阅读说明：本技术 在线分析VOCs和SVOCs的装置及方法 (Device and method for analyzing VOCs and SVOCs on line ) 是由 朱锋 段炼 周伟峰 马乔 王海东 刘立鹏 韩双来 于 2020-12-30 设计创作，主要内容包括：本发明提供了在线分析VOCs和SVOCs的装置及方法,所述在线分析VOCs和SVOCs的装置包括检测器；第一吸附单元用于吸附待测样品中的VOCs和SVOCs；第二吸附单元用于吸附SVOCs；第一色谱柱用于VOCs的分离,第二色谱柱用于SVOCs的分离多通阀的端口分别连通所述第一吸附单元的出口、载气、第二吸附单元的两端、第一色谱柱和第二色谱柱；所述多通阀用于使所述第二吸附单元的一端选择性地连通载气和第一色谱柱,使所述第二吸附单元的另一端选择性地连通所述第一吸附单元的出口和所述第二色谱柱；温控单元用于加热和制冷所述第一吸附单元和第二吸附单元。本发明具有结构简单、检测准确度高等优点。(The invention provides a device and a method for analyzing VOCs and SVOCs on line, wherein the device for analyzing VOCs and SVOCs on line comprises a detector; the first adsorption unit is used for adsorbing VOCs and SVOCs in a sample to be detected; the second adsorption unit is used for adsorbing SVOCs; the first chromatographic column is used for separating VOCs, and the port of the separation multi-way valve of the second chromatographic column used for SVOCs is respectively communicated with the outlet of the first adsorption unit, the carrier gas, the two ends of the second adsorption unit, the first chromatographic column and the second chromatographic column; the multi-way valve is used for enabling one end of the second adsorption unit to be selectively communicated with the carrier gas and the first chromatographic column and enabling the other end of the second adsorption unit to be selectively communicated with the outlet of the first adsorption unit and the second chromatographic column; the temperature control unit is used for heating and refrigerating the first adsorption unit and the second adsorption unit. The invention has the advantages of simple structure, high detection accuracy and the like.)

1. The device for analyzing the VOCs and the SVOCs on line comprises a detector; characterized in that, the device for on-line analysis of VOCs and SVOCs further comprises:

the first adsorption unit is used for adsorbing VOCs and SVOCs in a sample to be detected;

a second adsorption unit for adsorbing SVOCs;

a first chromatographic column for separation of VOCs and a second chromatographic column for separation of SVOCs

The port of the multi-way valve is respectively communicated with the outlet of the first adsorption unit, the carrier gas, the two ends of the second adsorption unit, the first chromatographic column and the second chromatographic column; the multi-way valve is used for enabling one end of the second adsorption unit to be selectively communicated with the carrier gas and the first chromatographic column and enabling the other end of the second adsorption unit to be selectively communicated with the outlet of the first adsorption unit and the second chromatographic column;

and the temperature control unit is used for heating and refrigerating the first adsorption unit and the second adsorption unit.

2. The apparatus for online analysis of VOCs and SVOCs according to claim 1, further comprising:

and the switching module is used for enabling the inlet of the first adsorption unit to be selectively communicated with the sample to be detected and the carrier gas.

3. The apparatus for online analysis of VOCs and SVOCs according to claim 2, further comprising:

a sample buffer tube disposed between the switching module and the inlet of the first adsorption unit.

4. The apparatus of claim 1, wherein the first column is a PLOT column and the second column is a DB-1 column.

5. The apparatus of claim 1, wherein the first adsorption unit is filled with PDMS material.

6. The apparatus of claim 1 wherein the ports of the multi-way valve are further in communication with a sample to be tested and a pump, and the outlet of the first adsorption unit is selectively in communication with the sample to be tested.

7. A method for online analysis of VOCs and SVOCs, the method comprising the steps of:

(A1) the sample to be detected enters a first adsorption unit, and VOCs and SVOCs in the sample are adsorbed;

(A2) desorbing VOCs and SVOCs in the first adsorption unit;

(A3) the carrier gas carries VOCs and SVOCs desorbed from the first adsorption unit to enter a second adsorption unit, and the desorbed SVOCs are adsorbed in the second adsorption unit;

(A4) at least part of the desorbed VOCs passes through a second adsorption unit, then is sent to a first chromatographic column, and the separated components are sent to a detector;

(A5) desorbing the SVOCs in the second adsorption unit; and switching a flow path, allowing the carrier gas to carry the desorbed SVOCs in the second adsorption unit to enter a second chromatographic column, and allowing the separated components to enter the detector.

8. The method of claim 6, wherein the method of online analysis of VOCs and SVOCs further comprises the steps of:

(A0) selecting a first adsorption unit, a second adsorption unit and a first chromatographic column and a second chromatographic column which are matched with the VOCs and the SVOCs.

9. The method of claim 7, wherein in the first adsorption unit, VOCs and SVOCs are adsorbed using solid phase microextraction.

Technical Field

The present invention relates to the separation and detection of substances, and more particularly to an apparatus for on-line analysis of VOCs and SVOCs.

Background

The definition of HJ/T-2005 in China is as follows: at a standard pressure of 101.3kpa, the VOCs are widely present in air, water, soil and other media and comprise aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, aldehydes, ketones and other compounds as main components of any organic compound with an initial boiling point of 250 ℃ or lower. Semi-volatile organic compounds (SVOCs) mainly comprise dioxins, polycyclic aromatic hydrocarbons, organic pesticides, chlorobenzene, polychlorinated biphenyl, pyridine, quinoline, nitrobenzene, phthalate, nitrosoamine, aniline, phenol, polychlorinated naphthalene, polybrominated diphenyl ethers and other compounds.

The pretreatment method mainly comprises a solid adsorption thermal desorption method, a static headspace method, a purging and trapping method and a solid phase microextraction method, wherein the semi-volatile organic matters in the soil are extracted by adopting a liquid-liquid extraction method, in the pretreatment method, quartz fibers coated with an extraction stationary phase are directly inserted into a sample matrix, and target components are directly transferred from the sample matrix to the extraction stationary phase. For gas samples, natural convection of the gas is already sufficient to accelerate the equilibrium of the analytical components between the two phases. However, for water samples, the diffusion rate of the components in water is 3-4 orders of magnitude lower than that of gas, and therefore an effective blending technique is required to achieve rapid diffusion of the components in the sample.

The analysis method mainly adopts a gas chromatography or a gas chromatography-mass spectrometry combined method. In the analysis process of VOCs and SVOCs, whether the analysis process is a gas chromatograph or a gas chromatograph-mass spectrometer; both FID and mass spectrometry detectors are universal detectors capable of analyzing VOCs and SVOCs species simultaneously.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a detection device for a multi-component substance.

The purpose of the invention is realized by the following technical scheme:

the device for analyzing the VOCs and the SVOCs on line comprises a detector; the device for online analysis of VOCs and SVOCs further comprises:

the first adsorption unit is used for adsorbing VOCs and SVOCs in a sample to be detected;

a second adsorption unit for adsorbing SVOCs;

a first chromatographic column for separation of VOCs and a second chromatographic column for separation of SVOCs

The port of the multi-way valve is respectively communicated with the outlet of the first adsorption unit, the carrier gas, the two ends of the second adsorption unit, the first chromatographic column and the second chromatographic column; the multi-way valve is used for enabling one end of the second adsorption unit to be selectively communicated with the carrier gas and the first chromatographic column and enabling the other end of the second adsorption unit to be selectively communicated with the outlet of the first adsorption unit and the second chromatographic column;

and the temperature control unit is used for heating and refrigerating the first adsorption unit and the second adsorption unit.

The invention also aims to provide a method for analyzing VOCs and SVOCs on line, which is realized by the following technical scheme:

a method for online analysis of VOCs and SVOCs, the method comprising the steps of:

(A1) the sample to be detected enters a first adsorption unit, and VOCs and SVOCs in the sample are adsorbed;

(A2) desorbing VOCs and SVOCs in the first adsorption unit;

(A3) the carrier gas carries VOCs and SVOCs desorbed from the first adsorption unit to enter a second adsorption unit, and the desorbed SVOCs are adsorbed in the second adsorption unit;

(A4) at least part of the desorbed VOCs passes through a second adsorption unit, then is sent to a first chromatographic column, and the separated components are sent to a detector;

(A5) desorbing the SVOCs in the second adsorption unit; and switching a flow path, allowing the carrier gas to carry the desorbed SVOCs in the second adsorption unit to enter a second chromatographic column, and allowing the separated components to enter the detector.

Compared with the prior art, the invention has the beneficial effects that:

1. the structure is simple;

by using the cutting of the second adsorption unit, the one-step separation analysis of VOCs and SVOCs substances can be realized, and a proper chromatographic column is selected to achieve the optimal separation analysis effect and complete qualitative and quantitative analysis; therefore, only one set of device is needed, the chromatographic column does not need to be replaced, and multiple sample tests are not needed;

the adsorption of organic matters is completed through the adsorption of PDMS materials (carbon molecular sieves), and the online enrichment and separation analysis of the organic matters in water (gas) are realized;

2. the separation effect is good;

the second adsorption unit realizes the focusing of SVOCs substances, realizes non-shunting sample injection and achieves better separation degree and response value;

compared with direct analysis by using a thin-film chromatographic column, VOCs penetrate through the SVOCs focused by the second adsorption unit and enter the chromatographic column for separation and analysis, so that separation and analysis of VOCs are achieved, the separation degree of C3-C6 substances is greatly improved, and better qualitative and quantitative effects can be achieved;

through the selection of the kind of second adsorption unit and the selection of temperature, can realize the cutting of different carbon number VOCs material, also can reach the effect of cutting the solvent.

Drawings

The disclosure of the present invention will become more readily understood with reference to the accompanying drawings. As is readily understood by those skilled in the art: these drawings are only for illustrating the technical solutions of the present invention and are not intended to limit the scope of the present invention. In the figure:

FIG. 1 is a schematic diagram of the structure of an apparatus for on-line analysis of VOCs and SVOCs according to an embodiment of the present invention;

fig. 2 is another schematic structural diagram of an apparatus for on-line analysis of VOCs and SVOCs according to an embodiment of the present invention.

Detailed Description

Fig. 1-2 and the following description depict alternative embodiments of the invention to teach those skilled in the art how to make and reproduce the invention. Some conventional aspects have been simplified or omitted for the purpose of teaching the present invention. Those skilled in the art will appreciate that variations or substitutions from these embodiments will be within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention. Thus, the present invention is not limited to the following alternative embodiments, but is only limited by the claims and their equivalents.

Example 1:

fig. 1 is a schematic structural diagram of an apparatus for online analyzing VOCs and SVOCs according to an embodiment of the present invention, and as shown in fig. 1, the apparatus for online analyzing VOCs and SVOCs includes:

detectors, such as FID detectors;

the first adsorption unit 11 is used for adsorbing VOCs and SVOCs in a sample to be detected, for example, PDMS is used for adsorbing organic matters in water, and carbon molecular sieve-like adsorption materials are used for adsorbing organic matters in gas;

a second adsorption unit 12, wherein the second adsorption unit 12 is used for adsorbing SVOCs;

a first chromatographic column 31 and a second chromatographic column 32, the first chromatographic column 31 being used for separation of VOCs and the second chromatographic column 32 being used for separation of SVOCs;

utilize the selection of second adsorption unit and chromatographic column, realized the cutting effect of different types of VOCs and SVOCs:

1. and selecting a capillary hollow tube as a material for adsorbing the SVOCs, enabling VOCs with the boiling point of below 250 ℃ to pass through the second adsorption unit, entering a thick chromatographic column for separation and analysis, and desorbing by using the second adsorption unit module to realize the separation and analysis of the SVOCs.

2. And (3) selecting a low-polarity and thin-film-thickness capillary chromatographic column as a material for adsorbing SVOCs, wherein some VOCs (volatile organic compounds) of C8-C10 can be focused in the capillary column, and substances before C8 can enter the thick-film-thickness chromatographic column for separation and analysis, and then the second adsorption unit desorbs to realize separation and analysis of VOCs of C8-C10 and SVOCs.

3. And (3) selecting a high-polarity thick-film capillary chromatographic column as a material for adsorbing SVOCs, wherein some VOCs (volatile organic compounds) of C3-C10 can be focused in the capillary column, substances before C2-C3 can enter the thick-film chromatographic column (PLOT column) for separation and analysis, and then the second adsorption unit desorbs to realize the separation and analysis of VOCs of C3-C10 and SVOCs.

4. Through the selection of the type of the capillary column and the temperature of the second adsorption unit module, the cutting of organic matters with different carbon numbers can be effectively controlled, the low-boiling-point VOCs can penetrate through the second adsorption unit to complete separation analysis, and meanwhile, the second adsorption unit desorbs to complete separation analysis without separation.

A multi-way valve 21, the ports of which 21 are respectively communicated with the outlet of the first adsorption unit 11, the carrier gas, the two ends of the second adsorption unit 12, the first chromatographic column 31 and the second chromatographic column 32; the multi-way valve 21 is used for enabling one end of the second adsorption unit 12 to be selectively communicated with the carrier gas and the first chromatographic column 31, and enabling the other end of the second adsorption unit 12 to be selectively communicated with the outlet of the first adsorption unit 11 and the second chromatographic column 32;

and the temperature control unit is used for heating and refrigerating the first adsorption unit and the second adsorption unit so as to adsorb and collect at low temperature and desorb at high temperature.

In order for the apparatus to further comprise:

and the switching module is used for enabling the inlet of the first adsorption unit to be selectively communicated with the sample to be detected and the carrier gas.

The invention discloses a method for analyzing VOCs and SVOCs on line, which comprises the following steps:

(A1) a sample to be detected enters a first adsorption unit, and VOCs and SVOCs in the sample are adsorbed by using a solid-phase microextraction method;

(A2) desorbing VOCs and SVOCs in the first adsorption unit;

(A3) the carrier gas carries VOCs and SVOCs desorbed from the first adsorption unit to enter a second adsorption unit, and the desorbed SVOCs are adsorbed in the second adsorption unit;

(A4) at least part of the desorbed VOCs passes through a second adsorption unit, then is sent to a first chromatographic column, and the separated components are sent to a detector;

(A5) desorbing the SVOCs in the second adsorption unit; and switching a flow path, allowing the carrier gas to carry the desorbed SVOCs in the second adsorption unit to enter a second chromatographic column, and allowing the separated components to enter the detector.

Matching different detection objects, and the method for analyzing VOCs and SVOCs on line further comprises the following steps:

(A0) selecting a first adsorption unit, a second adsorption unit and a first chromatographic column and a second chromatographic column which are matched with the VOCs and the SVOCs.

Example 2:

the device and the method for online analysis of VOCs and SVOCs and the application example of the method in detection of organic matters in water according to embodiment 1 of the invention are disclosed.

In this application example, as shown in fig. 1, the multi-way valve 21 uses a ten-way valve, and the first adsorption unit 11 is filled with the PDMS material; the first column 31 was a PLOT column, and the second column 32 was a DB-1 column.

The invention discloses a method for analyzing VOCs and SVOCs on line, which comprises the following steps:

(A1) water enters a first adsorption unit, and VOCs and SVOCs in a sample are adsorbed by using a solid phase microextraction method;

(A2) desorbing VOCs and SVOCs in the first adsorption unit;

(A3) the multi-way valve is switched, so that one end of the second adsorption unit is communicated with the outlet of the first adsorption unit, and the first chromatographic column is communicated with the other end of the second adsorption unit;

the carrier gas carries VOCs and SVOCs desorbed from the first adsorption unit to enter a second adsorption unit, and the desorbed SVOCs are adsorbed in the second adsorption unit;

(A4) at least part of the desorbed VOCs passes through a second adsorption unit, then is sent to a first chromatographic column, and the separated components are sent to a detector;

(A5) desorbing the SVOCs in the second adsorption unit; switching the flow path so that one end of the second adsorption unit is communicated with the second chromatographic column and the carrier gas is communicated with the other end of the second adsorption unit;

and the carrier gas carries the desorbed SVOCs in the second adsorption unit to enter a second chromatographic column, and the separated components enter the detector.

Example 3:

the device and the method for online analyzing VOCs and SVOCs and the application example of the method in detecting organic matters in the atmosphere according to embodiment 1 of the invention are disclosed.

In this application example, as shown in fig. 2, the multi-way valve 22 uses a ten-way valve, and the ports communicate with the sampling pipe 51 and the sampling pump 61. The first adsorption unit 11 is filled with carbon molecular sieve-type adsorption materials to adsorb organic matters in the air, wherein the adsorption materials comprise a series of organic matters of C2-C20, wherein the low-carbon organic matters of C2-C3 are not easy to separate and analyze on a DB-1 chromatographic column, a PLOT column is used as the first chromatographic column 31, and a DB-1 column is used as the second chromatographic column 32.

The invention discloses a method for analyzing VOCs and SVOCs on line, which comprises the following steps:

(A0) selecting an adsorption unit and each chromatographic column according to the detection correspondence-air; the second adsorption unit selects a capillary column with larger polarity and a film thickness of 3-5 microns, the first adsorption unit is filled with carbon molecular sieve-type adsorption materials to adsorb organic matters in the air, wherein the first adsorption unit comprises a series of C2-C20 organic matters, the C2-C3-type low-carbon organic matters are not easy to separate and analyze on a DB-1 chromatographic column, the first chromatographic column adopts a PLOT column, and the second chromatographic column adopts a DB-1 column;

(A1) switching the multi-way valve to enable one end of the first adsorption unit to be communicated with the sampling pipeline and the other end of the first adsorption unit to be communicated with the sampling pump;

the sampling pump works to enable air to be detected to enter the first adsorption unit, and VOCs and SVOCs in the air are captured by the first adsorption unit;

(A2) switching the multi-way valve to enable one end of the first adsorption unit to be communicated with the carrier gas, the other end of the first adsorption unit to be communicated with one end of the second adsorption unit, and the other end of the second adsorption unit to be communicated with the first chromatographic column;

desorbing VOCs and SVOCs in the first adsorption unit;

(A3) the carrier gas carries VOCs and SVOCs desorbed from the first adsorption unit to enter a second adsorption unit, and the desorbed SVOCs-C6-C30 substances are adsorbed in the second adsorption unit;

(A4) at least part of the desorbed VOCs of C2-C5 passes through a second adsorption unit, and then is sent to a first chromatographic column, and the separated components are sent to a detector;

(A5) desorbing the SVOCs in the second adsorption unit; and switching the flow path, allowing the carrier gas to carry the SVOCs-C6-C30 matters desorbed from the second adsorption unit into the second chromatographic column, and allowing the separated components to enter the detector.