阅读说明：本技术 一种基于电弧热耦合的可直接分析含盐样品的液质联用的检测方法 (Arc thermal coupling-based LC-MS (liquid chromatography-mass spectrometry) detection method capable of directly analyzing salt-containing sample ) 是由 潘远江 高元吉 陈维伟 于 2021-08-20 设计创作，主要内容包括：本发明公开了一种基于电弧热耦合的可直接分析含盐样品的液质联用的检测方法,包括以下步骤：1)样品雾化：调节液相喷雾发生模块喷雾方向,喷头所指方向为带有尖端的金属热源的尖端,样品被液相色谱分离后进入液相喷雾发生模块的液路管道,从液路喷头流出,雾化气经气路管道从气路喷头112喷出,在雾化气的作用下,液路喷头中的样品雾化成小液滴；2)离子化：被雾化的小液滴喷射在耦合了电弧的带有尖端的金属热源上,带有尖端的金属热源将小液滴电离生成气相离子,进而进入质谱分析,实现带电离子的高效离子化分析。本发明以实现液相色谱联用,将液相色谱高效分离特性与AEAI的高盐耐受特性实现融合。(The invention discloses a liquid chromatography-mass spectrometry detection method capable of directly analyzing a salt-containing sample based on arc thermal coupling, which comprises the following steps of: 1) sample atomization: adjusting the spraying direction of the liquid phase spraying generation module, wherein the direction indicated by the spray head is a tip of a metal heat source with a tip, a sample enters a liquid path pipeline of the liquid phase spraying generation module after being separated by liquid chromatography and flows out of the liquid path spray head, atomized gas is sprayed out of the gas path spray head 112 through the gas path pipeline, and the sample in the liquid path spray head is atomized into small droplets under the action of the atomized gas; 2) ionization: the atomized small liquid drops are sprayed on a metal heat source with a tip, which is coupled with an electric arc, the metal heat source with the tip ionizes the small liquid drops to generate gas-phase ions, and then the gas-phase ions enter mass spectrometry to realize high-efficiency ionization analysis of the charged ions. The invention realizes the combination of liquid chromatography and the fusion of the high-efficiency separation characteristic of the liquid chromatography and the high-salt tolerance characteristic of AEAI.)

1. A detection method for directly analyzing the LC-MS for a salt-containing sample based on arc thermal coupling, which adopts an LC-MS interface device for directly analyzing the salt-containing sample based on arc thermal coupling, comprises the following steps:

a liquid phase spray fixing and control module;

the liquid phase spray generating module is arranged on the liquid phase spray fixing and controlling module;

an arc heat source fixing and controlling module;

the arc generating module and the heat source module are arranged on the arc heat source fixing and controlling module;

the liquid phase spray generation module, the electric arc generation module and the heat source module are arranged around the mass spectrum inlet;

the detection method comprises the following steps:

1) sample atomization: adjusting the spraying direction of the liquid phase spraying generation module, wherein the direction pointed by a spray head is a tip of a metal heat source with a tip, a sample enters a liquid path pipeline of the liquid phase spraying generation module after being separated by liquid chromatography and flows out of the liquid path spray head, atomized gas is sprayed out of a gas path spray head through a gas path pipeline, and the sample in the liquid path spray head is atomized into small droplets under the action of the atomized gas;

2) ionization: the atomized small liquid drops are sprayed on a metal heat source with a tip, which is coupled with an electric arc, and the metal heat source with the tip ionizes the small liquid drops to generate gas-phase ions, so that the gas-phase ions enter mass spectrometry.

2. The arc thermal coupling based detection method for LC-MS capable of directly analyzing salt-containing samples according to claim 1, wherein the liquid phase spray fixing and control module comprises:

a Z-axis moving platform;

the R-axis moving platform is arranged on the Z-axis moving platform;

and the first fixing fitting is arranged on the R-axis moving platform and used for fixing the liquid-phase spray generating module.

3. The arc thermal coupling-based detection method for LC-MS used for direct analysis of salt-containing samples according to claim 2, wherein the first fixed part printing and fixing part comprises a fixed bottom plate and a liquid phase spray fixing plate with holes, the lower surface of the fixed bottom plate is fixedly connected with the upper surface of the R-axis moving platform, and the liquid phase atomizer of the liquid phase spray generation module is installed in the hole of the liquid phase spray fixing plate with holes.

4. The arc thermal coupling based detection method for LC-MS capable of directly analyzing salt-containing samples according to claim 1, wherein the liquid phase spray generation module comprises: the liquid atomizer comprises a gas path pipeline, a liquid path pipeline and a liquid phase atomizer connected with the gas path pipeline and the liquid path pipeline.

5. The detection method for liquid chromatography-mass spectrometry based on arc thermal coupling and capable of directly analyzing salt-containing samples according to claim 4, wherein the liquid phase atomizer comprises a liquid path nozzle, a gas path nozzle, a liquid path pipe interface connected with the liquid path nozzle, and a gas path pipe interface connected with the gas path nozzle; the liquid path pipeline interface is connected with the liquid path pipeline, and the gas path pipeline interface is connected with the gas path pipeline.

6. The arc thermal coupling based detection method for LC-MS capable of directly analyzing salt-containing samples according to claim 1, wherein said arc heat source fixing and controlling module comprises: the device comprises a three-axis moving platform, and an arc fixing accessory and a heat source fixing accessory which are fixed on the three-axis moving platform.

7. The detection method for liquid chromatography-mass spectrometry based on arc thermal coupling and capable of directly analyzing salt-containing samples according to claim 6, wherein the arc fixing fitting is of a cuboid structure, grooves and protrusions are symmetrically arranged on the cuboid structure in pairs, and the lower surface of the arc fixing fitting is fixedly connected with the upper surface of the three-axis moving platform;

the heat source fixing accessory is of a structure with a round hole and a groove, and is tightly sleeved and fixed on the electric arc fixing accessory through the groove structure.

8. The arc thermal coupling-based detection method for LC-MS capable of directly analyzing salt-containing samples according to claim 1, wherein the arc generation module comprises a pulsed arc inversion generator electronic module, and the pulsed arc inversion generator electronic module comprises a voltage conversion circuit, a first discharge needle and a second discharge needle; the first discharge needles are connected with the positive electrode of the voltage conversion circuit, and the second discharge needles are connected with the negative electrode of the voltage conversion circuit.

9. The arc thermal coupling based detection method for LC-MS capable of directly analyzing salt-containing samples according to claim 1, wherein the heat source module comprises: a heat generating and conditioning device and a metal heat source with a tip connected to the heat generating and conditioning device.

10. The arc thermal coupling based detection method for LC-MS capable of directly analyzing salt-containing samples according to claim 9, wherein the metal tip of the metal heat source with tip is placed between the first discharge needle and the second discharge needle.

Technical Field

The invention relates to the technical field of liquid chromatography-mass spectrometry, in particular to a liquid chromatography-mass spectrometry detection method capable of directly analyzing a salt-containing sample based on arc thermal coupling.

Background

Liquid chromatography-mass spectrometry (LC-MS), also known as LC-MS, consists essentially of a liquid chromatograph, an interface device (also an ion source), a mass spectrometer, and a data processing system. The principle is to use the excellent separation ability of liquid chromatography as a separation system, separate samples according to polarity, and then detect different samples using high-sensitivity mass spectrometry. The sample after liquid phase separation is ionized through the action of an ion source, then separated according to the mass-to-charge ratio in a mass analyzer of a mass spectrum, and finally a mass spectrogram is obtained through a detector. The technology combines the advantages of a chromatographic mass spectrometry technology, namely, the chromatogram can quickly, efficiently and accurately separate complex samples according to polarity, and the mass spectrometry has high selectivity and sensitivity and provides relative molecular mass and structural information of an object to be detected. The technology is widely applied to many fields such as biological analysis drug analysis, food analysis, environmental analysis and the like.

In the medical field, biological samples are generally required to be stored in high-salt systems such as buffer salts to maintain physiological activity, and in addition, active ingredients in many medicaments are basic organic matters, and the compounds generally have the phenomena of peak tailing or poor selective separation in reverse phase chromatographic separation, so that a non-volatile buffer or an ion pair reagent is required to be added to a mobile phase. However, these high-salt systems can suppress the signal of the substance to be detected, greatly reducing the sensitivity of mass spectrometry detection, and on the other hand, the salt in the high-salt solution can be deposited in the pipeline, causing the blockage of the sample injection capillary, the taper hole and the like, and bringing serious damage to the instrument. Therefore, high salt samples or samples with high salt buffer salts as the mobile phase generally cannot be directly subjected to mass spectrometry.

Open arc ionization (AEAI, patent No. CN202011289117.8) mass spectrometry technology converts the daily 220V voltage through a circuit, and finally forms an electric arc which breaks through air through two discharge needles, the electric arc forms hydrated ions through electrolyzing trace water in the air, and the hydrated ions are combined with an analyte to enable the analyte to form charged ions to enter the mass spectrometry. The AEAI technology realizes the charged analysis of a sample by forming a single electric arc in the air, and the sample is generally volatilized or evaporated or atomized for sample injection through a disposable quartz capillary or a metal sample injection needle with a larger aperture, so that the problem that a high-salt sample blocks a spray head in the electrospray mass spectrum is solved. Subsequently, we coupled a temperature-controllable metal probe (CN202011395404.7) based on AEAI to further verify the mechanism of desorption ionization. Therefore, the high-salt sample can not directly enter a mass spectrometer vacuum system during sample injection, the components to be analyzed in the sample can be desorbed and analyzed from the sample solution through the thermal desorption effect of the single electric arc, and the sampling cone or the mass analyzer of the mass spectrometer and the like can not be influenced. However, the flow rate used by the general high performance liquid chromatography is 0.8-1.5 mL/min, even if the ultra high performance liquid chromatography is adopted, the common working flow rate is 0.2-0.8 mL/min, and the quenching of the single arc can be caused by directly aligning the outlet of the chromatography with the single arc without additional design. Therefore, the ionization technology based on the electric arc is further butted with a liquid phase passage, so that the ionization technology is used as a liquid phase mass spectrum coupling interface.

Disclosure of Invention

The invention provides a liquid chromatography-mass spectrometry detection method capable of directly analyzing a salt-containing sample based on arc thermal coupling, which is used for realizing liquid chromatography-mass spectrometry and fusing the high-efficiency separation characteristic of liquid chromatography and the high-salt tolerance characteristic of AEAI.

The invention provides a liquid chromatography-mass spectrometry interface device capable of directly analyzing a salt-containing sample based on arc thermal coupling, which comprises:

a liquid phase spray fixing and control module;

the liquid phase spray generating module is arranged on the liquid phase spray fixing and controlling module;

an arc heat source fixing and controlling module;

the arc generating module and the heat source module are arranged on the arc heat source fixing and controlling module;

the liquid phase spray generation module, the electric arc generation module and the heat source module are arranged around the mass spectrum inlet.

The liquid phase spray fixing and control module comprises:

a Z-axis moving platform;

the R-axis moving platform is arranged on the Z-axis moving platform;

and the first fixing fitting is arranged on the R-axis moving platform and used for fixing the liquid-phase spray generating module.

The Z-axis moving platform can move along the vertical direction. The R-axis moving platform is used for making circular motion on a horizontal plane. The upper surface of the Z-axis moving platform is fixedly connected with the lower surface of the R-axis moving platform; the first fixing fitting (i.e., the first 3D printing fixing fitting) includes a fixing base plate and a liquid phase spray fixing plate having a hole; the lower surface of the fixed bottom plate is fixedly connected with the upper surface of the R-axis moving platform. The liquid phase atomizer of the liquid phase spray generating module is arranged in the hole of the liquid phase spray fixing plate with the hole.

The fixed bottom plate is of a disc-shaped structure printed by 3D, the height is h1, and h1 is more than or equal to 8mm and less than or equal to 10 mm; the upper surface of the disc of the fixed bottom plate can be additionally provided with a cuboid structure;

the liquid phase spraying fixing plate with the holes is fixed on the fixed bottom plate through a slideway structure, and the set distance from the liquid phase spraying fixing plate with the holes to the circle center of the fixed bottom plate can be adjusted within the range of 0mm to 40 mm.

The angle formed by the axial direction of the liquid phase spraying fixing plate with the hole and the horizontal direction of the mass spectrum inlet can be adjusted within the range of 0-90 degrees through the R-axis moving platform.

The liquid phase spray generating module comprises: the liquid atomizer comprises a gas path pipeline, a liquid path pipeline and a liquid phase atomizer connected with the gas path pipeline and the liquid path pipeline, wherein the angle between the gas path pipeline and the liquid path pipeline is alpha, and the alpha is 90 degrees; the liquid phase atomizer is of a T-shaped structure, one end of the liquid phase atomizer is used for being connected with a liquid phase, the other end of the liquid phase atomizer is used for being connected with atomizing gas, and the other end of the liquid phase atomizer is used for generating liquid phase spray.

The liquid phase atomizer comprises a liquid path spray head, a gas path spray head, a liquid path pipeline interface connected with the liquid path spray head and a gas path pipeline interface connected with the gas path spray head; the liquid path pipeline interface is connected with the liquid path pipeline, and the gas path pipeline interface is connected with the gas path pipeline. The protruding length of the outlet end of the liquid path spray head is a, and a is more than or equal to 0mm and less than or equal to 1 mm; the liquid path spray head and the gas path spray head are of coaxial circular tube structures; the liquid pipeline joint is of a metal pipe structure, the inner diameter is d1, and d1 is more than or equal to 0.5mm and less than or equal to 1 mm; the outer diameter is d2, d2 is more than or equal to 1mm and less than or equal to 1.5 mm; the gas path pipeline interface is of a metal pipe structure with a nut for fixing, the inner diameter is d3, and d3 is more than or equal to 5.5mm and less than or equal to 6 mm; the outer diameter is d4, d4 is more than or equal to 7mm and less than or equal to 7.5 mm.

The liquid phase solution flows through the liquid phase atomizer through the liquid path pipeline interface through the liquid path pipeline and reaches the liquid path spray head; the atomized gas flows through the liquid phase atomizer through a gas path pipeline interface through a gas path pipeline vertical to the liquid path pipeline and reaches the gas path spray head; the liquid phase solution is blown and atomized by the atomizing gas in the concentric gas path spray head at the liquid path spray head.

The liquid phase atomizer coaxially penetrates through the small hole of the liquid phase spray fixing plate with the hole and is tightly sleeved; one end of the liquid phase pipeline is tightly sleeved with the liquid phase atomizer through a liquid pipeline interface, and the other end of the liquid phase pipeline is connected with the high performance liquid chromatography outlet through a metal two-way. One end of the gas path pipeline is tightly sleeved with the liquid phase atomizer through a gas path pipeline interface and is fixed by a nut, and the other end of the gas path pipeline is tightly sleeved with the gas outlet of the nitrogen steel cylinder and is fixed by a nut.

The arc heat source fixing and controlling module comprises: a three-axis moving platform, and an arc fixing part and a heat source fixing part which are fixed on the three-axis moving platform,

the arc fixing accessory is of a 3D printed cuboid structure, grooves and protrusions which are symmetrical in pairs are formed in the cuboid structure, and the lower surface of the cuboid structure is fixedly connected with the upper surface of the three-axis mobile platform;

the heat source fixing accessory is of a structure with a round hole and a groove, and is tightly sleeved and fixed on the electric arc fixing accessory through the groove structure.

The arc generation module comprises a pulse arc inversion generator electronic module, a voltage-adjustable power adapter and a DC female-to-crocodile clip conversion power line; the pulse arc inversion generator electronic module comprises a voltage conversion circuit, a first discharge needle and a second discharge needle; the first discharge needles are connected with the positive electrode of the voltage conversion circuit, and the second discharge needles are connected with the negative electrode of the voltage conversion circuit. The distance between the first discharge needle and the second discharge needle is b, and b is more than or equal to 10mm and less than or equal to 15 mm.

The voltage-adjustable power adapter is connected with a national standard 220V voltage source, and the output voltage of the voltage-adjustable power adapter is continuously, stably and adjustably within the range of 3V to 24V;

and the pulse arc inversion generator electronic module is connected with the adjustable voltage power adapter through a DC female head-to-crocodile clip conversion power line.

The pulse arc inversion generator electronic module is tightly sleeved on the arc fixing accessory through a raised cuboid structure on the arc fixing accessory.

The heat source module includes: the device comprises a heat generating and adjusting device and a metal heat source with a sharp end, wherein the metal heat source is connected with the heat generating and adjusting device; the heat generating and adjusting device can adjust the temperature of the metal heat source with the tip to be continuously adjustable within the range of 100-500 ℃;

the metal heat source with the tip, the types of the metal heat source tip include but are not limited to: type I, type B/LB, type D/LD, type C/CF, type K, type H.

The metal heat source with the tip passes through the round hole on the heat source fixing accessory and is tightly sleeved; the metal tip of the metal heat source with the tip is placed between the first discharge needle and the second discharge needle.

The liquid phase spray generation module atomizes and sprays the liquid phase sample on the tip of the metal heat source coupled with the electric arc. The metal heat source tip can not fluctuate due to the large volume and high flow speed of a liquid phase sample, and is more stable relative to a single electric arc. The atomized droplets contact the metal tip to which the arc is applied and are desorbed from the solution by thermal desorption. The arc is coupled to the metal tip and the plasma jet generated by the arc can be regarded as a charge generator which continuously provides charges to the heat source tip, so that the metal heat source becomes a conductor with charge equipotential distribution, and the charges have the highest density at the tip. When the small liquid drops of the object to be detected impact the surface of the heat source tip, free charges in the heat source tip escape from the tip through the photoelectric effect, charge transfer and other modes, so that the object to be detected is ionized and then enters mass spectrometry for analysis.

The arc generation module is one of important modules for realizing sample separation, and comprises a pulse arc inversion generator electronic module and a voltage-adjustable power adapter; the DC female head is converted into the crocodile clip to convert the power line. The pulse arc inversion generator electronic module comprises a voltage conversion circuit, a first discharge needle and a second discharge needle; the first discharge needle is connected with the positive electrode of the voltage conversion circuit, and the second discharge needle is connected with the negative electrode of the voltage conversion circuit; the voltage-adjustable power adapter is connected with a national standard 220V voltage source; and the pulse arc inversion generator electronic module is connected with the adjustable voltage power adapter through a DC female head-to-crocodile clip conversion power line.

The heat source module includes: a heat generating and regulating device, a metal heat source with a tip;

the types of metal heat source tips with tips include, but are not limited to: type I, type B/LB, type D/LD, type C/CF, type K, type H. The metal heat source with the tip passes through the round hole on the heat source fixing accessory and is tightly sleeved; the metal tip of the metal heat source with the tip is placed between the first discharge needle and the second discharge needle.

Voltage is loaded between the first discharge needle and the second discharge needle through the adjustable power adapter, the DC female head-to-crocodile clip conversion power line and the pulse arc inversion generator electronic module, and when the voltage reaches a certain value, an arc capable of puncturing air can be generated. The pointed metal heat source is capable of conducting electricity such that an arc is coupled to the pointed metal heat source disposed between the first discharge needle and the second discharge needle.

Further, the voltage connected with the adjustable power adapter is 220V in national standard, and the voltage loaded on the electronic module of the pulse arc inversion generator is adjusted to be continuously adjustable within the range of 3V to 24V by adjusting the adjustable power adapter.

Furthermore, the distance between the first discharge needle and the second discharge needle is b, b is more than or equal to 10mm and less than or equal to 15mm, the voltage is changed, and the distance can be further adjusted.

Further, the heat source generating and adjusting device can adjust the temperature of the metal heat source with the tip to be continuously adjustable within the range of 100 ℃ to 500 ℃, and can realize quick and stable set temperature.

Further, the flow rate of the gas connected with the liquid phase spray generating module is continuously adjustable within the range of 1L/min to 5L/min, and the degree and the speed of sample spraying are adjusted by adjusting the flow rate of the gas loaded on the liquid phase spray generating module.

Furthermore, the liquid phase spray fixing and control module can adjust the spray direction, and the angle beta formed by the spray direction and the horizontal direction of the mass spectrum inlet is more than or equal to 0 degree and less than or equal to 90 degrees;

furthermore, the liquid phase spray fixing and control module can adjust the distance between a spray outlet and a mass spectrum inlet, the distance between the spray outlet and the mass spectrum inlet is d, and d is more than or equal to 0mm and less than or equal to 40 mm.

Furthermore, the protruding length of the outlet end of the liquid path spray head is a, and a is more than or equal to 0mm and less than or equal to 1 mm;

furthermore, the liquid pipeline joint is of a metal pipe structure, the inner diameter is d1, and d1 is more than or equal to 0.5mm and less than or equal to 1 mm; the outer diameter is d2, d2 is more than or equal to 1mm and less than or equal to 1.5 mm; the gas path pipeline interface is of a metal pipe structure with a nut for fixing, the inner diameter is d3, and d3 is more than or equal to 5.5mm and less than or equal to 6 mm; the outer diameter is d4, d4 is more than or equal to 7mm and less than or equal to 7.5 mm.

The invention also provides a use method of the interface device for the LC-MS capable of directly analyzing the salt-containing sample based on the arc thermal coupling (namely a detection method for the LC-MS capable of directly analyzing the salt-containing sample based on the arc thermal coupling), which comprises the following steps:

1) sample atomization: adjusting the spraying direction of the liquid phase spraying generation module, wherein the direction indicated by the spray head is a tip of a metal heat source with a tip, a sample enters a liquid path pipeline of the liquid phase spraying generation module after being separated by liquid chromatography and flows out of the liquid path spray head, atomized gas is sprayed out of the gas path spray head 112 through the gas path pipeline, and the sample in the liquid path spray head is atomized into small droplets under the action of the atomized gas;

2) ionization: the atomized small liquid drops are sprayed on a metal heat source with a tip, which is coupled with an electric arc, the metal heat source with the tip ionizes the small liquid drops to generate gas-phase ions, and then the gas-phase ions enter mass spectrometry to realize high-efficiency ionization analysis of the charged ions.

Compared with the prior art, the invention has the following advantages:

1) the invention provides a salt-tolerant interface device which can realize the combination of liquid chromatography and mass spectrometry;

2) the invention solves the problems that deposited salt blocks a capillary tube and a sampling cone, simultaneously enhances the detection sensitivity of the mass spectrum to a target compound in a high-salt matrix, and realizes the liquid chromatography-mass spectrum coupling technology under the condition that a sample contains a high-salt buffer salt solution;

3) the invention has the characteristics of rapid and stable sample detection and simple instrument construction.

Drawings

FIGS. 1 and 2 are device diagrams of the interface for salt-tolerant liquid chromatography mass spectrometry based on thermal coupling arc according to the present invention;

FIG. 3 is a schematic diagram of a liquid phase spray generation module;

FIG. 4 is a mass spectrum of the device of the present invention and a conventional electrospray ionization (ESI) probe device for detecting the dissolution of testosterone methyl into sodium chloride solutions of different concentrations;

FIG. 5 is a mass spectrum of the device of the present invention and a conventional electrospray ionization (ESI) probe device for detecting the dissolution of testosterone methyl in lithium chloride solutions of different concentrations;

FIG. 6 is a mass spectrogram of the device for detecting rhodamine B dissolved in different buffer solutions: FIG. 6(a) is a PBS buffer solution; (b) is a Tris-acetate buffer solution; (c) is a citrate buffer solution; (d) is MES buffer solution; (e) is Tricine buffer solution;

FIG. 7 is a mass spectrum of the device of the present invention for detecting the dissolution of reserpine in different types of buffer solutions: FIG. 6(a) is a PBS buffer solution; (b) is a Tris-acetate buffer solution; (c) is a citrate buffer solution; (d) is MES buffer solution; (e) is Tricine buffer solution;

FIG. 8 is a mass spectrum of the device of the present invention for detecting erythromycin dissolved in different buffer solutions: FIG. 6(a) is a PBS buffer solution; (b) is a Tris-acetate buffer solution; (c) is a citrate buffer solution; (d) is MES buffer solution; (e) is Tricine buffer solution;

wherein the numerical designations in the drawings are respectively:

1: a liquid phase spray generation module; 2: a liquid phase spray fixing and control module; 3: an arc generation module; 4: a heat source module; 5: an arc heat source fixing and controlling module;

11: a liquid phase atomizer; 12: a gas path pipeline; 13: a liquid path conduit;

21: a Z-axis moving platform; 22: an R-axis moving platform; 23: 3D prints fixed part 1

31: a pulsed arc inverter generator electronics module; 32: a voltage adjustable power adapter; 33: the DC female head is converted into a crocodile clip conversion power line;

41: a heat source generating and regulating device; 42: a metal heat source with a tip;

51: a three-axis mobile platform; 52: 3D printing of the fixed part 2;

111: a liquid path spray head; 112: a gas circuit nozzle; 113: a liquid line pipe interface; 114: a gas path pipe interface; 231: fixing the bottom plate; 232: a liquid phase spray fixing plate with holes; 311: a voltage conversion circuit; 312: a first discharge needle; 313: a second discharge needle; 521: an arc fixation fitting; 522: the heat source fixing fittings.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. It is to be noted that the following examples are intended to facilitate the understanding of the present invention, and do not set forth any limitation thereto.

First, experimental operation

As shown in fig. 1 and 2, an interface device for mass spectrometry based on arc thermal coupling and capable of directly analyzing a sample containing salt mainly comprises: the device comprises a liquid phase spray generating module 1, a liquid phase spray fixing and controlling module 2, an electric arc generating module 3, a heat source module 4 and an electric arc heat source fixing and controlling module 5; the liquid phase spray generating module 1 comprises a liquid phase atomizer 11, a gas path pipeline 12 and a liquid path pipeline 13; one end of the liquid path pipeline 13 is communicated with the liquid phase atomizer 11, and the other end is communicated with the liquid phase chromatogram; one end of the gas path pipeline 12 is communicated with the liquid phase atomizer 11, and the other end is connected with the atomizing gas; the outlet end of the liquid path spray head 111 transversely protrudes 0mm to 1mm more than the outlet end of the gas path spray head 112;

the liquid phase fixing and controlling module 2 comprises a Z-axis moving platform 21 and an R-axis moving platform 22; the 3D printing fixing fitting 23 (i.e., a first 3D printing fixing fitting) is composed of a fixing base plate 231 and a liquid phase spraying fixing plate 232 with holes, and the liquid phase spraying fixing plate 232 with holes is vertically and tightly sleeved on the fixing base plate 231 through a slide structure; the liquid phase atomizer 11 is tightly sleeved on the liquid phase spray fixing plate 232 with the hole through the round hole.

The upper surface of the Z-axis moving platform 21 is fixedly connected with the lower surface of the R-axis moving platform 22; the 3D printing fixing part 23 is composed of a fixing bottom plate 231 and a liquid phase spraying fixing plate 232 with a hole; the lower surface of the fixed bottom plate 231 is fixedly connected with the upper surface of the R-axis moving platform 22; the fixed bottom plate 231 is of a disc-shaped structure printed by 3D, the height is h1, and h1 is more than or equal to 8mm and less than or equal to 10 mm; the upper surface of the disc of the fixed bottom plate 231 can be additionally provided with a cuboid structure; the liquid phase spray fixing plate 232 with holes is fixed on the fixing bottom plate 231 through a slide structure, and the liquid phase spray fixing plate 232 with holes can be adjusted to a set distance of the circle center of the fixing bottom plate 231 within the range of 0mm to 40 mm. The perforated liquid phase spray fixing plate 232 can adjust the angle formed by the axial direction of the perforated liquid phase spray fixing plate 232 and the horizontal direction of the mass spectrometer inlet within the range of 0 to 90 degrees by the R-axis moving stage 22.

The liquid phase spray generating module 1 comprises a liquid phase atomizer 11, a gas path pipeline 12 and a liquid path pipeline 13, wherein the angle between the gas path pipeline 12 and the liquid path pipeline 13 is alpha which is 90 degrees; the liquid phase atomizer 11 is a T-shaped structure, one end of which is used for connecting a liquid phase, the other end of which is used for connecting atomizing gas, and the other end of which is used for generating liquid phase spray. The liquid phase atomizer 11 comprises a liquid path nozzle 111, a gas path nozzle 112, a liquid path pipeline interface 113 and a gas path pipeline interface 114, wherein the protruding length of the outlet end of the liquid path nozzle is a, and a is more than or equal to 0mm and less than or equal to 1 mm;

the liquid path spray head 111 and the gas path spray head 112 are of a coaxial circular tube structure; the liquid pipeline interface is of a metal pipe structure, the inner diameter is d1, and d1 is more than or equal to 0.5mm and less than or equal to 1 mm; the outer diameter is d2, d2 is more than or equal to 1mm and less than or equal to 1.5 mm; the gas path pipeline interface is a metal pipe structure with a nut for fixing, the inner diameter is d3, and d3 is more than or equal to 5.5mm and less than or equal to 6 mm; the outer diameter is d4, d4 is more than or equal to 7mm and less than or equal to 7.5 mm; the liquid phase solution flows through the liquid phase atomizer 11 through the liquid channel pipeline interface 113 via the liquid channel pipeline 13 and reaches the liquid channel nozzle 111;

the atomized gas flows through the liquid phase atomizer 11 through the gas path pipeline interface 114 via the gas path pipeline 12 perpendicular to the liquid path pipeline, and reaches the gas path nozzle 112; the liquid phase solution is blown and atomized by the atomizing gas in the concentric gas path nozzle 112 in the liquid path nozzle 111. The liquid phase atomizer 11 coaxially penetrates through the small hole of the liquid phase spray fixing plate 232 with the hole and is tightly sleeved; one end of the liquid phase pipeline 13 is tightly sleeved with the liquid phase atomizer 11 through a liquid pipeline interface 113, and the other end of the liquid phase pipeline is connected with the high performance liquid chromatography outlet through a metal two-way. One end of the gas pipeline 12 is tightly sleeved with the liquid phase atomizer 11 through a gas pipeline interface 114 and fixed by a nut, and the other end is tightly sleeved with the gas outlet of the nitrogen steel cylinder and fixed by a nut.

The arc generation module 3 comprises a pulse arc inversion generator electronic module 31, a voltage-adjustable power adapter 32 and a DC female-to-crocodile clip conversion power line 33; the adjustable voltage power adapter 32 is connected with a national standard 220V power supply, and the output voltage of the adjustable voltage power adapter 32 is continuously adjustable within the range of 3V to 24V; the pulsed arc inversion generator electronic module 31 is connected to the adjustable voltage power adapter 21 via a DC female-to-alligator clip switching power cord 33. Pulsed arc inverter generator electronics module 31 includes voltage conversion circuit 311; the first discharge needles 312; the first discharge needle 312 is connected with the positive electrode of the voltage conversion circuit 311, and the second discharge needle 313 is connected with the negative electrode of the voltage conversion circuit 311; the distance between the first discharge needle 312 and the second discharge needle 313 is b, and b is more than or equal to 10mm and less than or equal to 15 mm. The pulse arc inversion generator electronic module 31 is tightly sleeved on the arc fixing fitting through a raised cuboid structure on the arc fixing fitting 521.

The heat source module 4 comprises a heat source generating and regulating device 41, a metal heat source 42 with a tip; the types of metal heat sources 42 with tips include, but are not limited to: type I, type B/LB, type D/LD, type C/CF, type K, type H. The heat generating and regulating device 41 is capable of regulating the temperature of the metal heat source 42 with a tip continuously adjustable within the range of 100 ℃ to 500 ℃. The metal heat source 42 with the tip passes through the round hole on the heat source fixing fitting 522 and is tightly sleeved; the metal tip of the metal heat source 42 with a tip is placed between the first discharge needle 312 and the second discharge needle 313.

The arc heat source fixing and controlling module 5 includes a three-axis moving platform 51, a 3D printing fixing accessory (i.e., a second 3D printing fixing accessory) 52; the 3D printing fixing fitting 52 includes an arc fixing fitting 521, a heat source fixing fitting 522; the lower surface of the arc fixing fitting 521 is fixed on the upper surface of the triaxial moving platform 51; arc mounting fitting 521 is the cuboid structure that 3D printed, and the cuboid structure is last to have two bisymmetry recesses and arch, and its lower surface is connected with triaxial moving platform 51 upper surface fixed. The heat source fixing fitting 522 is vertically and tightly sleeved on the arc fixing fitting 521 through a groove structure; the pulse arc inversion generator electronic module 31 is tightly sleeved on the arc fixing accessory 521 through a convex structure; the metal heat source 42 with a tip is tightly sleeved on the heat source fixing fitting 522 through a round hole.

The use method of the interface device for liquid chromatography-mass spectrometry based on arc thermal coupling and capable of directly analyzing salt-containing samples comprises the following steps:

1) sample atomization: adjusting the spraying direction of the liquid phase spraying generation module 1, wherein the direction pointed by a spray head is the tip of a metal heat source 42 with a tip; after being separated by liquid chromatography, a sample enters a liquid path pipeline 13 of the liquid phase spray generation module 1 and flows out of a liquid path spray head 111, atomized gas is sprayed out of a gas path spray head 112 through a gas path pipeline 12, and under the action of the atomized gas, the sample in the liquid path spray head is atomized into small droplets;

2) ionization: the atomized small liquid drops are sprayed on a metal heat source with a tip, which is coupled with an electric arc, and the metal heat source with the tip ionizes the small liquid drops to generate gas-phase ions, so that the gas-phase ions enter mass spectrometry.

Example analysis

Example 1:

to test the effectiveness of the invention, a comparative experimental study of high-salt methadone was conducted using the apparatus provided in experimental procedure 1 and an ultimate UPLC/LTQ Orbitrap mass spectrometer (seidel feishale, usa).

1. Experimental Material

1.1 analyte to be detected

Medroxytestosterone standard (analytically pure, Hangzhou Chentong materials Co., Ltd.), lot number: m832366. Firstly, methanol is used for preparing 1mg/mL mother liquor, the mother liquor is placed in a refrigerator for proper storage, and methanol is used for diluting the mother liquor to a proper concentration for experiments.

1.2 methanol salt solution

Weighing 5g of sodium chloride (analytically pure, Roen chemical Co., Ltd., Hangzhou city), adding 100mL of high-purity water for dissolving, then adding 400mL of methanol, and ultrasonically mixing for 30min to finally obtain a 1% sodium chloride methanol solution.

Weighing 5g of lithium chloride (analytically pure, Hangzhou Bang chemical industry Co., Ltd.), adding 100mL of high-purity water for dissolving, then adding 400mL of methanol, and ultrasonically mixing for 30min to finally obtain a 1% sodium chloride methanol solution.

2 method of experiment

A chromatographic column: YMC Triart-C18, 4.6X 150mm, 3 μm

Mobile phase: isocratic elution was used: 100% D in 0-3 min; phase D is methanol; column temperature: 25 ℃; flow rate: 1 mL/min; sample introduction amount: 10 μ L.

Mass spectrum conditions:

a positive ion detection mode; the scanning mode is positive ion FULL SCAN (FULL SCAN)

AEAI ion source parameters: arc voltage: 5 kV; flow rate of atomizing gas: 3L/min; temperature of heat source: 300 ℃;

ESI ion source parameters: flow rate of sheath gas: 6 arb; the electrospray voltage is 5 kV; the capillary temperature was 275 ℃.

3. Results of the experiment

In order to more directly observe the salt tolerance effect (hereinafter referred to as STCAI) of the device provided by the invention, the salt tolerance effect of STCAI is observed by comparing the absolute intensity comparison test of the STCAI and ESI devices scanning Mesterlone (Mesterlone) under sodium chloride solutions with different concentrations, and as can be seen from Table 2, in the STCAI device, [ Mesterolone + H]⁺Is much larger than the ESI device. In addition, the total mass spectrum scan of the ordinary ESI is very obvious [ Mesterolone + Na]⁺Ion peak, and in the mass spectrum measured using the present invention, Na⁺The signal of the addend peak is weak.

TABLE 1 mean signal intensity of Methyltestosterone by ESI and STCAI in sodium chloride solutions of different concentrations

Meanwhile, the absolute strength contrast test of the testosterone methy under the lithium chloride solutions with different concentrations scanned by the STCAI device and the ESI device is compared, the salt tolerance effect of the STCAI is observed, and as can be seen from the table 2, in the STCAI device, [ Mesterone + H]⁺Is much larger than the ESI device. In addition, the total mass spectrum scan of the ordinary ESI is very obvious [ Mesterolone + Li]⁺Peak of ion, and intensity ratio [ Mesterolone + H]⁺And higher. In the mass spectrum measured by the method, Li⁺The signal of the addend peak is weak. Namely, the detection of the metandienone can be realized by using the device, and the device is not influenced by a salt solution. The results of this experiment demonstrate that the source of sodium ions in the system of the present invention is primarily a salt-containing solution.

TABLE 2 mean signal intensity of Testosterone Medrogen by ESI and STCAI in lithium chloride solutions of different concentrations

Example 2

To further test the effectiveness of the present invention, rhodamine b (rhodamine) in the buffered salt system was investigated experimentally using the apparatus provided in experimental procedure 1 and an ultimate UPLC/LTQ Orbitrap mass spectrometer (seidel feishale, usa).

1. Experimental Material

1.1 analyte to be detected

Rhodamine B standard (analytically pure, hangzhou bang yi chemical ltd), lot number: r006869. Firstly, methanol is used for preparing 1mmol/L mother liquor, the mother liquor is placed in a refrigerator for proper storage, and methanol is used for diluting to a proper concentration for experiments.

1.2 buffer salt solution

Measuring 10mL of PBS (pH 7) with the concentration of 1mol/L (analytically pure, Hangzhou Pont chemical engineering Co., Ltd.), adding 90mL of high-purity water for dissolving, and ultrasonically mixing for 30min to obtain 100mmol/L PBS.

Measuring 10mL of Tris-acetate buffer solution (analytically pure, Hangzhou Pont chemical industry Co., Ltd.) with the pH of 7 and the concentration of 1mol/L, adding 90mL of high-purity water for dissolving, and ultrasonically mixing for 30min to prepare 100mmol/L Tris-acetate buffer solution.

Measuring 10mL of MES buffer solution (analytically pure, Hangzhou Pont chemical engineering Co., Ltd.) with pH of 7 and concentration of 1mol/L, adding 90mL of high-purity water for dissolving, and ultrasonically mixing for 30min to obtain 100mmol/L MES buffer solution.

Measuring 10mL of 1mol/L Tricine buffer solution (analytically pure, Hangzhou Pont chemical engineering Co., Ltd.) with pH of 7, adding 90mL of high-purity water for dissolving, and ultrasonically mixing for 30min to obtain 100mmol/L Tricine buffer solution.

Measuring 10mL of citrate buffer solution (analytically pure, Hangzhou Pont chemical engineering Co., Ltd.) with pH of 7 and concentration of 1mol/L, adding 90mL of high-purity water for dissolving, and ultrasonically mixing for 30min to obtain 100mmol/L citrate buffer solution.

2 method of experiment

0.5mL of 1mmol/L rhodamine B is aspirated and added to 4.5mL of methanol to make a 100. mu. mol/L standard solution.

And sucking 500 mu L of rhodamine B standard solution and 500 mu L of buffer solution to mix for experiment.

Mass spectrum conditions:

a positive ion detection mode; the scanning mode is positive ion FULL SCAN (FULL SCAN)

STCAI ion source parameters: arc voltage: 5V, and (5); flow rate of atomizing gas: 3L/min; temperature of heat source: at 300 ℃.

3. Results of the experiment

As can be seen from table 3, it is,in an STCAI device, [ Rhodamine + H ]]⁺The ion peak has stronger response signals in five buffer salt systems.

TABLE 3 Signal intensity of rhodamine B in different kinds of buffered saline solutions

Buffer salt solution species	Average signal strength
		PBS buffer	8.65E1
Tris-acetate buffer	3.68E3
		Citrate buffer	4.58E3
MES buffer	1.01E4
		Tricine buffer	1.92E3

Example 4

To further test the effectiveness of the present invention, Reserpine (Reserpine) in buffered salt systems was experimentally studied using the apparatus provided in Experimental procedure 1 and an ultimate UPLC/LTQ Orbitrap Mass spectrometer (Seimer Feishale, USA).

1. Experimental Material

1.1 analyte to be detected

Reserpine standard (analytically pure, Hangzhou bang chemical industry Co., Ltd.), batch number: r006853. Preparing 1mmol/L mother liquor with acetone, storing in refrigerator, and diluting with acetone to appropriate concentration for experiment.

1.2 buffer salt solution

The buffer salt solution was prepared in the same manner as in example 2.

2 method of experiment

0.5mL of 1mmol/L reserpine was aspirated and added to 4.5mL of acetone to make a 100. mu. mol/L standard solution.

Aspirate 500. mu.L of reserpine standard solution and 500. mu.L of buffer solution to mix for testing.

Mass spectrum conditions:

a positive ion detection mode; the scanning mode is positive ion FULL SCAN (FULL SCAN)

STCAI ion source parameters: arc voltage: 5V, and (5); flow rate of atomizing gas: 3L/min; temperature of heat source: at 300 ℃.

3. Results of the experiment

As can be seen from Table 4, in the STCAI apparatus, [ Rerserpine + H ]]⁺The ion peak has stronger response signals in five buffer salt systems.

TABLE 4 Signal Strength of reserpine in different kinds of buffered saline solutions

Buffer salt solution species	Average signal strength
		PBS buffer	2.65E2
Tris-acetate buffer	5.61E2
		Citrate buffer	6.33E2
MES buffer	1.09E3
		Tricine buffer	1.17E3

Example 5

To test the effectiveness of the present invention, an experimental study of Erythromycin (Erythromycin) in a buffer system was performed using the apparatus provided in experimental procedure 1 and an ultimate UPLC/LTQ Orbitrap mass spectrometer (seidel, usa).

1. Experimental Material

1.1 analyte to be detected

Erythromycin standard (analytically pure, Hangzhou bang Yi chemical Co., Ltd.), batch number: r016748. Firstly, methanol is used for preparing 1mmol/L mother liquor, the mother liquor is placed in a refrigerator for proper storage, and methanol is used for diluting to a proper concentration for experiments.

1.2 buffer salt solution

The buffer salt solution was prepared in the same manner as in example 2.

2 method of experiment

0.5mL of 1mmol/L erythromycin was aspirated and added to 4.5mL of methanol to make a 100. mu. mol/L standard solution.

Pipette 500. mu.L of erythromycin standard solution and 500. mu.L of buffer solution to mix for the experiment.

Mass spectrum conditions:

a positive ion detection mode; the scanning mode is positive ion FULL SCAN (FULL SCAN)

STCAI ion source parameters: arc voltage: 5V, and (5); flow rate of atomizing gas: 3L/min; temperature of heat source: at 300 ℃.

3. Results of the experiment

As can be seen from Table 5, [ Erythromycin + H ] in the STCAI device⁺]The ion peak has stronger response signals in five buffer salt systems.

TABLE 5 Signal intensity of erythromycin in different kinds of buffered saline solutions

Buffer salt solution species	Average signal strength
		PBS buffer	8.05E2
Tris-acetate buffer	1.06E2
		Citrate buffer	4.50E2
MES buffer	8.27E2
		Tricine buffer	2.85E3

Conclusion III

Compared with the conventional electrospray ionization mass spectrometry ion source, the device has good salt tolerance, can be combined with liquid chromatography, can simultaneously exert the high-efficiency separation characteristic of the liquid chromatography and the salt tolerance characteristic of AEAI, and provides a good solution for the analysis of high-salt and complex matrix samples. The above-described embodiments should not be construed as limiting the scope of applicability of the present invention, which is defined by the appended claims, any modification which comes within the scope of the invention being covered thereby.