Multi-mode ion source combined equipment and detection method thereof

Abstract

The invention discloses a multi-mode ion source combination device and a detection method thereof.The multi-mode ion source combination device comprises a fixed shell, a heating module, two probe sample introduction modules, an ESI module, a voltage module and a control unit, the two probe sample introduction modules are located above and on the left side of the fixed shell respectively, the heating module is installed above the fixed shell, and the ESI module is installed on the left side of the fixed shell; the ESI module is installed on the left side of the fixed shell, the fixed shell is matched with a triple quadrupole mass spectrometer interface, and the control unit can control equipment to be switched in situ between a TD-ESI mode and a nano-ESI mode. The equipment does not need a solid-liquid conversion process, the detection speed is less than or equal to 1min, a 100-1000Da full molecular weight domain is covered, no sample transfer loss exists, complicated trace material evidences such as explosion residues, drug metabolites and biotoxins can be rapidly detected, the technical problems of difficulty in sampling, narrow range and low efficiency of an existing ion source are solved, and the equipment is suitable for on-site evidence collection and detection of public safety.

Description

Technical Field

[0001] This invention relates to the field of mass spectrometry analysis technology, and in particular to a multimodal ion source coupled device and its detection method. Background Technology

[0002] With the increasing demand for physical evidence analysis in the public security field, modern police evidence collection and testing faces two core challenges: sample complexity and testing diversity. Crime scene physical evidence (such as explosion residues, drug metabolites, biological fluid stains, trace dyes, etc.) includes both small molecule volatile components (such as drug additives and combustion accelerants) and large molecule non-volatile substances (such as protein toxins and synthetic cannabinoid polymers), requiring efficient detection across the entire molecular weight range.

[0003] The ion sources used in current mainstream detection equipment have significant technical defects: ESI ion source (atmospheric piezoelectric spray ion source): High ionization efficiency and wide range (100-1000Da), but requires a forced "solid-to-liquid" conversion process, slow detection speed (single sample pretreatment + detection takes 30 minutes), and dissolution and dilution lead to large detection losses, and trace samples are easily damaged.

[0004] Nano-ESI sources have the advantages of low flow rate, small droplet size and high ionization efficiency, with an ionization range of 100-1000 Da. However, the low flow rate leads to insufficient sensitivity. They also rely on the "solid-to-liquid" conversion, making it difficult to sample solids and trace surfaces.

[0005] Thermal desorption-electrospray ionization source (MSRIT / TD-ESI ionization source): simple sampling, no pretreatment required, and high ionization efficiency, but narrow ionization range (100-550 Da), unable to ionize thermally unstable compounds.

[0006] Therefore, it is necessary to design a multimodal ion source co-processing device and its detection method to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by proposing a multi-modal ion source combined device and its detection method. This device eliminates the need for a "solid-to-liquid" conversion process, has a detection speed of ≤1 minute, covers the full molecular weight range of 100-1000 Da, and has no sample transfer loss. It can rapidly detect complex trace evidence such as explosion residues, drug metabolites, and biotoxins, solving the technical pain points of existing ion sources, such as difficult sampling, narrow range, and low efficiency. It is suitable for on-site evidence collection and detection in public safety.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A multimodal ion source co-processing device includes a fixed housing, a heating module, two probe injection modules, an ESI module voltage module, and a control unit. The two probe injection modules are located above and to the left of the fixed housing, respectively. The heating module is installed above the fixed housing, and the ESI module is installed to the left of the fixed housing. The fixed housing is adapted to a triple quadrupole mass spectrometer interface. The control unit can control the device to switch in situ between TD-ESI mode and nano-ESI mode to achieve the detection of compounds in the molecular weight range of 100 Da to 1000 Da.

[0009] Preferably, the probe injection module includes a housing, a sampling probe, a heat dissipation layer, and a clamp. The clamp is installed inside the housing, the heat dissipation layer is fixedly connected to the outer wall of the housing, the sampling probe is fixedly connected to the fixed end of the clamp, and the side of the sampling probe away from the clamp extends to the outside. The sampling probe is made of carbon nanotube material, which has enrichment and conductivity properties, and can directly scrape or dip solid, liquid, and trace surface samples.

[0010] Preferably, the heating module includes a glass liner, a heating rod, a gas path, a heat insulation layer, and a first probe inlet. The heating rod has a maximum heating temperature of 320°C and a temperature fluctuation of ≤±1°C. The gas path adopts a nitrogen side-in, top-out design to deliver a hot nitrogen gas flow.

[0011] Preferably, the ESI module includes a glass tube, an air inlet, an ESI solution inlet, and a second probe inlet; the diameter of the front section of the glass tube is 50-100 micrometers; the air inlet is connected to a nitrogen source, and the ESI solution inlet can introduce a charged solvent; the ESI module can switch between TD-ESI and nano-ESI modes by fixing a preset position inside the housing.

[0012] Preferably, the voltage module provides temperature control voltage for the heating module and ionization high voltage for the ESI module, adapting to the different high voltage requirements of TD-ESI and nano-ESI.

[0013] Preferably, the control unit integrates temperature control, airflow control, high pressure control, flow rate control and position control functions, and can automatically adjust the operating parameters of each module and switch working modes.

[0014] The detection method of the multimodal ion source combined device described above includes the following steps: S1: Rapid sampling via probe injection module; S2: If detecting small molecule compounds <500Da, start the TD-ESI mode: the heating module thermally desorbs the sample, and the gaseous molecules are carried into the ESI region by the nitrogen flow and ionized by the charged solvent, and then introduced into the mass spectrometer for detection. S3: If detecting macromolecular compounds ≥500Da, start nano-ESI mode: the sampling probe is inserted into the glass tube and ionized under the action of a high voltage electric field and electrospray solution, and then introduced into the mass spectrometer for detection. S4: The two modes can be switched with one click by the control unit to realize in-situ continuous detection of mixed samples.

[0015] The present invention has the following beneficial effects: 1. Compared with existing technologies, carbon nanotube sampling probes enable rapid in-situ sampling of solid, trace surface, liquid, and gas samples, completely eliminating the "solid-to-liquid" conversion process, and improving the detection speed to within 1 minute, meeting the needs of rapid on-site evidence collection. 2. Compared with existing technologies, by switching between TD-ESI and nano-ESI in situ, the detection of compounds in the full range from 100Da to 1000Da can be achieved, covering both small molecule volatile components and large molecule non-volatile substances, and the one-time detection rate is significantly improved. 3. Compared with existing technologies, samples are directly detected in situ through probes, without transfer, dilution, or pretreatment steps, avoiding the loss of trace target substances and making detection loss close to zero; 4. Compared with existing technologies, the TD-ESI mode adopts precise temperature control (320℃±1℃) and a gentle thermal desorption design, which can detect thermally stable small molecules; the nano-ESI mode does not require heating, is suitable for thermally unstable large molecules, and covers a wide variety of complex evidence types. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a multimodal ion source co-processing device proposed in this invention; Figure 2 A schematic diagram of the added module; Figure 3 This is a schematic diagram of the probe injection module. Figure 4 This is a schematic diagram of the ESI module. Figure 5 Schematic diagram of the ion source for TD sample introduction; Figure 6 Schematic diagram of an ion source for ESI injection.

[0017] In the figure: 1 Fixed outer shell, 2 Heating module, 21 Glass liner, 22 Heating rod, 23 Gas path, 24 Heat insulation layer, 25 First probe injection port, 3 Probe injection module, 31 Heat dissipation layer, 32 Clamp, 33 Sampling probe, 4 ESI module, 41 Second probe injection port, 42 ESI solution inlet, 43 Glass tube, 44 Gas inlet. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0019] Reference Figures 1-6 A multimodal ion source co-processing device includes a fixed housing 1, a heating module 2, two probe injection modules 3, an ESI module 4, a voltage module, and a control unit. The two probe injection modules 3 are located above and to the left of the fixed housing 1, respectively. The heating module 2 is installed above the fixed housing 1, and the ESI module 4 is installed to the left of the fixed housing 1. The fixed housing 1 is adapted to a triple quadrupole mass spectrometer interface. The control unit can control the device to switch in situ between TD-ESI mode and nano-ESI mode to realize the detection of compounds in the molecular weight range of 100 Da to 1000 Da.

[0020] The probe injection module 3 enables rapid in-situ sampling of solid, liquid, and gas samples. After sampling, the sample is directly inserted into the ion source for detection without sample transfer loss. The probe injection module 3 includes a shell, a sampling probe 33, a heat dissipation layer 31, and a clamp 32. The clamp 32 is installed inside the shell, the heat dissipation layer 31 is fixedly connected to the outer wall of the shell, and the sampling probe 33 is fixedly connected to the fixed end of the clamp 32. The side of the sampling probe 33 away from the clamp 32 extends to the outside. The sampling probe 33 is made of carbon nanotube material, which has enrichment and conductivity properties. It can directly scrape or dip solid, liquid, and trace surface samples without the need for "solid-to-liquid" conversion. The clamp 32 enables rapid fixing and disassembly of the sampling probe 33, and the heat dissipation layer 31 prevents the sample from denaturing due to excessive probe temperature.

[0021] The heating module 2 is adapted to the TD-ESI working mode and performs thermal desorption on small molecule volatile compounds (<500 Da) on the sampling probe 33, converting them into gaseous neutral molecules. The heating module 2 includes a glass liner 21, a heating rod 22, a gas path 23, a heat insulation layer 24, and a first probe inlet 25. The heating rod 22 has a maximum heating temperature of 320℃ and a temperature fluctuation of ≤±1℃. The gas path 23 adopts a nitrogen side-in, top-out design to deliver hot nitrogen gas flow and ensure that the hot nitrogen gas flow uniformly envelops the sample.

[0022] The ESI module 4 includes a glass tube 43, an air inlet 44, an ESI solution inlet 42, and a second probe inlet 41. The front diameter of the glass tube 43 is 50-100 micrometers, which is suitable for nano-spray ionization. The air inlet 44 is connected to a nitrogen source, and the ESI solution inlet 42 can introduce charged solvents. The ESI module 4 can switch between TD-ESI and nano-ESI modes by fixing a preset position inside the outer shell 1.

[0023] The voltage module provides temperature control voltage for heating module 2 and ionization high voltage for ESI module 4, adapting to the different high voltage requirements of TD-ESI and nano-ESI. The control unit integrates temperature control, airflow control, high voltage control, flow control and position control functions, and can automatically adjust the operating parameters of each module and switch working modes.

[0024] The detection method of the multimodal ion source combined device described above includes the following steps: S1: Rapid sampling via probe injection module 3; S2: If detecting small molecule compounds <500Da, start the TD-ESI mode: heating module 2 thermally desorbs the sample, and gaseous molecules are carried into the ESI region by nitrogen flow and ionized by charged solvent, and then introduced into the mass spectrometer for detection. S3: If detecting macromolecular compounds ≥500Da, start nano-ESI mode: the sampling probe 33 is inserted into the glass tube 43, ionized under the action of high voltage electric field and electrospray solution, and introduced into the mass spectrometer for detection; S4: The two modes can be switched with one click by the control unit to realize in-situ continuous detection of mixed samples.

[0025] The functional principle of this invention can be explained through the following operational methods: 1. Detection of small molecule explosion residues (TD-ESI mode) Equipment preparation: Install the multimodal ion source coupling device onto the MS inlet of the triple quadrupole mass spectrometer through the fixed housing 1, connect the nitrogen source, ESI solution storage tank, voltage module and control unit, and set the TD-ESI mode operating parameters: heating temperature 280℃, nitrogen flow rate 0.5L / min, ionization voltage 3.5kV, ESI solution (0.1% formic acid aqueous solution) flow rate 5μL / min; Sampling: A carbon nanotube sampling probe was used to scrape trace amounts of residue from the ground at the explosion site; Sample introduction: The sampling probe 33 is fixed by the clamp 32 and inserted into the first probe injection port 25 of the heating module 2, ensuring that the probe tip is located at the center of the glass liner tube 21; Thermal desorption and ionization: Heating module 2 is activated, and the temperature rises to 280°C and stabilizes within 30 seconds. The small molecule combustion aids (molecular weight 150-400 Da) in the residue are thermally desorbed into gaseous molecules, which enter the ESI region under the influence of nitrogen flow and combine with the positively charged formic acid solution to form ions. Detection: Ions are introduced into the mass spectrometer through the MS inlet to complete qualitative and quantitative analysis. The entire detection process takes 45 seconds with no sample loss.

[0026] 2. Detection of macromolecular synthetic cannabinoid polymers (nano-ESI mode) Equipment preparation: Switch to nano-ESI mode via the control unit and set the parameters as follows: ionization voltage 4.5kV, nitrogen flow rate 0.3L / min, ESI solution (0.1% ammonium acetate aqueous solution) flow rate 1μL / min, and turn off heating module 2; Sampling: Use carbon nanotube sampling probe 33 to pick up solid samples suspected of containing synthetic cannabinoid polymers; Sample introduction: Insert the probe into the glass tube 43 of ESI module 4, ensuring that the distance between the probe tip and the front outlet of the glass tube 43 is 2mm; Ionization: The voltage module applies high voltage, and the ESI solution is continuously introduced from the inlet. The synthetic cannabinoid polymer (molecular weight 600-900 Da) on the probe is ionized under the action of high voltage electric field and electrospray. The nitrogen gas flow blows away the excess solvent. Detection: Charged ion mass spectrometry enables rapid detection of macromolecular polymers, with a detection time of 50 seconds and a detection sensitivity that is 30% higher than that of traditional nano-ESI.

[0027] 3. In-situ switching detection of mixed samples Sample: A mixed trace sample containing both small molecule drug additives (molecular weight 300 Da) and large molecule protein toxins (molecular weight 800 Da); Testing process: First, the TD-ESI mode is activated, and the small molecule additives are detected according to the small molecule explosion residue detection parameters, which takes 40 seconds. With a single click from the control unit, the device can switch to nano-ESI mode. Without changing the probe, it can directly detect macromolecular toxins using the parameters for detecting macromolecular synthetic cannabinoid polymers, taking 55 seconds. Results: Two molecular weight domain compounds were detected in a single sampling, with no additional sample consumption and a detection rate of over 95%.

[0028] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A multimodal ion source co-processing device, characterized in that, include: The device consists of a fixed housing (1), a heating module (2), two probe injection modules (3), an ESI module (4), a voltage module, and a control unit. The two probe injection modules (3) are located above and to the left of the fixed housing (1), respectively. The heating module (2) is installed above the fixed housing (1), and the ESI module (4) is installed to the left of the fixed housing (1). The fixed housing (1) is compatible with a triple quadrupole mass spectrometer interface. The control unit can control the device to switch in situ between TD-ESI mode and nano-ESI mode to achieve the detection of compounds in the molecular weight range of 100Da to 1000Da.

2. The multimodal ion source co-processing device according to claim 1, characterized in that: The probe injection module (3) includes a shell, a sampling probe (33), a heat dissipation layer (31), and a clamp (32). The clamp (32) is installed inside the shell, the heat dissipation layer (31) is fixedly connected to the outer wall of the shell, the sampling probe (33) is fixedly connected to the fixed end of the clamp (32), and the sampling probe (33) extends to the outside on the side away from the clamp (32). The sampling probe (33) is made of carbon nanotube material, which has enrichment and conductivity properties, and can directly scrape or dip solid, liquid, and trace surface samples.

3. The multimodal ion source co-processing device according to claim 2, characterized in that: The heating module (2) includes a glass liner (21), a heating rod (22), a gas path (23), a heat insulation layer (24), and a first probe injection port (25). The heating rod (22) has a maximum heating temperature of 320℃ and a temperature fluctuation of ≤±1℃. The gas path (23) adopts a nitrogen side-in and top-out design to transport hot nitrogen gas flow.

4. The multimodal ion source co-processing device according to claim 3, characterized in that: The ESI module (4) includes a glass tube (43), an air inlet (44), an ESI solution inlet (42), and a second probe inlet (41); the front end diameter of the glass tube (43) is 50-100 micrometers; the air inlet (44) is connected to a nitrogen source, and the ESI solution inlet (42) can introduce a charged solvent; the ESI module (4) can switch between TD-ESI and nano-ESI modes by fixing a preset position inside the outer shell (1).

5. The multimodal ion source co-processing device according to claim 4, characterized in that: The voltage module provides temperature control voltage for the heating module (2) and ionization high voltage for the ESI module (4), adapting to the different high voltage requirements of TD-ESI and nano-ESI.

6. The multimodal ion source co-processing device according to claim 5, characterized in that: The control unit integrates temperature control, airflow control, high pressure control, flow rate control and position control functions, and can automatically adjust the operating parameters of each module and switch working modes.

7. The detection method of a multimodal ion source coupled device according to any one of claims 4-6, characterized in that, Includes the following steps: S1: Rapid sampling via probe injection module (3); S2: If detecting small molecule compounds <500Da, start the TD-ESI mode: heating module (2) thermally desorbs the sample, gaseous molecules are carried into the ESI region by nitrogen flow and ionized by charged solvent, and introduced into the mass spectrometer for detection; S3: If detecting macromolecular compounds ≥500Da, start nano-ESI mode: the sampling probe (33) is inserted into the glass tube (43), ionized under the action of high voltage electric field and electrospray solution, and introduced into the mass spectrometer for detection; S4: The two modes can be switched with one click by the control unit to realize in-situ continuous detection of mixed samples.

Images