Novel Ion Source Structured Soil Phthalate Mass Spectrometry Detection Device and Method

Abstract

This invention belongs to the field of soil phthalic acid technology, specifically a novel ion source structure soil phthalic acid mass spectrometry detection device and method, including a base support, on the outer surface of which a detection device and a holding device are disposed. This novel ion source structure soil phthalic acid mass spectrometry detection device and method, by setting up the detection device, can rapidly detect phthalic acid in soil, omitting most sample pretreatment steps. The detection time for a single sample can be shortened to seconds to minutes, supporting on-site / quasi-in-situ screening. Pulse desorption focusing of micro-area samples and a multi-channel synchronous ionization design (main ionization + gas curtain focusing / purification) greatly improve ionization efficiency and reduce matrix inhibition. Combined with the high sensitivity of mass spectrometry, sub-ppb or even ppt detection limits can be achieved. Strong resistance to matrix interference is demonstrated. The auxiliary purification gas curtain is a key innovation, effectively physically isolating most soil particles, salts, macromolecular humic acids, and other interfering substances.

Description

Technical Field

[0001] This invention relates to the field of soil phthalic acid technology, and in particular to a novel ion source structure soil phthalic acid mass spectrometry detection device and method. Background Technology

[0002] Soil phthalates refer to phthalic acid esters that exist in the soil environment. They mainly originate from plastic products, especially as plasticizers, agricultural films, sewage sludge, and atmospheric deposition. Due to their environmental persistence, bioaccumulation potential, and endocrine-disrupting toxicity, they are considered important soil organic pollutants, posing potential risks to ecosystem health and agricultural product safety. Existing methods for detecting phthalates in soil are difficult due to the complexity of the matrix and soil composition (organic matter, minerals, moisture, etc.), which severely interfere with the extraction and ionization of target analytes (PAEs). Pretreatment is cumbersome: traditional methods (such as GC-MS and LC-MS) require complex steps including sample collection, transportation, drying, grinding, extraction (Soxhlet extraction, ultrasonication, accelerated solvent extraction, etc.), purification, and concentration, which are time-consuming (from several hours to several days), costly, and prone to introducing errors and losses. High sensitivity is required: PAEs are trace pollutants in the environment with low regulatory limits, necessitating highly sensitive detection methods. Traditional ion sources have limitations: commonly used electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) sources typically require liquid injection or complex vaporization / derivation steps, making direct analysis of solid soil samples difficult. Laser desorption / ionization sources (such as MALDI) require matrix assistance and are sensitive to soil heterogeneity. Summary of the Invention

[0003] To address the existing technical problems of cumbersome pretreatment, high sensitivity requirements, and limitations of traditional ion sources for soil phthalic acid detection, this invention proposes a novel ion source structure for soil phthalic acid mass spectrometry detection device and method.

[0004] The present invention proposes a novel ion source structure soil phthalic acid mass spectrometry detection device, which includes a base support, and the outer surface of the base support is provided with a detection device and a holding device.

[0005] The detection device is located on the outer surface of the base support and detects soil powder. The detection device includes a focused pulsed infrared laser, which is used to emit laser light into the soil.

[0006] The holding device is located on the upper surface of the base of the base support and holds the soil to be tested. The holding device includes a sample stage, which can be moved, deflected, and tilted to dispose of the soil after testing.

[0007] Preferably, the detection device further includes a mass spectrometer, which is fixedly mounted on the upper surface of the base support. A conveying connector is fixedly mounted on the upper surface of the base support, and the conveying connector is fixedly mounted on one end of the detection interface of the mass spectrometer.

[0008] Preferably, the outer surface of the base bracket is rotatably connected to the outer surface of the focused pulsed infrared laser via a bearing, and a deflection motor is fixedly installed on the outer surface of the base bracket. One end of the output shaft of the deflection motor drives the focused pulsed infrared laser to deflect via a gear set.

[0009] Preferably, a main ionization channel is fixedly installed on the outer surface of the base support, an ion nozzle is fixedly connected to the lower surface of the main ionization channel, a reagent container is fixedly installed on the outer surface of the base support, a detection suction pump is fixedly connected to the outer surface of the reagent container, and the output end of the detection suction pump is fixedly connected to the outer surface of the main ionization channel through a connecting pipe.

[0010] Preferably, a purification channel is fixedly installed on the outer surface of the base bracket, a purification nozzle is fixedly connected to the outer surface of the purification channel, a purification tank containing high-purity nitrogen is fixedly installed on the outer surface of the base bracket, a purification suction pump is fixedly connected to the outer surface of the purification tank, and the output end of the purification suction pump is fixedly connected to the outer surface of the purification channel through a connecting pipe.

[0011] Preferably, the holding device further includes a limiting slide groove, a movable block is slidably inserted into the inner wall of the limiting slide groove, a movable rack is fixedly installed on the lower surface of the movable block, a rotating shaft with gears is rotatably connected to the outer surface of the base bracket through a bearing seat, the gears of the rotating shaft mesh with the movable rack, a drive motor is fixedly installed on the outer surface of the base bracket, one end of the output shaft of the drive motor drives the rotating shaft to rotate through a gear, the two rotating shafts are connected by a synchronous belt and a synchronous pulley, a rotating seat is rotatably connected to the upper surface of the movable block through a bearing seat, and the outer surface of the rotating seat is fixedly installed to the lower surface of the sample stage.

[0012] Preferably, a flipping gear is fixedly installed at both ends of the rotating seat, and a flipping rack is fixedly installed on the upper surface of the limiting slide groove, wherein the flipping gear meshes with the flipping rack.

[0013] Preferably, a limiting plate is fixedly installed on the upper surface of the limiting groove, and a limiting frame with balls is fixedly installed on the outer surface of the rotating seat, wherein the balls of the limiting frame roll in contact with the outer surface of the limiting plate.

[0014] Preferably, a collection groove is fixedly installed on the outer surface of the base bracket, an electric push rod is fixedly installed on the upper surface of the collection groove, a rotary motor is fixedly installed on the outer surface of the electric push rod, and a cleaning scraper is fixedly installed at one end of the output shaft of the rotary motor.

[0015] The present invention proposes a method for detecting phthalic acid in soil using a novel ion source structure mass spectrometry device, comprising the following steps: S1: Place a small amount of soil sample (1-10 mg) on ​​the sample stage. Start the deflection motor to drive the focused pulsed infrared laser to deflect. Adjust the irradiation position and trigger the focused pulsed infrared laser to instantly desorb PAEs and a small amount of matrix molecules in the selected micro-area, forming an upward-moving micro-plume. S2: Simultaneously, the main ionization channel is activated, and the detection pump draws methanol-water solution containing dopant ammonium formate from the reagent tank. High pressure is applied, and after entering the main ionization channel, it passes through the ion nozzle to generate a stable spray that is sprayed inward and downward. The plume generates reagent ions that cover the desorption plume path.

[0016] S3: The auxiliary purification air curtain is activated. The purification suction pump draws the gas from the purification tank into the purification channel and sprays it out through the purification nozzle, forming a ring-shaped protective focusing airflow. During the upward movement of the desorbed PAE molecules, most of the matrix particles and debris are purified and removed by the outer auxiliary air curtain.

[0017] S4: The microfluid from soil desorption is focused to the central region, where it collides with the reagent ionosphere generated by the main ionization channel and is ionized. The reaction gases doped in the outer gas curtain may participate in the ionization process. The generated PAE characteristic ions are efficiently drawn into the ion nozzle and enter the detection interface of the mass spectrometer; the mass spectrometer then performs the detection.

[0018] S5: After the test is completed, the drive motor starts and drives the rotating shaft to rotate. The gear on the rotating shaft drives the moving rack to move. The moving rack drives the rotating seat to move through the moving block. The limit frame ball on the rotating seat moves on the limit plate. When the flipping gear on the rotating seat meshes with the flipping rack, it drives the rotating seat to flip, thereby driving the sample stage to flip and pour the surface soil into the collection tank. After the cleaning scraper comes into contact with the sample stage by the push of the electric push rod, the rotating motor drives the cleaning scraper to rotate and clean the surface of the sample stage.

[0019] The beneficial effects of this invention are as follows: 1. By setting up a detection device, it is possible to quickly detect phthalates in soil, eliminating most sample pretreatment steps. The detection time for a single sample can be shortened to seconds to minutes. It supports on-site / quasi-in-situ screening, pulse desorption focusing on micro-area samples, and a multi-channel synchronous ionization design (main ionization + gas curtain focusing / purification) that greatly improves ionization efficiency and reduces matrix inhibition. Combined with the high sensitivity of mass spectrometry, it can achieve sub-ppb or even ppt detection limits. It has strong resistance to matrix interference. The auxiliary purification gas curtain is a key innovation, effectively physically isolating most soil particles, salts, macromolecular humic acid and other interfering substances, significantly reducing background noise and ion source contamination, and improving the accuracy and reproducibility of trace PAEs detection in complex soil matrices. The pulse energy is focused on a small area, causing little damage to the sample, and can achieve spatial resolution analysis of PAEs distribution on soil profiles and particle surfaces. It solves the technical problems of cumbersome pretreatment, high sensitivity requirements and limitations of traditional ion sources for existing phthalate detection in soil. 2. By setting up a holding device, the sample stage holding the sample can be cleaned. In order to drive the sample stage to rotate, the rotation gear and the rotation rack are combined to drive the rotation gear to rotate, which in turn drives the sample stage to rotate. In order to clean the sample stage, the push rod is driven to push the cleaning scraper to contact the sample stage, and the rotation of the cleaning scraper cleans the sample stage. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a novel ion source structure soil phthalic acid mass spectrometry detection device proposed in this invention; Figure 2 This is a perspective view of the delivery connector structure of a novel ion source structure soil phthalic acid mass spectrometry detection device proposed in this invention; Figure 3 This is a three-dimensional view of the purification channel structure of a novel ion source structure soil phthalic acid mass spectrometry detection device proposed in this invention; Figure 4 This is a three-dimensional view of the main ionization channel structure of a novel ion source structure soil phthalic acid mass spectrometry detection device proposed in this invention; Figure 5 This is a perspective view of the sample stage structure of a novel ion source structure soil phthalic acid mass spectrometry detection device proposed in this invention; Figure 6 This is a perspective view of the rotating shaft structure of a novel ion source structure soil phthalic acid mass spectrometry detection device proposed in this invention; Figure 7 This is a three-dimensional view of the moving block structure of a novel ion source structure soil phthalic acid mass spectrometry detection device proposed in this invention; Figure 8This is a perspective view of the rotating rack structure of a novel ion source structure for soil phthalic acid mass spectrometry detection device proposed in this invention. In the figure: 1. Base support; 2. Mass spectrometer; 21. Conveyor connector; 22. Focused pulsed infrared laser; 23. Deflection motor; 3. Main ionization channel; 31. Ion nozzle; 32. Reagent container; 33. Detection suction pump; 34. Purification channel; 35. Purification nozzle; 36. Purification container; 37. Purification suction pump; 4. Limiting slide; 41. Moving block; 42. Moving rack; 43. Rotating shaft; 44. Drive motor; 45. Rotating seat; 46. Sample stage; 47. Rotating gear; 48. Rotating rack; 5. Limiting plate; 51. Limiting frame; 52. Collection tank; 53. Electric push rod; 54. Rotating motor; 55. Cleaning scraper. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] Reference Figures 1-8 A novel ion source structure soil phthalic acid mass spectrometry detection device includes a base support 1, on the outer surface of which a detection device and a holding device are provided.

[0023] like Figures 2-4 As shown, in order to quickly detect phthalates in soil, the detection device is located on the outer surface of the base support 1 and detects soil powder. The detection device includes a focused pulsed infrared laser 22, which is used to emit laser light into the soil.

[0024] Specifically, in order to detect phthalates in soil, the detection device also includes a mass spectrometer 2, which is fixedly installed on the upper surface of the base support 1. A conveyor connector 21 is fixedly installed on the upper surface of the base support 1, and the conveyor connector 21 is fixedly installed at one end of the detection interface of the mass spectrometer 2. The mass spectrometer 2 can detect soil and can select full scan, selected ion monitoring SIM, tandem mass spectrometry MS / MS and other modes. The conveyor connector 21 is conical to facilitate the entry of gas flow.

[0025] Specifically, the outer surface of the base bracket 1 is rotatably connected to the outer surface of the focused pulsed infrared laser 22 via bearings. A deflection motor 23 is fixedly installed on the outer surface of the base bracket 1. One end of the output shaft of the deflection motor 23 drives the focused pulsed infrared laser 22 to deflect via a gear set. The focused pulsed infrared laser 22 has a wavelength selected in the band where soil matrix such as silicate and water absorption is weak, but PAE molecules or their functional groups such as C=O have characteristic absorption, for example, ~3 μm or ~10.6 μm CO2 laser. The pulse width is in the nanosecond to microsecond range. The laser is focused on a small area of ​​the sample, tens to hundreds of micrometers, and instantly generates local high temperature, so that the PAEs and a small amount of matrix in the area can be effectively volatilized / desorbed to form a micro plume. At the same time, it avoids complex side reactions and instrument contamination caused by overheating of a large area of ​​soil.

[0026] Specifically, a main ionization channel 3 is fixedly installed on the outer surface of the base support 1, and an ion nozzle 31 is fixedly connected to the lower surface of the main ionization channel 3. A reagent container 32 is fixedly installed on the outer surface of the base support 1, and a detection suction pump 33 is fixedly connected to the outer surface of the reagent container 32. The output end of the detection suction pump 33 is fixedly connected to the outer surface of the main ionization channel 3 through a connecting pipe. Reagent ions or plasma for ionizing and desorbing gaseous molecules are generated. Multiple ion nozzles 31 are arranged in a ring. A methanol / water solution containing dopants such as ammonium formate or ammonium acetate is introduced. High pressure is applied to generate a stable electrospray plume. The flow rate is 5 μL / min total, and the spray voltage is +3.5kV.

[0027] Specifically, to prevent impurities from rising, a purification channel 34 is fixedly installed on the outer surface of the base support 1. A purification nozzle 35 is fixedly connected to the outer surface of the purification channel 34. A purification tank 36 containing high-purity nitrogen is fixedly installed on the outer surface of the base support 1. A purification suction pump 37 is fixedly connected to the outer surface of the purification tank 36. The output end of the purification suction pump 37 is fixedly connected to the outer surface of the purification channel 34 through a connecting pipe. The purification channel 34 generates an annular, converging airflow curtain of pure gas such as high-purity nitrogen, zero-grade air, or a small amount of reaction / cleaning gas such as ammonia or ozone. The high-purity nitrogen has a flow rate of 1-3 L / min and can be doped with 0.1% ammonia. This prevents a large number of non-target matrix components such as particulate matter, salt crystals, and large molecular organic fragments carried in the soil desorption plume from directly impacting the main ionization zone and the mass spectrometer inlet, significantly reducing pollution and background noise. Focusing guidance: It helps to focus the desorbed target molecule PAEs vapor to the central main ionization region. The purification channel 34 opens at 0.8-1.5 ms.

[0028] like Figures 5-8As shown, in order to hold the soil, the holding device is located on the upper surface of the base of the base support 1 and holds the soil to be tested. The holding device includes a sample stage 46, which can tilt and pour the soil after testing by moving and deflecting.

[0029] Specifically, the holding device also includes a limiting slide 4, a movable block 41 is slidably inserted into the inner wall of the limiting slide 4, a movable rack 42 is fixedly installed on the lower surface of the movable block 41, a rotating shaft 43 with gears is rotatably connected to the outer surface of the base support 1 through a bearing seat, the gear of the rotating shaft 43 meshes with the movable rack 42, a drive motor 44 is fixedly installed on the outer surface of the base of the base support 1, one end of the output shaft of the drive motor 44 drives the rotating shaft 43 to rotate through the gear, the two rotating shafts 43 are connected by a synchronous belt and a synchronous pulley for transmission, a rotating seat 45 is rotatably connected to the upper surface of the movable block 41 through a bearing seat, and the outer surface of the rotating seat 45 is fixedly installed with the lower surface of the sample stage 46.

[0030] To facilitate cleaning of the sample stage 46, the rotation of the shaft 43 is achieved by starting the drive motor 44, which in turn moves the moving block 41, allowing the sample stage 46 to move away from the base support 1. The sample stage 46 has a heating module, with an optional mild heating module (<100°C) to assist in the desorption of low-volatility PAEs and prevent thermal decomposition. The sample stage 46 is made of corrosion-resistant and easy-to-clean materials such as stainless steel or polytetrafluoroethylene coated metal.

[0031] Specifically, in order to drive the sample stage 46 to deflect, the two ends of the rotating seat 45 are fixedly installed with a rotating gear 47, and the upper surface of the limiting slide groove 4 is fixedly installed with a rotating rack 48, and the rotating gear 47 meshes with the rotating rack 48.

[0032] Specifically, in order to limit the sample stage 46, a limiting plate 5 is fixedly installed on the upper surface of the limiting slide 4, and a limiting frame 51 with ball bearings is fixedly installed on the outer surface of the rotating seat 45. The ball bearings of the limiting frame 51 roll and engage with the outer surface of the limiting plate 5.

[0033] Specifically, in order to clean the sample stage 46, a collection tank 52 is fixedly installed on the outer surface of the base bracket 1, an electric push rod 53 is fixedly installed on the upper surface of the collection tank 52, a rotary motor 54 is fixedly installed on the outer surface of the electric push rod 53, and a cleaning scraper 55 is fixedly installed at one end of the output shaft of the rotary motor 54.

[0034] In order to clean the sample stage 46, the cleaning scraper 55 can be brought into contact with the sample stage 46 by driving the electric push rod 53. A cleaning nozzle can be set on the base bracket 1 to deliver cleaning fluid to rinse the sample stage 46 and the cleaning scraper 55.

[0035] The present invention proposes a method for detecting phthalic acid in soil using a novel ion source structure mass spectrometry device, comprising the following steps: S1: Place a small amount of 1-10 mg soil sample on the sample stage 46. The soil sample can be raw, air-dried or simply pressed. Start the deflection motor 23 to drive the focused pulsed infrared laser 22 to deflect. Adjust the irradiation position and trigger the focused pulsed infrared laser 22 to instantly desorb PAEs and a small amount of matrix molecules in the selected micro-area, forming an upward-moving micro-plume. S2: Simultaneously, the main ionization channel 3 is activated, and the detection suction pump 33 draws methanol aqueous solution containing dopant ammonium formate from the reagent tank 32. High pressure is applied, and after entering the main ionization channel 3, it passes through the ion nozzle 31 to generate a stable spray, which is sprayed inward and downward. The plume generates reagent ions to cover the desorption plume path. S3: The auxiliary purification air curtain is activated. The purification suction pump 37 draws the gas in the purification tank 36 into the purification channel 34 and sprays it out through the purification nozzle 35 to form a ring-shaped protective focusing airflow. During the upward movement of the desorbed PAEs molecules, most of the matrix particles and fragments are purified and removed by the outer auxiliary air curtain. S4: The microfluid from soil desorption is focused to the central region and ionized by colliding with the reagent ionization generated by the main ionization channel 3. The reaction gas doped in the outer gas curtain may participate in the ionization process. The generated PAE characteristic ions are efficiently drawn into the ion nozzle 31 and enter the detection interface of the mass spectrometer 2; the mass spectrometer 2 performs detection. S5: After the test is completed, the drive motor 44 starts and drives the rotating shaft 43 to rotate. The gear on the rotating shaft 43 drives the moving rack 42 to move. The moving rack 42 drives the rotating seat 45 to move through the moving block 41. The ball bearings of the limiting frame 51 on the rotating seat 45 move on the limiting plate 5. When the flipping gear 47 on the rotating seat 45 meshes with the flipping rack 48, it drives the rotating seat 45 to flip, thereby driving the sample stage 46 to flip and pour the surface soil into the collection tank 52. After the cleaning scraper 55 contacts the sample stage 46 by the push of the electric push rod 53, the rotating motor 54 drives the cleaning scraper 55 to rotate and clean the surface of the sample stage 46. The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the protection scope of the present invention.

Claims

1. A novel ion source structure soil o-benzene mass spectrometry detection device, comprising a base support (1), characterized in that: The outer surface of the base support (1) is provided with a detection device and a holding device; The detection device is located on the outer surface of the base support (1) and detects soil powder. The detection device includes a focused pulsed infrared laser (22), which is used to emit laser light into the soil. The detection device also includes a mass spectrometer (2), which is fixedly installed on the upper surface of the base support (1). A conveying connector (21) is fixedly installed on the upper surface of the base support (1), and the conveying connector (21) is fixedly installed at one end of the detection interface of the mass spectrometer (2). The outer surface of the base bracket (1) is rotatably connected to the outer surface of the focused pulsed infrared laser (22) through a bearing. A deflection motor (23) is fixedly installed on the outer surface of the base bracket (1). One end of the output shaft of the deflection motor (23) drives the focused pulsed infrared laser (22) to deflect through a gear set. The outer surface of the base support (1) is fixedly installed with a main ionization channel (3), the lower surface of the main ionization channel (3) is fixedly connected with an ion nozzle (31), the outer surface of the base support (1) is fixedly installed with a reagent container (32), the outer surface of the reagent container (32) is fixedly connected with a detection suction pump (33), and the output end of the detection suction pump (33) is fixedly connected to the outer surface of the main ionization channel (3) through a connecting pipe. A purification channel (34) is fixedly installed on the outer surface of the base bracket (1). A purification nozzle (35) is fixedly connected to the outer surface of the purification channel (34). A purification tank (36) with high-purity nitrogen is fixedly installed on the outer surface of the base bracket (1). A purification suction pump (37) is fixedly connected to the outer surface of the purification tank (36). The output end of the purification suction pump (37) is fixedly connected to the outer surface of the purification channel (34) through a connecting pipe. The holding device is located on the upper surface of the base of the base support (1) and holds the soil to be tested. The holding device includes a sample stage (46), which can tilt and pour the soil after testing by moving and deflecting.

2. The novel ion source structure soil phthalate mass spectrometry detection device according to claim 1, characterized in that: The holding device also includes a limiting slide groove (4), a moving block (41) is slidably inserted into the inner wall of the limiting slide groove (4), a moving rack (42) is fixedly installed on the lower surface of the moving block (41), a rotating shaft (43) with gears is rotatably connected to the outer surface of the base support (1) through a bearing seat, the gear of the rotating shaft (43) meshes with the moving rack (42), a drive motor (44) is fixedly installed on the outer surface of the base of the base support (1), one end of the output shaft of the drive motor (44) drives the rotating shaft (43) to rotate through the gear, the two rotating shafts (43) are connected by a synchronous belt and a synchronous pulley, a rotating seat (45) is rotatably connected to the upper surface of the moving block (41) through a bearing seat, and the outer surface of the rotating seat (45) is fixedly installed with the lower surface of the sample stage (46).

3. The novel ion source structure soil o-benzene mass spectrometry detection device according to claim 2, characterized in that: The rotating seat (45) is fixedly mounted with a flip gear (47) at both ends, and a flip rack (48) is fixedly mounted on the upper surface of the limiting slide groove (4). The flip gear (47) meshes with the flip rack (48).

4. The novel ion source structure soil o-benzene mass spectrometry detection device according to claim 3, characterized in that: A limiting plate (5) is fixedly installed on the upper surface of the limiting groove (4), and a limiting frame (51) with balls is fixedly installed on the outer surface of the rotating seat (45). The balls of the limiting frame (51) roll and cooperate with the outer surface of the limiting plate (5).

5. The novel ion source structure soil phthalic acid mass spectrometry detection device according to claim 4, characterized in that: A collection trough (52) is fixedly installed on the outer surface of the base bracket (1). An electric push rod (53) is fixedly installed on the upper surface of the collection trough (52). A rotary motor (54) is fixedly installed on the outer surface of the electric push rod (53). A cleaning scraper (55) is fixedly installed at one end of the output shaft of the rotary motor (54).

6. A detection method for a novel ion source structure soil phthalic acid mass spectrometry detection device, using the novel ion source structure soil phthalic acid mass spectrometry detection device as described in claim 5, characterized in that: S1: Place a small amount of 1-10 mg soil sample on the sample stage (46), start the deflection motor (23) to drive the focused pulsed infrared laser (22) to deflect, adjust the irradiation position, trigger the focused pulsed infrared laser (22), and instantly desorb PAEs and a small amount of matrix molecules in the selected micro area to form an upward-moving micro plume; S2: At the same time, the main ionization channel (3) is started, and the detection pump (33) draws methanol aqueous solution containing dopant ammonium formate in the reagent tank (32), applies high pressure, and enters the main ionization channel (3) and passes through the ion nozzle (31) to generate a stable spray, which is sprayed inward and downward. The plume generates reagent ion body covering the desorption plume path. S3: The auxiliary purification air curtain is activated. The purification suction pump (37) draws the gas in the purification tank (36) into the purification channel (34) and sprays it out through the purification nozzle (35) to form a ring-shaped protective focusing airflow. During the upward movement of the desorbed PAEs molecules, most of the matrix particles and fragments are purified and removed by the outer auxiliary air curtain. S4: The microfluid from soil desorption is focused to the central region and ionized by colliding with the reagent ionization generated by the main ionization channel (3). The reaction gas doped in the outer gas curtain may participate in the ionization process. The generated PAE characteristic ions are efficiently drawn into the ion nozzle (31) and enter the detection interface of the mass spectrometer (2); the mass spectrometer (2) performs detection; S5: After the detection is completed, the drive motor (44) is started and drives the rotating shaft (43) to rotate. The gear on the rotating shaft (43) drives the moving rack (42) to move. The moving rack (42) moves through the moving block (41). The rotating seat (45) is moved, and the ball bearings of the limiting frame (51) on the rotating seat (45) move on the limiting plate (5). When the flipping gear (47) on the rotating seat (45) meshes with the flipping rack (48), the rotating seat (45) is flipped, thereby causing the sample stage (46) to flip and pour the surface soil into the collection tank (52). After the cleaning scraper (55) comes into contact with the sample stage (46) by the push of the electric push rod (53), the rotary motor (54) drives the cleaning scraper (55) to rotate and clean the surface of the sample stage (46).

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