TAG system was first reported by Williams et al (2006) at Berkeley division, California university, USA. Subsequently, Goldstein et al performed a series of studies to improve on the TAG system: such as two-dimensional chromatography, semi-volatile organic compounds measurement system (SV-TAG), on-line derivatization devices, etc. For the SVOCs on-line measurement technology of middle volatile substances, most of the existing detection methods can only measure the total amount of semi-volatile organic compounds, or obtain the gas content by subtracting the content difference between the total amount and the particle phase, such as two-position gas chromatography, a semi-volatile organic compound measurement system (SV-TAG), etc., however, the indirect measurement of the gas phase SVOC causes large errors.

Gas chromatography has become one of the most widely used methods for analyzing compounds because of its high sensitivity, stable operation and inexpensive price of analytical instruments. The conventional gas chromatograph is usually large in volume and mainly applied to an analysis laboratory, so that the wider application environment of the gas chromatograph is greatly limited. The most important reason for the large size of gas chromatographs is their large column box. The general chromatographic column box mainly controls the temperature of air in the column box in a radiation heat conduction mode, and the efficiency is relatively low. However, in practice, the volume of the chromatographic column is relatively small, and necessary temperature control can be directly performed on the chromatographic column, so that a miniaturized and portable chromatographic column box is realized, further the miniaturization of the chromatograph is promoted, and the wide application prospect of the chromatograph is expanded.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a low-heat-capacity miniature chromatographic column box system which is stable and reliable and has high temperature control precision.

The technical scheme of the invention is as follows:

1. a low heat capacity mini chromatography column cassette system comprising:

one or more than two low heat capacity micro chromatographic column boxes,

the low heat capacity micro chromatographic column box comprises a box body and a chromatographic column arranged in the box body; and a heating unit;

the one or more than two low heat capacity micro chromatographic column boxes are integrated in the same control system;

preferably, the volume of the box is 5cm x 5cm to 20cm x 10 cm.

2. The low heat capacity mini chromatography column cartridge system according to item 1,

the heating unit is a resistance wire wound outside the chromatographic column;

preferably, the resistance wire is an insulating resistance wire, and the resistance wire can heat the chromatographic column to 50-350 ℃;

further preferably, the resistance wire can enable the temperature rise rate of the chromatographic column to be 2-60 ℃/min, and the resistance wire can enable the temperature control precision of the chromatographic column to be +/-0.2 ℃.

3. The low heat capacity mini chromatography column cartridge system according to item 1,

the low heat capacity micro chromatographic column box also comprises a heat preservation unit;

preferably, the heat preservation unit is arranged inside the box body and on the periphery of the box body;

further preferably, the heat preservation unit is a heat preservation material wound inside and around the box body;

still further, the thermal insulation material is selected from aluminum silicate ceramic fiber cotton.

4. The low heat capacity mini chromatography column cartridge system according to item 3,

the low heat capacity micro chromatographic column box also comprises a heat dissipation unit; the heat dissipation unit is positioned at the bottom of the box body;

preferably, the heat dissipation unit is a fan.

5. The low heat capacity mini chromatography column cartridge system according to item 4,

the chromatographic column is a metal capillary column and is selected from one of an RTX-624 chromatographic column, an RTX-5 chromatographic column and an RTX-5 chromatographic column.

6. The low heat capacity mini chromatography column cartridge system according to item 5,

the low heat capacity micro chromatographic column box comprises a first transmission pipeline, and a sample flowing out of the chromatographic column is collected on a main transmission pipeline through the first transmission pipeline;

preferably, the main transfer line comprises:

a line for connecting a chromatography column;

a support pipe for supporting the stainless steel pipeline;

the heating layer is wound on the frame type supporting pipe;

the heat insulation layer is wound on the periphery of the main transmission flow path;

further preferably, the heat-resistant temperature of the main transfer flow path is 150 to 350 ℃.

7. An atmospheric organic matter on-line measuring system, comprising:

the atmospheric organic enrichment and desorption pretreatment device divides an atmospheric sample into volatile organic compounds, semi-volatile organic compounds and particle phase organic compounds;

the low heat capacity micro chromatographic column box system of any one of items 1 to 6 connected to the pretreatment apparatus;

a mass spectrometer;

the pre-treatment device for the enrichment and desorption of the organic matters in the atmosphere is connected with a low-heat-capacity miniature chromatographic column box system through a fluid channel;

the low heat capacity miniature chromatographic column box is connected with a mass spectrometer through a four-way valve.

8. The atmospheric organic matter on-line measuring system according to item 7,

the pretreatment device for enrichment and desorption of the organic matters in the atmosphere comprises a pretreatment device for enrichment and desorption of volatile organic matters, a pretreatment device for enrichment and desorption of semi-volatile organic matters and a pretreatment device for enrichment and desorption of organic matters in a particle phase;

the low heat capacity micro chromatographic column box system comprises a volatile organic matter low heat capacity micro chromatographic column box, a semi-volatile organic matter low heat capacity micro chromatographic column box and a particle phase organic matter low heat capacity micro chromatographic column box;

the low-heat-capacity micro-chromatographic column box for the volatile organic compounds is connected with the pre-enrichment and desorption treatment device for the volatile organic compounds, the low-heat-capacity micro-chromatographic column box for the semi-volatile organic compounds is connected with the pre-enrichment and desorption treatment device for the semi-volatile organic compounds, and the low-heat-capacity micro-chromatographic column box for the particle-phase organic compounds is connected with the pre-enrichment and desorption treatment device for the particle-phase organic compounds;

preferably, a first chromatographic column is arranged in the volatile organic low-heat-capacity micro chromatographic column box, a second chromatographic column is arranged in the semi-volatile organic low-heat-capacity micro chromatographic column box, and a third chromatographic column is arranged in the particle-phase organic low-heat-capacity micro chromatographic column box;

further preferably, the first chromatographic column is an RTX-624 chromatographic column, and the heating temperature is 50-250 ℃; the second chromatographic column is an RTX-5 chromatographic column, and the heating temperature is 50-300 ℃; the third chromatographic column is an RTX-5 chromatographic column, and the heating temperature is 50-350 ℃.

9. The atmospheric organic matter on-line measuring system according to item 8,

a first fluid channel is arranged between the volatile organic compound low heat capacity micro chromatographic column box and the volatile organic compound enrichment and pretreatment device, and preferably, the first fluid channel is an 1/32' flexible inerting stainless steel tube with the inner diameter of 0.32 mm;

a second fluid channel is arranged between the semi-volatile organic low-heat capacity micro chromatographic column box and the semi-volatile organic enrichment and desorption pretreatment device, and preferably, the second fluid channel is an 1/16' flexible inerting stainless steel tube with the inner diameter of 0.32 mm;

a third fluid channel is arranged between the particle-phase organic matter low-heat-capacity micro chromatographic column box and the particle-phase organic matter enrichment and desorption pretreatment device, and preferably, the third fluid channel is an 1/16' rigid inerting stainless steel tube with the inner diameter of 0.25 mm;

preferably, the second fluid passage and the third fluid passage each comprise:

a line for connecting a chromatography column;

a support pipe for supporting the stainless steel pipeline;

the heating layer is wound on the frame type supporting pipe;

the heat insulation layer is wound on the periphery of the fluid channel;

it is further preferred that the first and second liquid crystal compositions,

the heat-resistant temperature of the second fluid channel is 100-350 ℃;

the heat-resistant temperature of the third fluid channel is 100-350 ℃.

10. The atmospheric organic matter on-line measuring system according to item 9,

the main transmission pipeline of the volatile organic low-heat capacity micro chromatographic column box and the main transmission pipeline of the semi-volatile organic low-heat capacity micro chromatographic column box are connected to a first four-way valve;

the main transmission pipeline of the particle-phase organic matter low-heat-capacity miniature chromatographic column box is connected to the second four-way valve;

the first four-way valve is connected with the second four-way valve;

the second four-way valve is connected with the mass spectrometer through a first transmission channel;

preferably, the first transfer channel is an 1/16' rigid inerted stainless steel tube having an inner diameter of 0.25 mm.

11. The online measurement method of the atmospheric organic matter online measurement system according to any one of claims 7 to 10, comprising:

and (3) aging: aging and purging are carried out on the atmospheric organic matter enrichment and desorption pretreatment device and the transmission line thereof;

a sampling step: enriching the atmospheric organic matters in the pretreatment device for enriching and desorbing the atmospheric organic matters;

a purging step: purging the pre-treatment device for enriching and desorbing the organic matters in the atmosphere and the transmission flow path;

a sample introduction step: carrying the enriched atmospheric organic matters into a low heat capacity micro chromatographic column box system and a subsequent mass spectrum, and separating and measuring the low heat capacity micro chromatographic column box system and the subsequent mass spectrum;

preferably, the sampling step includes:

enriching volatile organic matters in the atmospheric organic matters into the volatile organic matter enrichment and desorption pretreatment device, enriching semi-volatile organic matters in the atmospheric organic matters into the semi-volatile organic matter enrichment and desorption pretreatment device, and enriching particle-phase organic matters in the atmospheric organic matters into the particle-phase organic matter enrichment and desorption pretreatment device;

further preferably, the sample injection step comprises:

carrying the volatile organic compounds enriched in the sampling step into a low heat capacity miniature chromatographic column box system for separation, and then, entering a mass spectrometer for measurement;

carrying the semi-volatile organic matters enriched in the sampling step into a low heat capacity micro chromatographic column box system for separation, and then, entering a mass spectrometer for measurement;

carrying the enriched particle phase organic matters in the sampling step into a low heat capacity miniature chromatographic column box system for separation, and then, entering a mass spectrometer for measurement;

more preferably, the sample injection step comprises:

carrying the volatile organic compounds enriched in the sampling step into a low-heat-capacity micro chromatographic column box for separation, and then, entering a mass spectrometer for measurement;

carrying the semi-volatile organic matters enriched in the sampling step into a low-heat-capacity micro chromatographic column box for separation, and then, entering a mass spectrometer for measurement;

and (3) carrying the enriched particle-phase organic matters in the sampling step into a low-heat-capacity micro chromatographic column box for separation, and then, entering a mass spectrometer for measurement.

Compared with the prior art, the invention has the following effects:

(1) based on the low heat capacity chromatographic technology, a low heat capacity micro chromatographic column box system meeting the requirements of measuring substances with different characteristics is designed. The system not only expands the monitoring range of the system, but also improves the detection speed, and has the characteristics of small volume and high temperature rise and fall speed.

(2) The low-heat-capacity miniature chromatographic column box system can be used for carrying out multi-column incubator integrated design according to the type requirements of measured substances, namely, a plurality of (2 or more) miniature column incubators can be integrated in one module, and the high-precision temperature programming requirement of various organic matters with different physicochemical characteristics can be met. The low heat capacity micro chromatographic column box system is small in design volume, and can be subjected to unified circuit gas circuit control, so that independent program temperature rise control of each column temperature box is realized, and the column temperature boxes are independent and unified.

(3) The online measurement system for the atmospheric organic matters introduces a composite sample introduction technology which can connect a low-heat-capacity micro chromatographic column box system with a mass spectrometer, namely, one mass spectrometer can meet the separation measurement requirements of three types of substances (VOCs, SVOCs and OA) through switching of valves. The composite sample introduction technology can realize sequential sample introduction of different substances or direct sample introduction requirements of specific substances through control according to customer requirements.

(4) The on-line measurement system for the atmospheric organic matters can realize the measurement of a plurality of substances from gas phase to particle phase, meets the measurement requirement of the current atmospheric combined pollution, and provides data support for scientific pollution control. Meanwhile, the whole volume of the atmospheric organic matter online measurement system is small, the transportation of instruments can be conveniently realized, and the purpose of monitoring substances from the north to the south and from cities to villages can be met according to the requirements of measured substances (gas phase or particle phase).

(5) The external physical size of the conventional chromatographic column box is about 300mm x 300mm (length x width x height), and the minimum external physical size of the box is about 5mm x 5mm (length x width x height), so that the size of the box is greatly reduced, and the miniaturization purpose is achieved.

Drawings

FIG. 1A is a schematic diagram of the low heat capacity micro chromatographic column housing of the present invention;

FIG. 1B is a top view of a low heat capacity micro chromatography column cassette of the present invention;

FIG. 2 is a schematic structural view of a low heat capacity micro chromatographic column box system and a mass spectrometer of the present invention;

FIG. 3 is a schematic structural diagram of an online measurement system for atmospheric organic compounds according to the present invention;

FIG. 4 is a schematic structural view of the primary transfer flow path and fluid channels of the present invention;

description of the symbols:

1, a high-precision temperature sensor; 2 high temperature resistant insulated transmission pipeline; 3, heating a pipeline by a chromatographic column;

4, a heat radiation fan; 5, a heat preservation unit; 6 insulating resistance wires; 7, a chromatographic column; 8, a box body;

a 15-VOCs chromatographic column box; 16-SVOCs chromatography column box; a 17-OA chromatography column box;

a first fluid channel of 18-VOCs; 19-SVOCs second fluid channel; a 20-OA third fluid channel; 21-VOCs main transmission pipeline; 22-SVOCs main transmission pipeline; a 23-OA primary transport line;

24-a first transmission channel; 27-a first four-way valve; 28-a second four-way valve; 29-mass spectrum;

30-a volatile organic compound enrichment and desorption pretreatment device; 31-a semi-volatile organic matter enrichment and desorption pretreatment device; 32-a particle phase organic matter enrichment and desorption pretreatment device; 34-silanized line; 35-support tube; 36-a heating layer; 37-insulating layer.

Detailed Description

Specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While specific embodiments of the invention are shown in the drawings, it should be understood that the invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

According to the difference of the volatilization characteristics of the atmospheric organic matters, the atmospheric organic matters can be divided into volatile organic matters, semi-volatile organic matters and particle-phase organic matters. By respectively constructing the pretreatment and enrichment devices, designing a chromatographic separation integrated module (comprising a special chromatographic column and program temperature control) matched with the pretreatment and enrichment devices, and combining a mass spectrum detection module, a control system and a data processing software system, the real-time collection, enrichment, thermal analysis, separation and detection of the atmospheric volatile/semi-volatile/particle phase organic matters are finally realized, and a set of high-sensitivity online measurement system for the atmospheric low-concentration multi-component organic matters is formed.

Volatile Organic Compounds (VOCs): VOCs, according to the definition of the world health organization WHO, refer to various organic compounds having a boiling point of between 50 ℃ and 260 ℃ at atmospheric pressure (WHO,1989)

Semi-volatile organics (SVOCs): SVOC is defined as an organic compound boiling between 240 ℃ and 400 ℃ (WHO, 1997).

Particulate phase Organic (OA): the Organic Aerosol (OA) is an important component in PM2.5 and accounts for 20-90% of the mass concentration of PM 2.5.

The invention provides a low heat capacity miniature chromatographic column box system, comprising:

comprises one or more than two low heat capacity micro chromatographic column boxes,

the one or more than two low heat capacity micro chromatographic column boxes are integrated in the same control system.

In some embodiments of the invention, the low heat capacity micro chromatography column box system comprises a volatile organic low heat capacity micro chromatography column box, a semi-volatile organic low heat capacity micro chromatography column box and a particulate phase organic low heat capacity micro chromatography column box.

In order to reduce the overall volume of the system and expand the practicability of the system, each column box in the low heat capacity micro-chromatographic column box system is designed in a minimized mode, a cube of 5cm x 5 cm-20 cm x 10cm is used as a bearing micro-column box of the chromatographic column, for example, the column box can be 10cm x 5cm, and the column box is made of 316 stainless steel materials.

In some embodiments of the invention, the volume of the microcolumn box can be 5cm x 5cm, 10cm x 5cm, 15cm x 5cm, 20cm x 5cm, 5cm x 10cm 5cm, 10cm x 10cm 5cm, 15cm x 10cm 5cm, 20cm x 10cm 5cm, 5cm x 15cm 5cm, 10cm x 15cm 5cm, 15cm x 15cm 5cm, 20cm x 15cm 5cm, 5cm x 20cm 5cm, 10cm x 10cm 5cm, 10cm x 20cm 5cm, 10cm x 10cm x 5cm, 15cm x 10cm, 10cm x 5cm, 10cm x 10cm, 10cm 5cm, 10cm x 5cm, 10cm x 5cm, 10cm, 10cm 5cm, 10cm, 10cm, 10cm 5cm, 10cm, 10cm, 10cm, 10cm, 10cm, 10cm, 10cm, 10cm, 10cm, 10cm, cm, 15cm x 10cm, 20cm x 15cm x 10cm, 5cm x 20cm x 10cm, 10cm x 20cm x 10cm, 15cm x 20cm x 10cm, 20cm x 10cm, or any range therebetween.

In some embodiments of the invention, three low heat capacity micro-chromatography column cassettes are integrated: the design of the low heat capacity mini-chromatography column box system requires the completion of serial analysis of VOCs, SVOCs and OA samples. Therefore, an integrated design of three low heat capacity micro chromatographic column boxes is required, and the three low heat capacity micro chromatographic column boxes (namely, the VOCs column box, the SVOCs column box and the OA column box) are integrated in one low heat capacity micro chromatographic column box system to carry out uniform temperature programming, carrier gas pressure and flow control, so that the three modules can work cooperatively.

In some embodiments of the invention, three chromatography column boxes, such as a volatile organic low heat capacity mini chromatography column box (i.e., a VOCs chromatography column box), a semi-volatile organic low heat capacity mini chromatography column box (i.e., a SVOCs chromatography column box), and a particulate phase organic low heat capacity mini chromatography column box (an OA chromatography column box) are placed in a module and are subjected to uniform condition parameter control. The three low heat capacity micro chromatographic column boxes are independent and coordinated with each other, the independent conditions are different process rise conditions of different chromatographic columns, and the mutual coordination is realized by that the three low heat capacity micro chromatographic column boxes use the same control system to uniformly control the flow, the temperature and the pressure of the three column temperature boxes, namely three sets of parameters are integrated into one integrated module, and the integrated module is controlled.

When the system is integrated, the arrangement of the three low heat capacity micro chromatographic column boxes can be set according to actual needs, and the route between sample transmission processes can be reduced as much as possible by a person skilled in the art.

The low heat capacity micro chromatographic column box system realizes the control of the flow, the voltage and the programmed temperature of the system through a control circuit. The control circuit adopts a double-CPU structure, the CPU1 is a CPU with an MCS51 framework, and is mainly used for temperature control (including heating and temperature control) of a sample transmission flow path, a fluid channel and a transmission channel; the CPU2 adopts an ARM-based CPU, and is mainly used for temperature control, valve box temperature control, and EPC pressure control of each low heat capacity micro-chromatography column box, and also can be used for start-stop control of a volatile organic compound enrichment and desorption pretreatment device, a semi-volatile organic compound enrichment and desorption pretreatment device, and a particle-phase organic compound enrichment and desorption pretreatment device. The CPU1 and the CPU2 communicate via I2C to transfer control and status information.

The main functions of the control circuit are as follows:

the coordination work of three chromatographic column box (a volatile organic matter low heat capacity micro chromatographic column box, a semi-volatile organic matter low heat capacity micro chromatographic column box and a particle-phase organic matter low heat capacity micro chromatographic column box) modules and a four-way valve switchable interface device is controlled; controlling each chromatographic column box module to carry out temperature programming, carrier gas pressure and flow according to respective set conditions; and sending and receiving starting and range rising signals and the like of the atmospheric organic matter enrichment and desorption pretreatment device (a volatile organic matter enrichment and desorption pretreatment device, a semi-volatile organic matter enrichment and desorption pretreatment device and a particle-phase organic matter enrichment and desorption pretreatment device).

As shown in fig. 1A and 1B, wherein fig. 1A is a schematic view of a low heat capacity micro chromatography column box, and fig. 1B is a top view of the low heat capacity micro chromatography column box in fig. 1A. The low heat capacity micro column box comprises a box body, a column 7 arranged in the box body and a heating unit. In some embodiments of the invention, the low heat capacity micro chromatographic column box adopts an LTM structure, namely a resistance wire winding heating structure, wherein the heating unit is a resistance wire 6 wound outside the chromatographic column, the resistance wire is an insulating resistance wire, in the invention, the insulating resistance wire is alternately wound on the chromatographic column layer by layer in a crossing manner, and by adopting the uniform and encrypted heating mode, the contact area between the chromatographic column and the resistance wire is greatly increased, so that the chromatographic column is uniformly heated, and the temperature gradient of each point in the column can be effectively reduced. By adopting the heating unit, the resistance wire can heat the chromatographic column to 50-350 ℃, the resistance wire can heat the chromatographic column at a temperature rise rate of 2-60 ℃/min, and the resistance wire can control the temperature of the chromatographic column to +/-0.2 ℃.

In some embodiments of the present invention, a 30m long chromatographic column is straightened, a resistance wire is wound on the chromatographic column layer by layer to ensure uniform contact between the chromatographic column and a heating wire, and then the wound chromatographic column is coiled and placed in a 10cm by 10cm mini-column incubator.

As shown in fig. 1B, the low heat capacity micro-chromatography column box further includes a temperature keeping unit 5: the heat preservation unit 5 is arranged in the box body and on the periphery of the box body; the heat preservation unit is a heat preservation material wound inside and on the periphery of the box body. In order to reduce the temperature difference heat dissipation phenomenon of the low-heat-capacity micro chromatographic column box at high temperature, the inner part of the low-heat-capacity micro chromatographic column box and the outer surface of a chromatographic column are subjected to heat preservation design, and specifically, cellucotton with a good heat preservation effect is uniformly spread on each surface of the low-heat-capacity micro chromatographic column box, so that the temperature discrimination of the low-heat-capacity micro chromatographic column box at high-temperature separation is reduced. The heat preservation cotton is arranged on the inner layer of the chromatographic column, the outer layer of the chromatographic column after the resistance wire is wound and the inner surface of the low-heat-capacity miniature chromatographic column box. In order to enhance the heat preservation performance, the invention adopts the aluminum silicate ceramic fiber cotton heat preservation material which can resist 1000 ℃, and provides an excellent temperature environment and heat preservation capability, which is very beneficial to the improvement and control effect of the temperature characteristic of the whole column box.

As shown in fig. 1B, a heat dissipation unit is further included in the low heat capacity micro-chromatography column box: the heat dissipation unit is positioned at the bottom of the box body and is a heat dissipation fan 4. In the invention, the fan is arranged at the bottom of the low-heat-capacity micro chromatographic column box, and the chromatographic column is blown upwards by the fan during temperature reduction, so that the temperature of the chromatographic column is reduced. The cooling of the low-heat capacity miniature chromatographic column box adopts a high-power direct-current fan air cooling mode, and the fast cooling of the chromatographic column box can be realized in view of the characteristic of small volume of the column incubator.

As shown in fig. 1B, the low heat capacity micro-chromatographic column box further comprises a sensor 1, wherein the sensor is a high-precision temperature sensor, and the sensor is deeply inserted into the wound chromatographic column and is used for monitoring the real-time temperature of the chromatographic column. Still include chromatographic column heating pipeline 3 in the miniature chromatographic column case of low heat capacity, the both ends of heating pipeline are connected with the resistance wire both ends of winding on the chromatographic column, adopt direct current 24V resistance wire heating to realize the intensification of chromatographic column. In order to avoid the phenomena of melting of the outer skin and electric leakage of the pipeline in the high-temperature period of the column temperature box, the pipeline in the low-heat-capacity miniature chromatographic column box is wrapped by a high-temperature-resistant insulating material, namely the high-temperature-resistant insulating transmission pipeline 2, and all pipelines passing through the column temperature box are protected by the high-temperature-resistant insulating transmission pipeline. Wherein, the high temperature resistant insulating material is a glass fiber high temperature sleeve.

In some embodiments of the present invention, the chromatographic column is a metal capillary column, and a silanized Restek stainless steel metal capillary column is adopted, and the chromatographic column is selected from one of an RTX-624 chromatographic column, an RTX-5 chromatographic column and an RTX-5 chromatographic column, and has the characteristics of good thermal conductivity and difficult fracture when being coiled.

In some embodiments of the invention, the volatile organic compounds low heat capacity micro chromatographic column box (i.e. the VOCs chromatographic column box) adopts an RTX-624 chromatographic column, wherein the chromatographic column is a metal capillary column, the length of the column is 60m, the inner diameter of the column is 0.25mm, the thickness of the membrane is 1.4um, the maximum heating temperature is 250 ℃, and the maximum heating rate is 30 ℃/min.

In some embodiments of the invention, the low heat capacity micro chromatographic column box (i.e. SVOCs chromatographic column box) for semi-volatile organic compounds adopts RTX-5 chromatographic column, wherein the chromatographic column is a metal capillary column, the length of the column is 30m, the inner diameter is 0.25mm, the thickness of the membrane is 0.25um, the maximum heating temperature is 300 ℃, and the maximum heating rate is 30 ℃/min.

In some embodiments of the invention, the particle phase organic matter low heat capacity micro chromatographic column box (OA chromatographic column box) adopts an RTX-5 chromatographic column, wherein the chromatographic column is a metal capillary column, the length of the column is 30m, the inner diameter of the column is 0.25mm, the thickness of the membrane is 0.25um, the maximum heating temperature is 350 ℃, and the maximum heating rate is 60 ℃/min.

In some embodiments of the invention, the low heat capacity mini chromatography column box comprises a first transfer line, and the sample flowing out of the chromatography column is collected on a main transfer line through the first transfer line in a confluence mode. Each low heat capacity mini chromatography column box has its own main transfer line.

As shown in fig. 4, the main transmission pipeline sequentially includes, from inside to outside: stainless steel pipeline 34, frame type support pipe 35, heating layer 36 and heat preservation layer 37. Wherein, the stainless steel pipeline 34 is a stainless steel inerting pipeline used for connecting the chromatographic column and the four-way valve and used for transmitting the sample; a frame-type support tube 35 for supporting the stainless steel pipeline and internally laying an inerting pipeline; a heating layer 36 wound around the frame-type support tube; and the insulating layer 37 is wound on the periphery of the main conveying pipeline. The temperature control of the transmission pipeline adopts a closed loop control mode of thermocouple temperature measurement and direct current PWM heating. The heat-resistant temperature of the transmission pipeline is 150-350 ℃, certain high-boiling-point substances can be prevented from being condensed in the pipeline, and meanwhile, the transmission requirements of all samples of VOCs, SVOCs and OA can be met.

VOCs chromatographic column case includes first transmission line, adopts the mode of converging, will collect on VOCs chromatographic column case's main transmission line 21 from the sample of chromatographic column outflow through first transmission line.

The SVOCs column box includes a second transfer line, and the sample flowing out from the column is collected to the main transfer line 22 of the VOCs column box through the second transfer line in a confluence manner.

The OA chromatographic column box comprises a third transmission pipeline, and a sample flowing out of the chromatographic column is collected on the main transmission pipeline 23 of the VOCs chromatographic column box through the third transmission pipeline in a confluence mode.

As shown in FIG. 2 and FIG. 3, the present invention also provides an on-line measuring system for atmospheric organic compounds, comprising

the low heat capacity micro chromatographic column box system is connected with the pretreatment device;

a mass spectrometer;

As shown in fig. 2, in some embodiments of the present invention, the pretreatment apparatus for enrichment and desorption of atmospheric organic compounds includes a pretreatment apparatus 30 for enrichment and desorption of volatile organic compounds, a pretreatment apparatus 31 for enrichment and desorption of semi-volatile organic compounds, and a pretreatment apparatus 32 for enrichment and desorption of particulate organic compounds;

the low heat capacity micro chromatographic column box system comprises a volatile organic matter low heat capacity micro chromatographic column box 15, a semi-volatile organic matter low heat capacity micro chromatographic column box 16 and a particle-phase organic matter low heat capacity micro chromatographic column box 17;

as shown in fig. 3, the volatile organic compound low heat capacity micro chromatographic column box 15 is connected to the volatile organic compound enrichment and desorption pretreatment device 30, the semi-volatile organic compound low heat capacity micro chromatographic column box 16 is connected to the semi-volatile organic compound enrichment and desorption pretreatment device 31, and the particle phase organic compound low heat capacity micro chromatographic column box 17 is connected to the particle phase organic compound enrichment and desorption pretreatment device 32.

In some embodiments of the present invention, the volatile organic compound low heat capacity micro chromatographic column box 15 is provided with a first chromatographic column, RTX-624 chromatographic column, and the heating temperature thereof is 50-250 ℃; a second chromatographic column and an RTX-5 chromatographic column are arranged in the semi-volatile organic low-heat-capacity micro chromatographic column box 16, and the heating temperature is 50-300 ℃; the particle phase organic matter low heat capacity micro chromatographic column box 17 is internally provided with a third chromatographic column and an RTX-5 chromatographic column, and the heating temperature of the third chromatographic column is 50-350 ℃.

In some embodiments of the present invention, a first fluid channel 18 is disposed between the voc low heat capacity micro-chromatography column box and the voc pre-treatment device, that is, a first fluid channel of VOCs.

In some embodiments of the invention, the first fluid channel may be any fluid channel known in the art, in the present invention, a flexible passivated stainless steel tube of 1/16 "with a first fluid channel inner diameter of 0.32mm, or a 1/32" flexible inerted stainless steel tube with an inner diameter of 0.32mm, or a 1/32 "with an inner diameter of 0.25mm, or a 1/16" flexible passivated stainless steel tube with an inner diameter of 0.25 mm; preferably an 1/32 "flexible inerted stainless steel tube with an internal diameter of 0.32 mm.

In some embodiments of the present invention, a second fluid channel 19, that is, an SVOCs second fluid channel, is disposed between the semi-volatile organic low heat capacity micro chromatographic column box 16 and the semi-volatile organic enrichment and desorption pre-processing device 31. The second fluid channel has a structure as shown in fig. 4, is a silanized stainless steel tube, and comprises a stainless steel pipeline 34, a frame-type support tube 35, a heating layer 36 and an insulating layer 37, wherein the stainless steel pipeline is used for connecting a chromatographic column; wherein the stainless steel pipeline is a stainless steel inerting pipeline and is used for connecting the chromatographic column and the four-way valve and transmitting a sample; the frame type supporting pipe is used for supporting the stainless steel pipeline and internally laying an inerting pipeline; the heating layer is wound on the frame type supporting pipe; and the insulating layer is wound on the periphery of the second fluid channel. The heat-resistant temperature of the second fluid channel is 100-350 ℃, and high-boiling-point substances can be prevented from condensing in the pipeline.

In some embodiments of the invention, the second fluid passageway may be any fluid passageway known in the art, in the present invention, a flexible passivated stainless steel tube of 1/32 "with a second fluid passageway inner diameter of 0.32mm, or a 1/16" flexible inerted stainless steel tube with an inner diameter of 0.32mm, or a 1/32 "with an inner diameter of 0.25mm, or a 1/16" flexible passivated stainless steel tube with an inner diameter of 0.25 mm; preferably an 1/16 "flexible inerted stainless steel tube with an internal diameter of 0.32 mm.

In some embodiments of the present invention, a third fluid channel, that is, an OA third fluid channel, is disposed between the particle-phase organic matter low heat capacity micro-chromatography column box 17 and the particle-phase organic matter pre-enrichment and desorption treatment device 32; the third fluid channel has a structure as shown in fig. 4, is a stainless steel tube subjected to silanization treatment, and comprises a stainless steel pipeline 34, a frame-type support tube 35, a heating layer 36 and an insulating layer 37, wherein the stainless steel pipeline is used for connecting a chromatographic column; wherein the stainless steel pipeline is a stainless steel inerting pipeline and is used for connecting the chromatographic column and the four-way valve and transmitting a sample; the frame type supporting pipe is used for supporting the stainless steel pipeline and internally laying an inerting pipeline; the heating layer is wound on the frame type supporting pipe; and the heat insulation layer is wound on the periphery of the third fluid channel. The heat-resistant temperature of the third fluid channel is 100-350 ℃, and the high-boiling-point substances can be prevented from being condensed in the pipeline.

In some embodiments of the invention, the third fluid passageway may be any fluid passageway known in the art, in the present invention, a 1/16 "rigid inerted stainless steel tube with a third fluid passageway inner diameter of 0.25mm, or a 1/16" flexible passivated stainless steel tube with an inner diameter of 0.32mm, or a 1/32 "flexible passivated stainless steel tube with an inner diameter of 0.25 mm; preferably an 1/16' rigid inerted stainless steel tube with an internal diameter of 0.25 mm.

As shown in fig. 3, in some embodiments of the present invention, the main transfer lines of the voc low heat capacity micro chromatography column housings and the main transfer lines of the semi-voc low heat capacity micro chromatography column housings are connected to a first four-way valve 27; the main transmission pipeline of the particle-phase organic matter low heat capacity micro chromatographic column box is connected to a second four-way valve 28; the first four-way valve is connected with the second four-way valve; the second four-way valve is connected to the mass spectrometer via a first transmission channel 24. By adopting the design of two four-way valves, the sequential analysis of VOCs, SVOCs and OA by one mass spectrometer can be realized by switching the two four-way valves, the four-way valve in the invention adopts a high-temperature passivated four-way valve, the highest temperature can reach 350 ℃, and the sample adsorption can be effectively prevented; the whole four-way valve interface device can be heated to 300 ℃ to prevent the sample from condensing and adsorbing.

In some embodiments of the invention, the first transfer channel may be any transfer channel known in the art, and in the present invention, the first transfer channel is preferably a 1/16 "rigid inerted stainless steel tube with an inner diameter of 0.25mm, a 1/16" flexible passivated stainless steel tube with an inner diameter of 0.32mm, or a 1/32 "flexible passivated stainless steel tube with an inner diameter of 0.25mm, or a 1/32" flexible passivated stainless steel tube with an inner diameter of 0.32mm, preferably a 1/16 "rigid inerted stainless steel tube with an inner diameter of 0.25 mm.

Wherein the inner diameters of the main transmission pipeline and the first fluid channel (or the second fluid channel or the third fluid channel) are matched with the inner diameter of the first transmission channel.

In some embodiments of the present invention, the four-way valve may be any type of four-way valve known in the art, such as a pneumatically or electrically controlled four-way valve, with the use of an electrically controlled high temperature four-way valve being preferred herein for ease of integrated circuit design.

In some embodiments of the present invention, the two four-way valves may be the same or different.

In some embodiments of the present invention, the method for enriching the volatile organic compounds in the atmospheric organic compounds in the pre-volatile organic compound enrichment and desorption processing device 30, enriching the semi-volatile organic compounds in the atmospheric organic compounds in the pre-semi-volatile organic compound enrichment and desorption processing device 31, and enriching the particulate phase organic compounds in the atmospheric organic compounds in the pre-particulate phase organic compound enrichment and desorption processing device 32 may be any method known to those skilled in the art. Preferably, in the invention, volatile organic compounds and semi-volatile organic compounds are enriched in the enrichment and desorption pretreatment device by adopting a low-temperature adsorption collection technology and then carrying out high-temperature thermal desorption technology, and particulate phase organic compounds are collected by adopting a quartz filter membrane and enriched in the enrichment and desorption pretreatment device.

The invention also provides the application of the atmospheric organic matter on-line measuring system in the aspect of measuring the atmospheric organic matters.

The invention also provides an online measurement method of the online measurement system for the atmospheric organic matters, wherein the online measurement method comprises the following steps:

and (3) aging: aging and purging are carried out on the atmospheric organic matter enrichment and desorption pretreatment device and the transmission line;

a sample introduction step: and (3) bringing the enriched atmospheric organic matters in the step into a low heat capacity micro chromatographic column box system and a subsequent mass spectrometer, and separating and measuring the low heat capacity micro chromatographic column box system and the subsequent mass spectrometer.

In some embodiments of the present invention, the sample injection step comprises:

carrying the volatile organic compounds enriched in the sample introduction step into a low-heat-capacity micro chromatographic column box system of the volatile organic compounds for separation, and then, entering a mass spectrometer for measurement;

carrying the semi-volatile organic matters enriched in the sample introduction step into a low-heat-capacity micro chromatographic column box system of the semi-volatile organic matters for separation, and then, entering a mass spectrometer for measurement;

and carrying the particle phase organic matters enriched in the sample introduction step into a low heat capacity micro chromatographic column box system of the particle phase organic matters for separation, and then, entering a mass spectrometer for measurement.

In some embodiments of the present invention, in the aging step, the volatile organic compound enrichment and desorption pretreatment device 30, the semi-volatile organic compound enrichment and desorption pretreatment device 31, the particulate organic compound enrichment and desorption pretreatment device 32, and the transmission line thereof are sequentially subjected to carrier gas cleaning to remove the residual substances in the pipeline.

In some embodiments of the invention, in the sampling step, volatile organic compounds in the atmospheric organic compounds are sequentially enriched in the pre-processing device for volatile organic compound enrichment and desorption, semi-volatile organic compounds in the atmospheric organic compounds are enriched in the pre-processing device for semi-volatile organic compound enrichment and desorption, and particulate phase organic compounds in the atmospheric organic compounds are enriched in the pre-processing device for particulate phase organic compound enrichment and desorption.

In some embodiments of the present invention, in the purging step, the pre-volatile organic compound enrichment and desorption processing device 30, the pre-semi-volatile organic compound enrichment and desorption processing device 31, the pre-particulate organic compound enrichment and desorption processing device 32, and the transmission line thereof are sequentially purged to remove the residual oxygen and other unwanted interfering gases.

and carrying the enriched particle phase organic matters in the sampling step into a low heat capacity micro chromatographic column box system for separation, and then, entering a mass spectrometer for measurement.

Completing a sampling and analyzing cycle;

if the detection is needed to be continued, the steps are circulated.

carrying the particle phase organic matters enriched in the sampling step into a particle phase organic matter low heat capacity micro chromatographic column box for separation, and then, entering a mass spectrometer for measurement;

completing a sampling and analyzing cycle;

if the detection is needed to be continued, the steps are circulated.

The low heat capacity micro chromatographic column box system can carry out multi-column incubator integrated design according to the variety requirements of measured substances, namely 3 micro column incubators with different functions can be integrated in one module, and the high-precision program heating requirements of various types of organic matters with different physical characteristics can be met. The low heat capacity micro chromatographic column box system is small in design volume, and can be subjected to unified circuit gas circuit control, so that independent program temperature rise control of each column temperature box is realized, and the column temperature boxes are independent and unified.

The online measurement system for the atmospheric organic matters can connect the low-heat-capacity micro chromatographic column box system with a mass spectrometer, namely, one mass spectrometer can meet the separation measurement requirements of three types of substances (VOCs, SVOCs and OA) through switching of two valves. According to the requirements of customers, the sequential sample injection of different substances or the direct sample injection requirement of specific substances is realized.

The on-line measurement system for the atmospheric organic matters can realize the measurement of a plurality of substances from gas phase to particle phase, meets the measurement requirement of the current atmospheric combined pollution, and provides data support for scientific pollution control. Meanwhile, the whole volume of the atmospheric organic matter online measurement system is small, the transportation of instruments can be conveniently realized, and the purpose of monitoring substances from the north to the south and from cities to villages can be met according to the requirements of measured substances (gas phase or particle phase).

Examples

Example 1 design of a volatile organic Low Heat Capacity Microchromatography column Box

The volatile organic compound low heat capacity miniature chromatographic column box (VOCs chromatographic column box) comprises a box body, and an RTX-624 chromatographic column 7, a heating unit, a heat preservation unit 5 and a heat dissipation unit which are arranged in the box body. The box body adopts a column box of 10cm by 5cm, and the column box adopts 316 stainless steel materials. The heating unit adopts an LTM structure, namely a resistance wire winding heating structure, specifically, an RTX-624 chromatographic column is straightened, insulation resistance wires 6 are wound on the chromatographic column layer by layer to ensure that the chromatographic column is uniformly contacted with a heating wire, and then the wound RTX-624 chromatographic column is coiled and placed in a 10 cm-5 cm miniature column temperature box. By adopting the structure, the contact area of the RTX-624 chromatographic column and the resistance wire is greatly increased, so that the chromatographic column is uniformly heated, and the temperature gradient of each point in the column can be effectively reduced. The maximum temperature of the chromatographic column box can reach 330 ℃, the maximum heating rate can reach 60 ℃/min, the constant temperature precision is +/-0.2 ℃, and the analysis requirements of high-boiling point and low-volatility organic matter components in the atmosphere can be met by selecting 50W of heating power. The heat preservation unit 5 is arranged in the box body and on the periphery of the box body, and fiber cotton with better heat preservation effect is uniformly spread on each surface of the low-heat-capacity micro chromatographic column box. The heat preservation cotton is arranged on the inner layer of the chromatographic column, the outer layer of the chromatographic column after the resistance wire is wound and the inner surface of the low-heat-capacity miniature chromatographic column box. In order to enhance the heat preservation performance, the invention adopts an aluminum silicate ceramic fiber cotton heat preservation material which can resist 1000 ℃. The fan is located the bottom half, adopts high-power direct current fan air cooling mode, in view of the small characteristics of column incubator, can realize the rapid cooling of column case. Through the design, the miniature column box has the characteristics of small volume, high temperature rise and drop rate and convenience for integration.

VOCs chromatographic column case includes first transmission line, adopts the mode of converging, will collect on VOCs chromatographic column case's main transmission line 21 from the sample of chromatographic column outflow through first transmission line. The main transmission pipeline comprises from inside to outside in sequence: stainless steel pipeline 34, frame type support pipe 35, heating layer 36 and heat preservation layer 37. Wherein the stainless steel pipeline is a stainless steel inerting pipeline and is used for connecting the chromatographic column and the four-way valve and transmitting a sample; the frame type supporting pipe is used for supporting the stainless steel pipeline and internally laying an inerting pipeline; the heating layer is wound on the frame type supporting pipe; and the heat insulation layer is wound on the periphery of the main transmission pipeline. The temperature control of the transmission pipeline adopts a closed loop control mode of thermocouple temperature measurement and direct current PWM heating.

Example 2 design of Low Heat Capacity Microchromatography column Box for semi-volatile organic Compounds

Example 2 differs from example 1 in that the low heat capacity mini chromatography column box of semi-volatile organic compounds (i.e. SVOCs chromatography column box) uses RTX-5 chromatography column, wherein the column length is 30m, the inner diameter is 0.25mm, the film thickness is 0.25um, the maximum heating temperature is 300 ℃, and the maximum temperature rise rate is 30 ℃/min.

Example 3 design of particulate phase organic Low Heat Capacity Microchromatography column Box

Example 2 differs from example 1 in that,

the particle phase organic matter low heat capacity micro chromatographic column box (OA chromatographic column box) adopts an RTX-5 chromatographic column, wherein the column length is 30m, the inner diameter is 0.25mm, the film thickness is 0.25um, the highest heating temperature is 350 ℃, and the maximum heating rate is 60 ℃/min.

Example 4

The volatile organic compound low heat capacity micro chromatographic column box (VOCs chromatographic column box) of example 1, the semi-volatile organic compound low heat capacity micro chromatographic column box (SVOCs chromatographic column box) of example 2 and the particle phase organic compound low heat capacity micro chromatographic column box (OA chromatographic column box) of example 3 are sequentially placed in a low heat capacity micro chromatographic column box system, a control circuit of the system adopts a double CPU structure, a CPU1 is a CPU with an MCS51 framework and is mainly used for temperature control (including heating and temperature control) of a sample transmission flow path, a fluid channel and a transmission channel; the CPU2 adopts an ARM-based CPU, and is mainly used for temperature control, valve box temperature control, and EPC pressure control of each low heat capacity micro-chromatography column box, and also can be used for start-stop control of a volatile organic compound enrichment and desorption pretreatment device, a semi-volatile organic compound enrichment and desorption pretreatment device, and a particle-phase organic compound enrichment and desorption pretreatment device. The CPU1 and the CPU2 communicate via I2C to transfer control and status information.

Example 5 Online measurement method of atmospheric organic matter

In the aging step (1): and sequentially carrying out carrier gas cleaning on the volatile organic matter enrichment and desorption pretreatment device 30, the semi-volatile organic matter enrichment and desorption pretreatment device 31, the particle-phase organic matter enrichment and desorption pretreatment device 32 and a transmission line thereof, and removing residual substances in the pipeline.

In the sampling step (2), volatile organic compounds in the atmospheric organic compounds are sequentially enriched in the volatile organic compound enrichment and desorption pretreatment device, semi-volatile organic compounds are enriched in the semi-volatile organic compound enrichment and desorption pretreatment device, and particle-phase organic compounds are enriched in the particle-phase organic compound enrichment and desorption pretreatment device.

In the purging step (3), the volatile organic compound enrichment and desorption pretreatment device 30, the semi-volatile organic compound enrichment and desorption pretreatment device 31, the particle-phase organic compound enrichment and desorption pretreatment device 32, and the transmission line thereof are sequentially subjected to carrier gas nitrogen purging to remove residual oxygen and other redundant interference gases.

The step (4) of sample injection comprises the following steps

Step i: and (3) the Volatile Organic Compounds (VOCs) enriched in the step (2) enter a VOCs chromatographic column box through a first fluid channel for separation, the separated Volatile Organic Compounds (VOCs) are collected to a main transmission pipeline of the VOCs chromatographic column box through a first transmission pipeline of the VOCs chromatographic column box, and then enter a mass spectrometer through a first transmission channel for measurement through a BC port of a first four-way valve 27 and a BC port of a second four-way valve 28, so that the sampling and analysis circulation of the volatile organic compounds is completed. At the moment, the pre-treatment device for enrichment and desorption of semi-volatile organic compounds is in a focusing mode, the pre-treatment device for enrichment and desorption of granular phase organic compounds is in a thermal desorption mode, and the RTX-5 chromatographic column in the SVOCs chromatographic column box and the RTX-5 chromatographic column in the OA chromatographic column box are both in an initial low-temperature mode;

step ii: and (3) after VOCs are measured, allowing the semi-volatile organic compounds (SVOCs) enriched in the step (2) to enter an SVOCs chromatographic column box through a second fluid channel for separation, collecting the SVOCs on a main transmission pipeline of the SVOCs chromatographic column box through a first transmission pipeline of the SVOCs chromatographic column box by the separated semi-volatile organic compounds (SVOCs), and allowing the SVOCs to enter a mass spectrometer through a first transmission channel for measurement through a DC port of a first four-way valve 27 and a BC port of a second four-way valve 28, so that a sampling and analyzing cycle of the semi-volatile organic compounds is completed. At the moment, the pre-treatment device for enrichment and desorption of volatile organic compounds is in an aging mode, the pre-treatment device for enrichment and desorption of granular phase organic compounds is in a thermal desorption mode, and the RTX-624 chromatographic column in the VOCs chromatographic column box and the RTX-5 chromatographic column in the OA chromatographic column box are both in a low-temperature standby mode;

step iii: and (3) after SVOCs measurement is finished, feeding the enriched particle phase organic matters (OA) in the step (2) into an OA chromatographic column box through a third fluid channel for separation, collecting the OA in a main transmission pipeline of the OA chromatographic column box through a first transmission pipeline of the OA chromatographic column box by the separated particle phase organic matters (OA), and then feeding the OA into a mass spectrometer through a first transmission pipeline through a DC port of a second four-way valve 28 for measurement, thus finishing one cycle of sampling and analyzing the particle phase organic matters. At this time, the volatile organic compound enrichment and desorption pretreatment device 30 and the semi-volatile organic compound enrichment and desorption pretreatment device 31 are both in a standby mode;

completing a sampling and analyzing cycle;

if the detection is needed to be continued, the steps are circulated.

Claims

1. A low heat capacity mini chromatography column cassette system comprising:

one or more than two low heat capacity micro chromatographic column boxes,

preferably, the volume of the box is 5cm x 5cm to 20cm x 10 cm.

2. The low heat capacity mini chromatography column cassette system of claim 1,

the heating unit is a resistance wire wound outside the chromatographic column;

3. The low heat capacity mini chromatography column cassette system of claim 1,

4. The low heat capacity mini chromatography column cassette system of claim 3,

preferably, the heat dissipation unit is a fan.

5. The low heat capacity mini chromatography column cassette system of claim 4,

6. The low heat capacity mini chromatography column cassette system of claim 5,

preferably, the main transfer line comprises:

a line for connecting a chromatography column;

a support pipe for supporting the stainless steel pipeline;

the heating layer is wound on the frame type supporting pipe;

7. An online measurement system for atmospheric organic compounds, comprising:

a low heat capacity micro-cartridge system of any of claims 1-6 connected to a pretreatment apparatus;

a mass spectrometer;

8. The on-line measuring system for atmospheric organics according to claim 7,

9. The on-line measuring system for atmospheric organics according to claim 8,

preferably, the second fluid passage and the third fluid passage each comprise:

a line for connecting a chromatography column;

a support pipe for supporting the stainless steel pipeline;

the heating layer is wound on the frame type supporting pipe;

the heat insulation layer is wound on the periphery of the fluid channel;

it is further preferred that the first and second liquid crystal compositions,

the heat-resistant temperature of the second fluid channel is 100-350 ℃;

the heat-resistant temperature of the third fluid channel is 100-350 ℃.

10. The on-line measuring system for atmospheric organics according to claim 9,

the first four-way valve is connected with the second four-way valve;

11. The online measurement method using the online measurement system for atmospheric organic compounds according to any one of claims 7 to 10, comprising:

preferably, the sampling step includes:

further preferably, the sample injection step comprises:

more preferably, the sample injection step comprises: