HK1172149B - Sampling device for ion migration spectrometer and method for using the same, and ion migration spectrometer - Google Patents

Description

Sample introduction device for ion mobility spectrometer, use method of sample introduction device and ion mobility spectrometer

Technical Field

The invention relates to the technical field of ion mobility detection, in particular to a sample introduction device for an ion mobility spectrometer and a method for detecting solid particles and gas samples to be detected by using the sample introduction device. In addition, the invention also relates to an ion mobility spectrometer with the sample feeding device.

Background

The detector based on the Ion Mobility Spectrometry (IMS) technology can be used for detecting trace-level explosives, drugs, chemical poisons and other contraband articles, and is widely applied to the fields of military affairs and security inspection at present due to the characteristics of rapidness, sensitivity, portability, operation and the like. Most commercial portable ion mobility spectrometry devices have two sampling methods, solid or wiped sampling and gas sampling: the former uses clean sampling carrier such as paper to wipe the suspicious surface, collects the particles of the object to be tested, then puts the paper or carrier adhered with the particles into the inlet of the instrument, and gasifies the solid explosive for analysis by thermal desorption. In the sampling and testing process, an operator needs to wear gloves or use a specially designed wiping sampler provided with a sampling carrier so as to avoid polluting the sampling carrier and detection equipment; the latter uses the air pump to directly suck the vapor sample on the atmosphere or solid surface to be measured into the sample feeding device of the instrument for analysis.

The gas sampling method is simple to operate, does not need consumables, and can avoid direct contact with the object to be detected, but because the vapor pressure of most objects to be detected, such as explosives and narcotics, is very low (below ppb), the lower limit value of the detection of the instrument is difficult to achieve by only directly sucking the sample in the collection mode. If a pre-concentration or enrichment device is arranged at the front end of the analysis system, the detection capability of the instrument can be greatly improved. The preconcentrator mainly comprises an adsorbing material and a heater, and the working principle of the preconcentrator is that firstly, gas to be detected is enriched through the adsorbing material, and the adsorbing material is heated after a period of time so that the adsorbed gas is analyzed in a short time, so that higher gas concentration is obtained. Some commercial instruments, such as the VaporTracer of GE, use an external portable vacuum aspirator to collect a gas sample, first place the sampling carrier in the air intake of a vacuum device, so that the air containing the analyte vapor passes through the sampling carrier for a period of time, then capture the analyte molecules thereon, then place the sampling medium in a detector, and release the analyte molecules for analysis by thermal desorption, thus the device actually plays a role in sample enrichment.

There are several related patents that describe pre-concentration devices for ion mobility spectrometers or other similar analytical instruments. Patent US5162652 describes a sample mix-concentration introduction technique in which a portion of the gas in a sealed bag is extracted and combined with ambient atmosphere in a closed chamber, the mixed sample is passed through a collector to concentrate certain molecules to be detected on a collection surface, and the adsorbed molecules are subsequently released from the surface and sent to an ion mobility spectrometer for analysis; patent US6604406 describes a manually transportable preconcentration device, through a permeable screen, capturing the target substances and releasing them into the chamber by heating; the patent US5083019 describes an adsorption probe concentrating device, wherein an adsorption probe prepared by a metal wire coil with an adsorption coating on the surface is placed in a sample injection airflow at low temperature, a gas sample is collected by the surface of the adsorption probe, and the adsorption probe is manually fed into an ionization reaction area of an ion migration device through a sliding shaft in the test process and then is rapidly heated, so that a substance to be detected is desorbed and is ionized; patent WO2007091998 describes a solid phase microextraction optical fiber collection and concentration technique, which adopts a solid phase microextraction optical fiber exposed in the air to collect a sample of explosive, taggant or a mixture thereof, puts the optical fiber into a preconcentration device after the thermal desorption action to concentrate the sample, and makes the sample enter an ion mobility spectrometer for detection. Patent US20090249958 describes a device assembly with replaceable concentration carriers, consisting of a housing and an internal housing, forming a cavity for accommodating a plurality of concentration carriers and a passage leading to a sample introduction device of a detection instrument by means of a retractable spring hold-down device, so that a continuous gas flow can bring the substances collected by the concentration carriers into the instrument for analysis; the concentration device related in patent WO2008074981 is located in an ion migration sample injection device, and a pulse pressure generator connected with a migration tube cavity alternately applies small negative pressure and positive pressure to the tube cavity to suck or discharge air into or out of the sample injection device in a way of simulating wheezing, so that a component to be measured cannot enter an ionization region and is effectively adsorbed by the preconcentration device, after the component to be measured is accumulated for a period of time, the pressure generator generates a large negative pressure to suck an object to be measured released by the preconcentration device into the ionization region inside an instrument for analysis; the preconcentration device described in patent WO2007113486 is connected to the inlet of an ion mobility spectrometer and is formed by a metal tube having a layer of silica gel adsorbing material on the inner surface, and a resistance heating element connected to a power supply is arranged below the adsorbing layer for periodically heating the silica gel adsorbing layer to desorb adsorbed substances and release the substances into the ion mobility spectrometer at a higher concentration.

In practical use, because solid wiping sampling is still a sample collection mode conventionally used by the existing ion migration equipment, a sampling carrier sample introduction device and a thermal analyzer for heating a carrier are additionally arranged at the front end of the instrument. In order not to affect the solid sample injection device and function of the instrument, the concentrator described in the above-mentioned patent (for example, US5162652, US6604406, WO2007091998, US20090249958, etc.) generally adopts an external design, needs a separate device independent of the instrument, and samples are injected in the same way as solid sampling after sample collection is completed, so that the whole detection operation process is complicated and complicated; on the other hand, in an ion mobility spectrometry apparatus having a built-in concentrator (e.g., WO2008074981, WO2007113486, etc.), since an adsorption element in the concentrator needs to operate at a low temperature, a thermal analyzer is not provided at the front end of the apparatus, so that the apparatus can be used only for analysis of a gas sample.

Therefore, there is a need to develop a more practical ion mobility spectrometry device, which has both the functions of solid sampling and gas sampling, on one hand, it has a built-in concentration device to simplify the configuration and operation procedure of the device, and on the other hand, it can perform sensitive and convenient detection on the trace solid residue and the atmosphere with extremely low concentration of the analyte.

Disclosure of Invention

In view of the above, an object of the present invention is to solve at least one of the above problems and disadvantages in the prior art.

Accordingly, in view of the above-mentioned shortcomings existing in the design of the existing ion mobility spectrometry trace analysis equipment capable of detecting a gas sample, an object of the present invention is to provide a design and a use method of a novel sample introduction device of an ion mobility spectrometer, which integrates the functions of solid particle sample analysis and low concentration gas analysis into a single instrument, thereby being capable of taking into account the functions of solid sampling and gas sampling through the same sampling device.

Another objective of the present invention is to provide a design and usage method of a sample introduction device of a novel ion mobility spectrometer, which does not need to additionally provide a gas sample collection and concentration device, so as to simplify the operation procedure, improve the sensitivity and analysis efficiency of the gas sample, and simultaneously realize effective detection of the trace amount of solid sample.

According to one aspect of the present invention, there is provided a sample introduction device for an ion mobility spectrometer for introducing a sample to be tested into an inlet of a mobility tube of the ion mobility spectrometer, the sample introduction device comprising: an inner sleeve member defining an inner cavity therein, one end of the inner sleeve member communicating with the inlet of the migration tube through an inner passage, the other end of the inner sleeve member being provided with an inner end cap having an inner opening; and an outer sleeve member disposed as an eccentric sleeve coaxial with the inner sleeve member and rotatable with respect to the inner sleeve member to form a sleeve cavity between the inner and outer sleeve members, one end of which is provided with at least one communication opening selectively communicating with the inner layer passage, and the other end of which is provided with an outer end cap on which a first outer opening selectively communicating with the inner opening and a second outer opening communicating with the sleeve cavity are disposed, wherein the outer end cap is disposed rotatably with respect to the inner end cap between a first position and a second position to selectively introduce a sample to be measured into the inner layer passage through one of the inner cavity and the sleeve cavity.

In the above embodiment, when the outer end cap is disposed in the first position with respect to the inner end cap, the first outer opening on the outer end cap communicates with the inner opening on the inner end cap, the communication opening does not communicate with the inner layer channel, and the sample to be measured is introduced into the inner layer channel through the inner cavity; when the outer end cover is arranged to be in a second position relative to the inner end cover, the first outer opening on the outer end cover is not communicated with the inner opening on the inner end cover, the second outer opening on the outer end cover is communicated with the sleeve cavity, the communication opening is communicated with the inner layer channel, and a sample to be detected is guided into the inner layer channel through the sleeve cavity.

Preferably, a heating component is arranged outside the inner sleeve component and used for heating the inner cavity to form a thermal desorption cavity, and in the thermal desorption cavity, the solid sample to be detected is heated to form a gaseous sample to be detected.

Preferably, the heating member is further provided with a heat insulating layer on the outside thereof to form a thermal insulation between the inner sleeve member and the outer sleeve member.

Specifically, the inner opening is formed in one side, close to the circle center, of the inner end cover; and the first outer opening is arranged on one side of the outer end cover close to the position of the circle center, and the second outer opening is arranged on the other side of the outer end cover far away from the circle center opposite to the first outer opening.

More specifically, the inner opening and the first outer opening are square holes, and the second outer opening includes a plurality of round holes.

In one embodiment, the sample introduction device for an ion mobility spectrometer further comprises: a semi-permeable membrane disposed between the inlet of the transfer tube and the inner channel for selectively permeating gaseous test substance introduced into the transfer tube.

Further, the sample injection device for the ion mobility spectrometer further comprises: the enrichment body is arranged between the semipermeable membrane and the inner layer channel and is close to the position of the semipermeable membrane, and is used for pre-concentrating the substance to be measured entering the inner layer channel.

In particular, the concentrate is constituted by a plurality of layers of enrichment sheets superimposed on each other, each of said plurality of layers of enrichment sheets comprising: a main body composed of a metal film or a screen having micropores on the surface thereof; and an adsorbent attached to the surface of the body to adsorb the substance to be measured.

More specifically, the micropores in the plurality of superposed enrichment sheets are staggered with respect to each other so as to increase the contact area between the sample gas flow and the adsorbent in the enrichment sheets when the gas vertically passes through the enrichment body.

More specifically, the apparatus further comprises a pulse heating device connected to said concentrate for controlled pulse heating of said concentrate.

According to another aspect of the present invention, there is provided a method for introducing a solid sample to be tested by using the sample introduction device for an ion mobility spectrometer, comprising the steps of: starting a heating part arranged outside the inner sleeve part, and continuously heating the inner cavity in the operation process to form a thermal resolution cavity; rotating the outer end cap such that the outer end cap is disposed in the first position relative to the inner end cap; introducing a solid sample to be tested into the thermal analysis cavity through the first outer opening on the outer end cover and the inner opening on the inner end cover, wherein the solid sample to be tested is heated in the thermal analysis cavity to form a gaseous sample to be tested; and introducing a gaseous sample to be tested into the inlet of the migration tube through the inner-layer channel.

According to another aspect of the present invention, there is provided a method for introducing a gas sample to be tested by using the above sample introduction device for an ion mobility spectrometer, comprising the steps of: starting a heating part arranged outside the inner sleeve part, and continuously heating the inner cavity in the operation process to form a thermal resolution cavity; rotating the outer end cap such that the outer end cap is disposed in the second position relative to the inner end cap; introducing a gas sample to be detected into an inner layer channel through a second outer opening on the outer end cover and a sleeve cavity, and pre-concentrating on the enrichment body; after the gas sample to be measured is pre-concentrated on the enrichment body for a preset time, rotating the outer end cover so that the outer end cover is arranged to be in the first position relative to the inner end cover; introducing airflow onto the concentrate through the thermal desorption cavity, and simultaneously exciting a pulse heating device connected with the concentrate so as to desorb a sample to be detected pre-concentrated on the concentrate to form a gaseous sample to be detected; and introducing a gaseous test sample into the inlet of the transfer tube.

According to yet another aspect of the present invention, there is provided an ion mobility meter comprising: a migration tube for performing ionization and migration operations on a sample to be tested introduced therein, wherein the migration tube comprises: an ionization region in which sample molecules to be measured are ionized to form an ion cluster; and a migration zone where the ion clusters complete the directional migration and separation process; gas path means for supplying a carrier gas to the ionization region and a migration gas to the migration region; and a sample introduction device as described above for introducing a sample to be tested into the inlet of the migration tube.

In the above technical solution, the ion mobility spectrometer further includes: and the sample injection pump is used for providing negative pressure to introduce the gas sample to be detected into the sample injection device.

Specifically, the migration tube includes: an ionization region in which sample molecules to be measured are ionized to form an ion cluster; and a migration zone where the ion clusters complete the directional migration and separation process.

The above-described unspecified embodiments of the present invention have at least the following advantages and effects in one or more of the following aspects:

1. the invention adopts the structural design of the inner sleeve and the outer sleeve, so that the inner sleeve and the outer sleeve can be switched between two different positions, thereby selectively providing two different air flow passages. Through adopting above-mentioned scheme, it integrates in single instrument with solid particle sample analysis and low concentration gas analysis function to can compromise the function of solid sampling and gas sampling through same sampling device.

2. In addition, in one embodiment of the invention, an external gas sample collecting and concentrating device is not required, so that the operation procedure can be simplified, the sensitivity and the analysis efficiency of the gas sample can be improved, and the effective detection of the trace solid sample can be realized at the same time. Specifically, in the embodiment of the invention, the enrichment carrier is arranged at the position adjacent to the semipermeable membrane in the sample injection device, the sample injection end adopts a unique sleeve type structural design with a spiral cover, and the low-temperature adsorption and the rapid temperature rise desorption of the enrichment carrier on the gas sample are realized by fully utilizing the heat source of the solid sample injection device by controlling the gas inlet channel under the condition of not influencing the solid sample injection function of the instrument, so that the effective preconcentration effect is realized, the instrument has the functions of analyzing the trace solid particle sample and the extremely-low-concentration gas sample, and a separate gas acquisition and concentration device is not required to be additionally arranged, the configuration and the operation procedure of the instrument are simplified, and the analysis efficiency of the instrument on the gas sample can be greatly improved.

3. In addition, in the invention, the enrichment carrier is arranged at the position adjacent to the semipermeable membrane in the sample feeding device, and the object to be detected released in the desorption process can quickly reach the surface of the membrane to complete the selective permeation process, thereby avoiding the loss of the sample in the airflow channel caused by adsorption or condensation deposition and further improving the sensitivity of the instrument.

Drawings

FIG. 1 is a schematic diagram of the composition and principle of an ion mobility spectrometer according to an embodiment of the present invention;

FIG. 2 is a schematic diagram showing the structure of a sample introduction device for an ion mobility spectrometer according to an embodiment of the present invention, wherein FIG. 2A is a schematic diagram showing a solid particle sample being introduced into the sample introduction device, and FIG. 2B is a schematic diagram showing a gas sample being introduced into the sample introduction device; and

fig. 3 is a schematic diagram showing the concentrate for an ion mobility spectrometer according to an embodiment of the present invention.

Detailed Description

The technical scheme of the invention is further specifically described by the following embodiments and the accompanying drawings 1-3. In the specification, the same or similar reference numerals denote the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the general inventive concept of the present invention and should not be construed as limiting the invention.

FIG. 1 is a schematic diagram of the composition and principle of an ion mobility spectrometer according to an embodiment of the present invention. As shown in fig. 1, an ion mobility spectrometer 1 according to the present invention includes: the migration tube 4 is used for ionizing and migrating the sample to be detected introduced into the migration tube; and a sample introduction device 2 having a sample introduction port for introducing a sample to be measured, which can introduce the sample to be measured into the migration tube 4 by sucking an air sample containing an atmosphere of the object to be measured or inserting a sampling carrier in which a solid particle sample is collected. The sample introduction device 2 is provided with a semi-permeable membrane 3 with selective permeability near the inlet 41 of the migration tube 4, which separates the interior of the ion mobility spectrometer from the sample introduction device 2 communicating with the external environment.

Referring to fig. 1, the ion mobility spectrometer further comprises a sample injection pump 10 for providing a negative pressure to introduce a gas sample to be measured into the sample injection device 2. Gaseous testee material molecule that advances the appearance mode and is introduced by sampling device 2 through solid particle or gas under the effect of sampling pump 10, is taken to pellicle 3 by the air current before, through pellicle 3's screening effect, gets into the core element ion migration pipe 4 in the ion mobility spectrometer 1, and the component that fails to see through pellicle 3 then discharges under the effect of sampling pump 10.

The transfer tube 4 is divided into two parts of an ionization reaction zone 6 and a transfer zone 7 by an ion gate 5 which can be opened periodically. The sample molecules to be detected are ionized in the ionization region to form ion clusters, and the ion clusters formed by ionization complete the directional migration and separation processes in the migration region. A uniformly distributed electric field is provided in the transition region 7 by applying a voltage to the annular electrode sheet 8. In the ionization region 5 of the ion migration tube 4, the molecules of the object to be measured are ionized and form ion clusters, and when the ion gate 5 is opened, the ion clusters enter the migration region 7 under the action of the electric field and continue to migrate and advance under the action of the electric field. In the migration region 7, the migration velocity of the ion clusters is related to the mass, the number of charges charged, the volume size, and the like, and therefore the arrival times of different ion clusters at the detector 9 located at the end of the migration region are different from each other, and the species of the substance can be determined by detecting the weak pulse current from the detector and the arrival time thereof and matching the same with the standard substance library.

In addition, the ion mobility spectrometer 1 includes: and the gas path device is used for supplying the carrier gas to the ionization area and supplying the migration gas to the migration area. The direction of the migration gas flow introduced from the back end of the instrument is opposite to the moving direction of ions, the migration gas flow is led out from the ionization chamber at a position close to the ion gate 5, under the pushing action of the circulating gas pump 11, the part of the gas purified and dried by the filter 12 is used as the migration gas flow S1 to enter the back part of the migration area, and the other part of the gas flow S2 forms a carrier gas path from the gas path containing the dopant source 13 to enter the ionization reaction area 6.

The structure and principle of the sample introduction device for an ion mobility spectrometer according to an embodiment of the present invention will be briefly described with reference to fig. 2A-2B.

Fig. 2 shows a sample introduction device 2 for an ion mobility spectrometer according to an embodiment of the present invention, which is used for introducing a sample to be tested into an inlet 41 of a migration tube 4 of the ion mobility spectrometer 1, and comprises: an inner sleeve member 21 defining an inner cavity 23 in its interior, one end of which communicates with the inlet 41 of the migration tube 4 through an inner passage 24, and the other end of which is provided with an inner end cap 25 having an inner opening 31; and an outer sleeve member 22 provided as an eccentric sleeve coaxial with the inner sleeve member 21 and rotatable with respect to the inner sleeve member 21 to form a sleeve cavity 26 between the inner and outer sleeve members 22, 21, one end of which is provided with at least one communication opening 27 selectively communicating with the inner passage 24, and the other end of which is provided with an outer end cap 28 on which a first outer opening 32 selectively communicating with the inner opening 31 and a second outer opening 33 communicating with the sleeve cavity 26 are provided, wherein the outer end cap 28 is provided to be rotatable with respect to the inner end cap 25 between a first position (a position shown in fig. 2A) and a second position (a position shown in fig. 2B) to selectively introduce a sample to be tested into the inner passage 24 through one of the inner cavity 23 and the sleeve cavity 26. As shown in fig. 2, the inner layer passage 24 includes a branch passage 24a communicating with the inner cavity 23 and a branch passage 24b communicating with the sleeve cavity 26 through a communication opening 27.

Referring to fig. 2, the inner sleeve member 21 is provided at the outside thereof with a heating member 29 for heating the inner chamber 23 to form a thermal desorption chamber in which a solid sample to be measured is heated to form a gaseous sample to be measured. A common example is a flat sample injection device made of a metal material such as stainless steel, which is externally wound with a heating wire to form a thermal desorption chamber. And keeping the sample feeding device at a high temperature by a continuous heating mode so as to heat and analyze or gasify the solid sample particles collected on the sampling carrier. The inner sleeve part 21 is provided with an inner passage 24 inside, and an air flow is introduced into the ion mobility spectrometer 1 from the sample introduction device 2 by the sample introduction pump 10.

In the above embodiment, the heating member is further provided with a heat insulating layer 30 on the outside thereof to provide thermal isolation between the inner cavity 23 and the sleeve cavity 26. Thus, the sample introduction device is divided into inner and outer layers having different temperatures, the inner layer being an inner cavity 23 surrounded by the inner sleeve member 21 and communicating with the branch passage 24 a. The outer layer is a sleeve cavity 26 formed by the inner sleeve member 21 and the outer sleeve member 22 coaxial with the inner sleeve member 21, which selectively communicates with the branch passage 24b through the communication opening 27.

In the above-described embodiments of the present invention, it forms a mechanism that can control or alter the entry of the gas sample into the inner channel 24. A typical example is shown in fig. 2: the inner opening 31 is provided on the inner cover 25 on a side thereof adjacent to the center of the circle. The outer sleeve is in the form of an eccentric sleeve coaxial with the inner sleeve and, correspondingly, the end cap is in the form of an eccentric circle, and the outer end cap 28 has a plurality of asymmetric openings, wherein a first outer opening 32 is provided adjacent the central location and is shaped to substantially coincide with the inner sample injection means, and the remaining openings 33 are distributed at peripheral locations and are in communication with the sleeve cavity 26, and a plurality of communication openings 27 are provided in the sleeve cavity for selective communication with the inner channel 24, and the positions of the first, second and communication openings 27 at the ends of the outer sleeve member can be changed by rotating the outer sleeve member. Referring to fig. 2, the first outer opening 32 is arranged on one side of the outer end cover 28 near the circle center position, and the shape of the first outer opening is completely overlapped with that of the inner layer sample injection device; a second outer opening 33, such as a plurality of circular holes, is distributed at a peripheral location, such as on the opposite side of the outer end cap 28 from the first opening 32 and communicates with the sleeve cavity 26. Although in fig. 2 the inner and first outer openings are square shaped apertures and the second outer opening 33 comprises a plurality of circular apertures, the invention is not so limited and may take any other suitable shape, for example.

Referring to fig. 2, when the outer end cap 28 is disposed in the first position of fig. 2A relative to the inner end cap 25 for solid particle sampling, the first outer opening 32 of the outer end cap 28 adjacent the center is rotated to a position completely coincident with the inner opening 31 of the inner end cap 25, the first outer opening 32 of the outer end cap 28 is in communication with the inner opening 31 of the inner end cap 25, the communication opening 27 is not in communication with the eccentric sleeve cavity 26, and the sample to be measured is introduced into the inner layer channel 24 through the inner cavity 23; when the outer end cap 28 is positioned in the second position of fig. 2B relative to the inner end cap 25 for gas sampling, the outer sleeve member is rotated so that the first outer central opening 32 of its end is rotated to the opposite side of the inner end cap 25, the first outer opening 32 of the outer end cap 28 is not in communication with the inner opening 31 of the inner end cap 25, and the eccentric sleeve cavity 26 is now in communication with the inner passage 24 through the plurality of openings 27, such that gas from the sleeve cavity 26 enters the inner passage 24.

Rotation of the inner and outer end caps 25, 28 may be accomplished manually or automatically by a control circuit. An enrichment carrier 14 is provided between the inner channel 24 and the semipermeable membrane 3 in proximity to the semipermeable membrane 3 for preconcentrating the substance to be introduced into the migration tube. Specifically, referring to fig. 3, the concentrate 14 is composed of a plurality of enrichment sheet layers 140 stacked on one another, each of the plurality of enrichment sheet layers 140 including: a body 141 made of a metal thin film or a mesh having micropores on the surface thereof; and an adsorbent attached to the surface of the body 141 to adsorb a substance to be detected. The metal is generally stainless steel, and the carrier is attached with an adsorbing substance such as active carbon powder or coated with an adsorbent having an adsorbing effect on the substance to be detected. Different designs can be adopted to ensure that the enrichment carrier has larger adsorption area, such as being folded into a wave shape, and micropores arranged on the surface of each layer of carrier are arranged in a staggered way, when gas vertically flows through the carrier layer, the gas can flow along the area between the pores on the surface of the carrier, thereby improving the contact area between the sample gas flow and the adsorbent on the collection surface of the carrier. In one embodiment, the apparatus further comprises a pulse heating device (not shown) connected to said concentrate 14, whereby said concentrate 14 may be controllably pulsed heated by operation of the pulse heating device.

The specific operation of sampling solid particles and sampling gas by using the sample injection device is described below with reference to the accompanying drawings:

a heating member 29, which is arranged outside the inner sleeve member, is activated before the sampling operation for continuously heating the inner cavity 23 during the operation to form a heat-resolving cavity. When a solid particle sample is taken, as shown in FIG. 2A, the outer end cap 28 is rotated such that the outer end cap 28 is disposed in a first position shown in FIG. 2A relative to the inner end cap; introducing a solid sample to be tested into a thermal desorption cavity through a first outer opening 32 on the outer end cover 28 and an inner opening 31 on the inner end cover 25, wherein the solid sample to be tested is heated to form a gaseous sample to be tested in the thermal desorption cavity; the gaseous sample to be tested is introduced into the inlet 41 of the transfer tube 4 through the inner passage 24.

When gas sampling is performed, as shown in fig. 2B, the outer end cap 28 is rotated so that the outer end cap 28 is disposed in the second position shown in fig. 2B with respect to the inner end cap 25; introducing a gas sample to be tested into the inner layer channel 24 through the second outer opening 32 on the outer end cover 28 and the sleeve cavity 26, and pre-concentrating on the enrichment body 14; after the pre-concentration of the gas sample to be measured on the enriched body 14 has been carried out for a predetermined time, rotating the outer end cap 28 so that the outer end cap 28 is disposed in the first position shown in fig. 2A with respect to the inner end cap 25; introducing the gas flow onto the concentrate 14 through a thermal desorption chamber, and selectively exciting a pulse heating device connected with the concentrate to gasify and desorb a sample to be tested pre-concentrated on the concentrate 14; and introducing the gaseous sample to be tested into the inlet 41 of the migration tube 4 through the inner passage 24.

In actual detection, the thermal desorption cavity 23 of the sample introduction device of the ion mobility spectrometer 1 is always in a continuously heated state, when solid sampling is performed, the outer sleeve part 22 of the sample introduction device 2 is rotated to the first position shown in fig. 2A, so that the opening 32 of the end part adjacent to the center is communicated with the inner opening 31 of the inner end cover 25, the communicating inner hole 27 is not communicated with the sleeve cavity 26, and gas enters the interior of the ion mobility spectrometer 1 from the thermal desorption cavity 23. The solid sampling carrier is inserted into the sample injection device 2 through the inner and outer openings 31 and 32, and the solid particle sample collected by the carrier is gasified and enters the ion mobility spectrometer 1 along with the air flow for analysis.

When the ion mobility spectrometer 1 is to sample gas, the outer sleeve member 22 is first rotated to the second position shown in fig. 2B such that the opening 32 in the outer end cap 28 adjacent the center is rotated to the opposite side of the inner opening 31 in the inner end cap 25 and the communicating inner bore 27 is in communication with the sleeve cavity 26, and gas is drawn from the sleeve cavity 26 into the inner passage 24. Because the heat insulating layer is arranged between the sleeve cavity 26 and the thermal desorption cavity 23, the temperature of the gas introduced into the inner layer channel 24 from the sleeve cavity 26 is close to the ambient temperature, and the temperature is still lower when the gas flows through the enrichment carrier 14, so that the gas sample is favorably and effectively adsorbed; after a period of collection, the outer sleeve member 22 is rotated to the first position shown in fig. 2A, which corresponds to the position where solid particles are sampled, and gas enters the ion mobility spectrometer 1 from the thermal desorption chamber 23 under the action of the sample pump 10.

At this time, since the gas flow passes through the high-temperature thermal desorption cavity 23, the temperature is rapidly increased, and when the gas flow passes through the enrichment carrier 14, the enrichment carrier 14 made of a metal material is heated, and simultaneously, the pulse heating function of the enrichment carrier 14 can be activated, so that the temperature of the carrier is rapidly increased to release the adsorbed substance to be detected. The gas resistance on the gas flow path is small during gas collection, the gas flow is large during sample collection or adsorption, more atmosphere of the object to be detected can be inhaled, the gas flow path is narrow during desorption, the flow is small, and the adsorbed components are released into the small-flow gas flow, so that the concentration effect is enhanced. In addition, because the enrichment carrier 14 is arranged at a position close to the semipermeable membrane 3, the object to be detected released in the desorption process can quickly reach the surface of the semipermeable membrane 3 to complete the selective permeation process, thereby avoiding the loss of the sample in the airflow channel caused by adsorption or condensation deposition and further improving the sensitivity of the ion mobility spectrometer 1.

Although a few embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.

Claims (16)

1. A sample introduction device for an ion mobility spectrometer for introducing a sample to be measured into an inlet of a mobility tube of the ion mobility spectrometer, the sample introduction device comprising:

an inner sleeve member defining an inner cavity therein, one end of the inner sleeve member communicating with the inlet of the migration tube through an inner passage, the other end of the inner sleeve member being provided with an inner end cap having an inner opening; and

an outer sleeve member provided as an eccentric sleeve coaxial with the inner sleeve member and rotatable relative to the inner sleeve member to form a sleeve cavity between the inner and outer sleeve members, one end of which is provided with at least one communication opening selectively communicating with the inner layer passage and the other end of which is provided with an outer end cap on which a first outer opening selectively communicating with the inner opening and a second outer opening communicating with the sleeve cavity are provided,

wherein the outer end cap is configured to be rotatable relative to the inner end cap between a first position and a second position to selectively direct a sample to be tested into the inner channel through one of the inner cavity and the sleeve cavity.

2. The sample introduction device for an ion mobility spectrometer of claim 1, wherein:

when the outer end cover is arranged at a first position relative to the inner end cover, a first outer opening on the outer end cover is communicated with an inner opening on the inner end cover, the communication opening is not communicated with the inner-layer channel, and the sample to be detected is introduced into the inner-layer channel through the inner cavity;

when the outer end cover is arranged to be in a second position relative to the inner end cover, the first outer opening on the outer end cover is not communicated with the inner opening on the inner end cover, the second outer opening on the outer end cover is communicated with the sleeve cavity, the communication opening is communicated with the inner layer channel, and a sample to be detected is guided into the inner layer channel through the sleeve cavity.

3. The sample introduction device for an ion mobility spectrometer according to claim 1 or 2, wherein:

the outer portion of inner sleeve part is provided with the heater block, is used for right interior cavity heats in order to form the thermal analysis cavity in the thermal analysis cavity, solid-state sample that awaits measuring is heated in order to form gaseous sample that awaits measuring.

4. The sample introduction device for an ion mobility spectrometer of claim 3, wherein:

the heating component is also provided with a heat insulating layer outside so as to form heat insulation between the inner sleeve and the outer sleeve.

5. The sample introduction device for an ion mobility spectrometer of claim 3, wherein:

the inner opening is formed in one side, close to the circle center, of the inner end cover; and

the first outer opening is arranged on one side, close to the position of the circle center, of the outer end cover, and the second outer opening is arranged on the other side, far away from the circle center, of the outer end cover, opposite to the first outer opening.

6. The sample introduction device for an ion mobility spectrometer of claim 5, wherein:

the interior trompil with first outer trompil is the quad slit, the outer trompil of second includes a plurality of round holes.

7. The sample introduction device for an ion mobility spectrometer of claim 4, further comprising:

a semi-permeable membrane disposed between the inlet of the transfer tube and the inner passage for filtering gaseous species introduced into the transfer tube.

8. The sample introduction device for an ion mobility spectrometer of claim 7, further comprising:

the enrichment body is arranged between the semipermeable membrane and the inner layer channel and is close to the position of the semipermeable membrane, and is used for pre-concentrating the substance to be measured entering the inner layer channel.

9. The sample introduction device for an ion mobility spectrometer of claim 8, wherein:

the concentrate is comprised of a plurality of enrichment sheet layers stacked on top of each other, each of the plurality of enrichment sheet layers comprising:

a main body composed of a metal thin film having micropores on a surface thereof; and an adsorbent attached to the surface of the body to adsorb the substance to be measured.

10. The sample introduction device for an ion mobility spectrometer of claim 9, further comprising:

a pulse heating means connected to said concentrate for controlled pulse heating of said concentrate.

11. The sample introduction device for an ion mobility spectrometer of claim 9, wherein:

the pores in the plurality of superposed enrichment sheets are staggered with respect to each other to increase the contact area between the sample gas flow and the adsorbent in the enrichment sheets when the gas vertically passes through the enrichment body.

12. A method of introducing a solid sample to be tested using the sample introduction device for an ion mobility spectrometer of claim 3, comprising the steps of:

starting a heating part arranged outside the inner sleeve part, and continuously heating the inner cavity in the operation process to form a thermal resolution cavity;

rotating the outer end cap such that the outer end cap is disposed in the first position relative to the inner end cap;

introducing a solid sample to be tested into the thermal analysis cavity through the first outer opening on the outer end cover and the inner opening on the inner end cover, wherein the solid sample to be tested is heated in the thermal analysis cavity to form a gaseous sample to be tested;

and introducing a gaseous sample to be tested into the inlet of the migration tube through the inner-layer channel.

13. A method of introducing a gas sample to be tested using the sample introduction device for an ion mobility spectrometer of claim 8, comprising the steps of:

starting a heating part arranged outside the inner sleeve part, and continuously heating the inner cavity in the operation process to form a thermal resolution cavity;

rotating the outer end cap such that the outer end cap is disposed in the second position relative to the inner end cap;

introducing a gas sample to be detected into an inner layer channel through a second outer opening on the outer end cover and a sleeve cavity, and pre-concentrating on the enrichment body;

after the gas sample to be measured is pre-concentrated on the enrichment body for a preset time, rotating the outer end cover so that the outer end cover is arranged to be in the first position relative to the inner end cover;

introducing airflow onto the enrichment body through the thermal desorption cavity so as to analyze a sample to be detected pre-concentrated on the enrichment body and form a gaseous sample to be detected; and

and introducing a gaseous sample to be tested into the inlet of the migration tube through the inner-layer channel.

14. The method for introducing a gas sample to be tested into a sample introduction device of an ion mobility spectrometer as recited in claim 13, further comprising the steps of:

and starting a pulse heating device connected with the enrichment body to carry out controllable pulse heating on the enrichment body.

15. An ion mobility spectrometer, comprising: a migration tube for performing ionization and migration operations on a sample to be tested introduced therein, wherein the migration tube comprises: an ionization region in which sample molecules to be measured are ionized to form an ion cluster; and a migration zone where the ion clusters complete the directional migration and separation process; gas path means for supplying a carrier gas to the ionization region and a migration gas to the migration region; and a sample introduction device as in claim 1 for introducing a sample to be tested into an inlet of the migration tube.

16. The ion mobility spectrometer of claim 15, further comprising:

and the sample injection pump is used for providing negative pressure to introduce the gas sample to be detected into the sample injection device.