Liquid chromatography-mass spectrometry device based on microwave plasma torch ion source

Abstract

The utility model discloses a liquid chromatography-mass spectrometry device based on a microwave plasma torch ion source. The liquid chromatography-mass spectrometry device comprises a base; the microwave plasma generator base and the atomizer base are arranged on the base; the microwave plasma generator is mounted on the microwave plasma generator base; the atomizer is mounted on the atomizer base; the high performance liquid chromatograph is connected with the atomizer; and the intersection point of the mass spectrometer, the spray outlet of the atomizer and the microwave plasma torch outlet of the microwave plasma generator is opposite to the mass spectrum inlet of the mass spectrometer. The device disclosed by the utility model can ionize the low-polarity compound through the microwave plasma torch ion source without carrying out pretreatment modes such as derivatization on a sample in advance, so that the problem that a conventional liquid chromatograph-mass spectrometer cannot analyze the low-polarity compound which is difficult to ionize is solved. The device is convenient to disassemble and assemble, can be exchanged with other ion sources, and widens the detection range of the liquid chromatograph-mass spectrometer.

Description

Technical Field

[0001] The utility model relates to the field of liquid chromatography - mass spectrometry devices, and particularly relates to a liquid chromatography - mass spectrometry device based on a microwave plasma torch ion source. Background Art

[0002] Liquid chromatography - mass spectrometry (LC - MS) is a powerful tool that combines two analytical methods of liquid chromatography and mass spectrometry. HPLC - MS can process various types of samples, has qualitative and quantitative analysis capabilities, and its high - efficiency separation ability, high sensitivity, and high selectivity have significant advantages in high - throughput screening and large - scale sample analysis, and is widely used in fields such as drug analysis, environmental monitoring, food safety, and biomarker discovery. Although LC - MS can process various types of samples, for some compounds that are difficult to ionize, its analysis will be limited, and specific sample treatment methods or ionization techniques are required for analysis.

[0003] An open - type ion source is a device used for ionizing samples in mass spectrometry technology. Different from traditional closed - type ion sources, it conducts the ionization process in an open environment. This design makes the open - type ion source have some unique advantages. The emergence of the open - type ion source has greatly expanded the application scope of mass spectrometry technology, especially showing significant advantages in fields such as complex sample analysis, high - throughput screening, and on - line real - time monitoring. With the continuous progress of technology, the application prospect of the open - type ion source in LC - MS will be broader, providing a more efficient and sensitive analysis means for scientific research and practical applications. Summary of the Utility Model

[0004] The utility model provides a liquid chromatography - mass spectrometry device based on a microwave plasma torch ion source. This device can ionize low - polarity compounds through the microwave plasma torch ion source without prior sample pretreatment such as derivatization, solving the problem that conventional liquid chromatography - mass spectrometry instruments cannot analyze low - polarity compounds that are difficult to ionize. This device is convenient to disassemble and assemble, can be exchanged with other ion sources, and broadens the detection range of the liquid chromatography - mass spectrometry instrument.

[0005] A liquid chromatography - mass spectrometry device based on a microwave plasma torch ion source includes:

[0006] A base;

[0007] A microwave plasma generator base and an atomizer base arranged on the base;

[0008] A microwave plasma generator installed on the microwave plasma generator base;

[0009] An atomizer installed on the atomizer base;

[0010] A high - performance liquid chromatography instrument connected to the atomizer;

[0011] A mass spectrometer, the intersection point of the spray outlet of the atomizer and the microwave plasma torch outlet of the microwave plasma generator is directly opposite to the mass spectrometry inlet of the mass spectrometer.

[0012] The gas path outlet of the atomizer and the microwave plasma torch outlet of the microwave plasma generator are on the same horizontal plane as the mass spectrometry inlet of the mass spectrometer.

[0013] The microwave plasma generator includes:

[0014] A microwave generator;

[0015] An inner tube;

[0016] An intermediate tube sleeved on the inner tube;

[0017] And an outer tube sleeved on the intermediate tube;

[0018] The inlet of the inner tube serves as the first inlet of the microwave plasma torch gas path;

[0019] The inlet of the intermediate tube serves as the second inlet of the microwave plasma torch gas path;

[0020] The microwave generator is connected to the inlet of the outer tube through a cable, and the inlet of the outer tube serves as the microwave input port;

[0021] The outlets of the inner tube and the intermediate tube are combined as the microwave plasma torch outlet.

[0022] The atomizer includes:

[0023] A liquid path tube;

[0024] And a gas path tube sleeved on the liquid path tube;

[0025] The inlet of the liquid path tube serves as the liquid path inlet of the atomizer and is connected to the fraction outlet of the high performance liquid chromatograph;

[0026] The inlet of the gas path tube serves as the gas path inlet of the atomizer and is connected to a gas source;

[0027] The outlets of the liquid path tube and the gas path tube are combined to form the spray outlet of the atomizer.

[0028] Furthermore, on the one hand, the microwave plasma torch ion source of the present utility model includes:

[0029] A base module;

[0030] A plasma generator module;

[0031] An atomizer module;

[0032] The base module is fixed on the mass spectrometer and provides a platform for fixing the plasma generator and the nebulizer. The height, the distance from the mass spectrometer, and the lateral angle of the platform can be adjusted.

[0033] The plasma generator module is fixed on the base module. The plasma generator consists of three concentric tubes, namely an argon flow tube (inner tube), an intermediate tube, and a microwave input tube (outer tube). The inner tube and the intermediate tube are the inlets of the plasma generator and are connected with gas pipelines, which are connected to an argon gas cylinder through a rotameter, and the argon gas flow can be controlled simultaneously. The outer tube is connected to the plasma control module, and microwave signals are added to the intermediate tube through a coaxial cable to control the power of the plasma, and the circuit is grounded.

[0034] The nebulizer module is fixed on the base module. The inlet of the nebulizer is connected with a gas pipeline and a liquid pipeline. The gas pipeline is connected to a nitrogen gas cylinder, and the liquid pipeline is connected to a high-performance liquid chromatography to transmit fractions. The outlet of the nebulizer is connected with a gas nozzle and a liquid nozzle. The gas nozzle is wrapped around the liquid nozzle to form a mixed jet.

[0035] On the other hand, the present invention provides a liquid chromatography-mass spectrometry instrument, including the microwave plasma torch ion source described in the foregoing embodiment.

[0036] The microwave plasma generator forms a microwave plasma torch under the condition of introducing sufficient argon gas and a certain voltage. It has a certain distance and a certain angle with the mass spectrometry inlet, and can be freely adjusted according to the sample properties.

[0037] After the sample is separated by high-performance liquid chromatography, it flows into the nebulizer and forms a separated sample spray under a certain atomization gas flow rate. The sample spray is consistent with the above-mentioned microwave plasma torch, has a certain distance and a certain angle with the mass spectrometry inlet, and intersects with the microwave plasma torch at a point and falls in front of the mass spectrometry inlet, and can be freely adjusted according to the sample properties.

[0038] The sample spray is ionized by the microwave plasma torch to form charged solvent ions or analyte ions. The solvent ions can continue to transfer charges with the analyte molecules to form analyte ions, and then enter the mass spectrometer to realize the detection of the analyte ions.

[0039] Compared with the prior art, the present invention has the following advantages:

[0040] 1. By using the detection method provided by the present invention, the synchronous separation and detection of each component in the long-chain linear alkylbenzene mixture can be realized, and the baseline separation degree of each component is high and the sensitivity is high.

[0041] 2. Ionization of long-chain linear alkylbenzene is achieved through a microwave plasma torch ion source, avoiding complex sample pretreatment processes and fully obtaining mass spectra of various types of compounds in the long-chain linear alkylbenzene sample. Description of the Drawings

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments.

[0043] Figure 1 It is a liquid chromatography-mass spectrometry device diagram based on a microwave plasma torch ion source of the present invention.

[0044] Figure 2 It is a top view structural schematic diagram of the plasma generator module of the present invention.

[0045] Figure 3 It is a top view structural schematic diagram of the nebulizing gas module of the present invention.

[0046] The numerical markings in the drawings are respectively:

[0047] 1: Microwave plasma generator; 2: Nebulizer; 3: Microwave plasma generator base; 4: Nebulizer base; 5: Base;

[0048] 10: Microwave plasma torch outlet; 11: Microwave plasma torch gas path inlet (inner tube); 12: Microwave plasma torch gas path inlet (middle tube); 13: Plasma microwave input port (outer tube);

[0049] 20: Nebulizer spray outlet; 21: Nebulizer liquid path inlet; 22: Nebulizer gas path inlet. Detailed Embodiments

[0050] To facilitate the understanding of the present invention, the following will further describe the present invention in detail with reference to the drawings of the specification. However, the protection scope of the present invention is not limited to the following specific embodiments.

[0051] Unless otherwise defined, all professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention.

[0052] The working gas of the plasma torch is argon, which is controlled by a rotameter and the adjustable range is 0 - 2 ml / min. The power is adjustable from 0 to 200 W (the microwave operating frequency is 2.45 GHz). The angle α (30° - 60°) and the distance d 1 (0 - 30 mm) between the plasma torch and the mass spectrometry inlet are adjustable to make it face the mass spectrometer inlet directly.

[0053] The specific model of the high performance liquid chromatograph used in the following examples is Thermo Scientific TM Vanquish TM Liquid chromatograph (Thermo Fisher Scientific, Waltham, MA), and the specific model of the high-resolution orbitrap mass spectrometer used is Thermo LTQ Orbitrap mass spectrometer (Thermo Fisher Scientific, Waltham, MA).

[0054] The mass spectrometry settings are as follows:

[0055] The capillary voltage is set to 30 V; the capillary temperature is set to 300 °C; the lens voltage is set to 100 V; the plasma argon gas flow rate is set to 1.0 mL / min; the plasma power is set to 80 W; control the intersection of the plasma torch and the sample spray at the front end of the mass spectrometry inlet, 3 mm away from the mass spectrometry inlet; adopt the positive ion detection mode. The specific settings are as Figure 1 shown.

[0056] It has been found through research that this liquid chromatography setting has a good separation effect on long-chain linear alkylbenzenes, and this mass spectrometry setting has a good ionization effect on long-chain linear alkylbenzenes.

[0057] Example:

[0058] Combined with Figures 1-3 , the liquid chromatography-mass spectrometry device based on the microwave plasma torch ion source of the present utility model includes: a base 5; a microwave plasma generator base 3 and an atomizer base 4 provided on the base 5; a microwave plasma generator 1 installed on the microwave plasma generator base 3; an atomizer 2 installed on the atomizer base 4; a high performance liquid chromatograph connected to the atomizer 2; a mass spectrometer, and the intersection point of the spray outlet 20 of the atomizer and the microwave plasma torch outlet 10 of the microwave plasma generator 1 is directly opposite to the mass spectrometry inlet of the mass spectrometer. The spray outlet 20 of the atomizer and the microwave plasma torch outlet 10 of the microwave plasma generator 1 and the mass spectrometry inlet of the mass spectrometer are on the same horizontal plane.

[0059] The microwave plasma generator 1 includes: a microwave generator; an inner tube with an inlet of the microwave plasma torch gas path 11; an intermediate tube sleeved on the inner tube with an inlet of the microwave plasma torch gas path 12; and an outer tube sleeved on the intermediate tube with an inlet of the plasma microwave input port 13. The inlet of the inner tube (the microwave plasma torch gas path inlet 11) serves as the first inlet of the microwave plasma torch gas path. The inlet of the intermediate tube (the microwave plasma torch gas path inlet 12) serves as the second inlet of the microwave plasma torch gas path. The microwave generator is connected to the inlet of the outer tube through a cable, and the inlet of the outer tube serves as the microwave input port. The outlets of the inner tube and the intermediate tube are combined as the microwave plasma torch outlet 10. The nebulizer includes: a liquid path tube; and a gas path tube sleeved on the liquid path tube. The inlet of the liquid path tube serves as the liquid path inlet 21 of the nebulizer and is connected to the fraction outlet of the high performance liquid chromatography. The inlet of the gas path tube serves as the gas path inlet 22 of the nebulizer and is connected to a gas source. The outlets of the liquid path tube and the gas path tube are combined to form the spray outlet 20 of the nebulizer.

[0060] Specifically, a liquid chromatography - mass spectrometry instrument includes a base 5 fixed on a mass spectrometer. On the base 5, there are placed a base 3 for fixing the microwave plasma module 1 and a base 4 for fixing the nebulizer module 2. The microwave plasma module 1 is connected to an argon gas cylinder through a rotameter, and the nebulizer 2 is connected to a high performance liquid chromatography and a nitrogen gas cylinder.

[0061] The microwave plasma in the present utility model is mainly used for the ionization of the liquid phase fractions in the liquid chromatography - mass spectrometry instrument to change the ionization form of the liquid phase fractions. The microwave plasma torch has the ionization ability applicable to most compounds. At the same time, the structure of the present utility model is simple, easy to disassemble and assemble, and can be interchanged with other ionization means.

[0062] Specifically, first adjust the angles and distances between the plasma generator 1, the nebulizer 2 and the mass spectrometry inlet on the base module.

[0063] The plasma emission port 10 of the plasma generator 1 and the mass spectrometry inlet should be on the same horizontal plane; the spray outlet 20 of the nebulizer 2 and the mass spectrometry inlet should be on the same horizontal plane.

[0064] The gas path inlets 11, 12 of the plasma generator 1 are connected to the argon gas cylinder through a rotameter, and the gas flow is controlled at 0 - 2 mL / min. The plasma power is adjusted through a controller connected to the microwave input tube, controlled at 0 - 100 W, and the microwave operating frequency is 2.45 GHz.

[0065] Adjust the controller. When the plasma power reaches 80 W, a stable microwave plasma torch can be formed, and at this time, the microwave plasma torch can achieve the ionization of most compounds, including low - polarity compounds.

[0066] Adjust the float flowmeter to control the argon gas flow rate to the gas path inlets 11 and 12 to be 1.0 mL / min. When the argon gas flow rate increases, the microwave plasma torch becomes stable accordingly. When the flow rate is 1.0 mL / min, the microwave plasma torch can maintain a stable state with a certain intensity. When the argon gas flow rate continues to increase, the length of the microwave plasma torch becomes longer.

[0067] Align the front end of the microwave plasma torch with the mass spectrometry inlet, adjust the angle α between the microwave plasma torch and the mass spectrometry inlet to be 30°, and adjust the distance d from the front end to the mass spectrometry inlet 1 , 0 < d 1 ≤ 30 mm, and let d 1 = 3 mm; when d 1 is infinitely close to 0 mm, the microwave plasma torch is likely to contact the mass spectrometry inlet, which may damage the mass spectrometry and cause serious background interference at the same time; when d 1 increases, the background signal decreases; when d 1 increases to 3 mm, the background signal decreases to a relatively small value, and there is no obvious interference to the detection of the sample signal at this time.

[0068] The liquid path inlet 21 of the nebulizer 2 is connected to the fraction outlet of the high-performance liquid chromatography, and the gas path inlet 22 is connected to the nitrogen gas cylinder. Adjust the nitrogen gas flow rate to make the spray outlet 20 present a stable spray. Make the nebulizer spray land on the front end of the microwave plasma torch, with the landing point facing the mass spectrometry inlet, and the distance to the mass spectrometry inlet is controlled at 3 mm.

[0069] After completing the above adjustments to the microwave plasma and the nebulizer, the sample to be tested can be injected and separated by HPLC. The fraction solution is atomized by the nebulizer to form a spray and is pushed to the front end of the microwave plasma torch. The sample solution is ionized by the microwave plasma torch and enters the mass spectrometer. The argon gas flow rate, the microwave plasma power, and the spray landing point position ensure the ionization efficiency of the sample, and the distance between the microwave plasma torch and the mass spectrometry inlet ensures the signal intensity of the sample in the mass spectrometry.

[0070] Based on the microwave plasma, the present utility model can freely set the high-performance liquid chromatography and mass spectrometry used in combination with it, including the combination with multi-dimensional liquid chromatography and multi-stage mass spectrometry. The device of the present experiment is relatively simple, easy to load and unload, and has the feasibility of being used in combination with other analytical methods.

[0071] The utility model relates to a liquid chromatography-mass spectrometry device based on a microwave plasma torch ion source. The device ionizes analytes through the high-temperature thermal desorption of microwave plasma. The high-temperature gas flow and electric field in the ion source improve the detection sensitivity of the device, realizing the direct separation and analysis of various types of compounds, and having the characteristics of high resolution and high-throughput detection of liquid chromatography-mass spectrometry methods. Compared with other liquid chromatography-mass spectrometry methods, the utility model broadens the detection range of samples. The microwave plasma torch can not only be used for the analysis of polar compounds, but also has high ionization efficiency and sensitivity for low-polarity compounds, which is lacking in other liquid chromatography-mass spectrometry instruments. The utility model provides an effective solution for the detection of actual samples with complex matrices and special samples with low polarity, has strong innovation and practical value, the device structure is simple, and provides a reference scheme for further modification.

[0072] The above content is a further detailed description of the utility model in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the utility model is only limited to these descriptions. For those of ordinary skill in the technical field to which the utility model belongs, without departing from the concept, several simple deductions or substitutions can be made, and all should be regarded as belonging to the protection scope of the utility model.

Claims

1. A liquid chromatography-mass spectrometry device based on a microwave plasma torch ion source, characterized in that: include: Base; A microwave plasma generator base and an atomizer base are arranged on the base; A microwave plasma generator installed on the microwave plasma generator base; An atomizer mounted on the atomizer base; a high performance liquid chromatograph connected to the atomizer; A mass spectrometer, wherein the intersection of the gas path outlet of the atomizer and the microwave plasma torch outlet of the microwave plasma generator is directly opposite to the mass spectrometer inlet of the mass spectrometer.

2. The liquid chromatography-mass spectrometry device based on a microwave plasma torch ion source according to claim 1, characterized in that: The gas path outlet of the atomizer and the microwave plasma torch outlet of the microwave plasma generator are on the same horizontal plane as the mass spectrometer inlet of the mass spectrometer.

3. The liquid chromatography-mass spectrometry device based on a microwave plasma torch ion source according to claim 1, characterized in that: The microwave plasma generator comprises: Microwave generator; Inner tube; An intermediate tube sleeved on the inner tube; and an outer tube sleeved on the middle tube.

4. The liquid chromatography-mass spectrometry device based on a microwave plasma torch ion source according to claim 3, characterized in that: The inlet of the inner tube serves as the first inlet of the microwave plasma torch gas path; The inlet of the intermediate tube serves as the second inlet of the microwave plasma torch gas path.

5. The liquid chromatography-mass spectrometry device based on a microwave plasma torch ion source according to claim 3, characterized in that: The microwave generator is connected to the inlet of the outer tube through a cable, and the inlet of the outer tube serves as a microwave input port.

6. The liquid chromatography-mass spectrometry device based on a microwave plasma torch ion source according to claim 3, characterized in that: The outlet of the inner tube and the outlet of the middle tube are combined to serve as the outlet of the microwave plasma torch.

7. The liquid chromatography-mass spectrometry device based on a microwave plasma torch ion source according to claim 1, characterized in that: The atomizer comprises: Liquid line pipe; and a gas line tube sleeved on the liquid line tube.

8. The liquid chromatography-mass spectrometry device based on a microwave plasma torch ion source according to claim 7, characterized in that: The inlet of the liquid circuit tube serves as the liquid circuit inlet of the atomizer and is connected to the fraction outlet of the high performance liquid chromatograph; The inlet of the gas circuit pipe serves as the gas circuit inlet of the atomizer and is connected to the gas source; The outlet of the liquid pipe and the outlet of the gas pipe are combined to form the spray outlet of the atomizer.

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