TWI442438B - Airborne Atmospheric Chemical Free Radiator and Mass Spectrometer Analysis System Using the Free Device - Google Patents

Description

Gas shielded atmospheric pressure chemical free device and mass spectrometry system using the same

The present invention relates to a free device for a mass spectrometer, and more particularly to a free device for ionizing a gaseous analyte molecule using a plasma. The invention also relates to a mass spectrometry system employing the free device.

Since 1991, Liquid Chromatography-Mass Spectrometer (LC/MS) has become one of the most important analytical instruments for analyzing biological samples. Due to its high sensitivity and high selectivity, LC/MS is widely used in the analysis of antibiotics, preservatives, pesticide residues, growth hormones and harmful additives in foods; drug metabolism and pharmacokinetics in drug research. And in vitro analysis of drugs and their metabolites; medical screening and health checks; and scientific testing of drugs.

The liquid chromatography mass spectrometer (LC/MS) mainly comprises a liquid chromatograph, an ionization interface (or ionization source), a mass analyzer, and a detector, and In the current LC/MS, electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) are the two main ionization interfaces. In general, ESI is more sensitive, but its signal is easily affected by the sample matrix, and APCI is less affected by the sample matrix, but its device is more complicated and often has insufficient signal stability after long-term operation. In the actual detection, it is necessary to select the appropriate ionization interface for the matrix effect of the sample and the structural characteristics of the analyte, so that it is often inconvenient to replace the free interface for analysis. In order to reduce the replacement of ESI and APCI interfaces, commercial dual ionization interfaces (ESI and APCI) have recently appeared, but whether it is a separate APCI ionization interface or an APCI mode in a dual ionization interface, A metal needle is applied with a high voltage to initiate a corona discharge at the tip of the metal needle. When gaseous analyte molecules and gaseous solvent molecules ejected from the atomizer pass through the tip of the metal needle, a series of ions can be performed. An ion-molecule reaction produces analyte ions, which in turn can be followed by mass spectrometry.

However, the design of the previously introduced APCI interface allows the metal needle tip to be in direct contact with the liquid chromatographic exudate containing the sample matrix for a long time during the entire analysis, making it easy for solid particles to accumulate at the tip of the metal needle, resulting in unstable corona discharge. Even interrupted, which in turn affects the ionization efficiency of the gaseous analyte molecules, and in order to maintain the ionization efficiency, the sharpened metal needle end must be polished frequently, resulting in insufficient ease of use of the APCI interface and easily affecting the stability of subsequent analysis.

In view of the above, the main object of the present invention is to provide a free device which can avoid the direct contact of the liquid chromatography with the metal needle, thereby avoiding the influence of the sample matrix in the liquid chromatography on the tip of the metal needle. Corona discharge, which in turn improves the stability of ionization.

To achieve the above object, a free device provided by the present invention is applicable to a mass spectrometry system for ionizing a gaseous analyte molecule into an analyte ion. The free device mainly includes a sleeve and a metal needle capable of generating a corona discharge, the sleeve having an outlet end, and an air flow path communicating with the outlet end for supplying a reactive gas, and the metal needle Having a tip adjacent the outlet end of the sleeve and located in the gas flow path, the reactive gas can flow through the tip to dissociate into a plasma colliding with the gaseous analyte molecules to ionize the gaseous analyte molecules. Since the free device of the present invention utilizes a cannula to isolate a liquid chromatographic exudate containing a sample matrix and a solvent molecule from direct contact with the metal needle, the corona discharge of the metal needle tip can be stabilized, thereby improving the present invention. Ionization efficiency and stability of the free device.

In the free device provided by the present invention, the sleeve is preferably a high temperature resistant insulating material, and is preferably plastic, glass or ceramic. The material of the metal needle is preferably platinum (Pt), iridium (Ir), gold (Au), osmium (Os), palladium (Pd), yttrium (Re), yttrium (Rh), yttrium (Ru), the foregoing Metal alloy or stainless steel.

In the free device of the present invention, the tip of the metal needle is preferably coaxial with the outlet end of the sleeve.

In the free apparatus provided by the present invention, the reaction gas is preferably air, nitrogen (N ₂ ), helium (He), helium (neon, Ne), argon (argon, Ar) or Combination of the foregoing.

Another object of the present invention is to provide a mass spectrometry system using the above-described free device, which can directly analyze volatile samples in addition to improving analysis sensitivity and signal stability.

In order to achieve the above object, a mass spectrometry system provided by the present invention mainly comprises a mass analyzer, an atomizing device and the aforementioned free device. The mass analyzer has an inlet; the atomizing device has a nozzle for ejecting a nebulizer gas, a capillary penetrating and protruding from the nozzle, and a ring heating outside the nozzle A probe heater for heating a desolvation gas and ejecting the heated desolvent gas. Thereby, the analyte solution or protic solvent ejected from the capillary can be atomized more quickly into a gaseous analyte molecule or a gaseous solvent molecule.

In the mass spectrometry system provided by the present invention, the outlet end of the sleeve of the free device, the inlet of the mass analyzer, and the nozzle of the atomizing device are preferably adjusted to a preferred relative position for gas analysis The object molecule can fully perform the ionization reaction and the free analyte ion can quickly enter the mass analyzer, thereby reducing the loss of the analyte ion and improving the analysis sensitivity. Preferably, the outlet end of the sleeve is directed toward the inlet of the mass analyzer.

The mass spectrometry system provided by the present invention may further comprise a sample container for accommodating a sample capable of generating a volatile analyte. The air flow path of the sleeve communicates with the outlet end of the sleeve and the sample container. The proton solvent ejected from the capillary of the atomizing device is atomized by the atomizing gas and the desolvating gas into a gaseous solvent molecule, and then moves along a first path, and the reactive gas can carry the volatile analyte into the The airflow path is ejected from the outlet end through the tip of the metal needle to move along a second path that intersects the first path. Thereby, the mass spectrometry system of the present invention can directly place a sample having a volatile component into the sample container for immediate analysis.

With regard to the detailed configuration of the free device and the mass spectrometry system provided by the present invention and the features thereof, the embodiments will be exemplified and the drawings will be within the scope of the embodiments of the present invention which can be easily implemented by those skilled in the art. Be explained.

The following is a brief description of the contents of the drawings used in conjunction with the embodiments of the present invention, wherein: the first figure is a perspective view showing a free device according to a preferred embodiment of the present invention; and the second figure is a schematic view showing the present invention. In the mass spectrometry system, the relative positions of the free device, the mass analyzer and the atomizing device; the third figure is a schematic diagram showing that the analyte solution/proton solvent is atomized by the atomizing gas and the solvent to be a gaseous analyte molecule/ The state of the gaseous solvent molecule; the fourth figure is a schematic diagram showing the state of the mass spectrometry system of the second figure; the fifth figure is a schematic diagram showing the mass spectrometry system of the second figure used in conjunction with the sample container The sixth figure is a schematic view showing the aspect of the mass spectrometry system of the fifth figure when it is analyzed; the seventh figure A to F is the mass spectrum obtained by the experimental example 1 of the present invention; the eighth figure A to B is the present The relationship between the peak area of the signal obtained in Experimental Example 2 and the sample concentration; and the ninth diagrams A to D are the relationship between the peak area of the signal obtained in Experimental Example 3 and the flow velocity of the liquid chromatography. 10A to B are diagrams showing the relationship between the peak area of the signal obtained in Experimental Example 4 and the detection time; and FIGS. 11A to C are mass chromatograms obtained in Experimental Example 5 of the present invention; C is the mass chromatogram obtained in Experimental Example 6 of the present invention; the thirteenth graph A to B is the mass spectrum obtained in Experimental Example 7 of the present invention; and the fourteenth graphs A to B are the total mass obtained in Experimental Example 7 of the present invention. Ion chromatogram.

The Applicant first describes here that in the embodiments to be described below, the same reference numerals denote the same or similar elements.

Referring to the first figure, a free device 10 according to a preferred embodiment of the present invention mainly includes a sleeve 11 and a metal needle 13.

The sleeve 11 is generally cylindrical in this embodiment, but is not limited thereto in actual manufacture. The material of the sleeve 11 is preferably a high temperature resistant insulating material, and is preferably plastic, glass or ceramic. In this example, the sleeve 11 is made of polypropylene (PP). Next, the sleeve 11 has an outlet end 111 and an air flow path 113 communicating with the outlet end 111. In practical applications, as shown in the second figure, the air flow path 113 is for a reactive gas 20 to pass.

The reaction gas 20 is preferably air, nitrogen (N ₂ ), helium (He), neon (neon), argon (Ar) or a combination thereof. In this example, nitrogen (N ₂ ) was used.

The metal needle 13 is preferably made of an inert metal material, and preferably platinum (Pt), iridium (Ir), gold (Au), osmium (Os), palladium (Pd), yttrium (Re), yttrium (Rh). , ruthenium (Ru), alloy of the foregoing metals or stainless steel. In this example, stainless steel is used. Second, the metal needle 13 has a tip end 131. In this example, as shown in the second figure, the metal needle 13 is disposed at a position adjacent to the sleeve outlet end 111 and located on the air flow path 113 with its tip end 131 coaxial with the sleeve outlet end 111. .

In practical application, as shown in the second figure, the metal pin 13 can be electrically connected to a power supply P, thereby applying a high voltage to the metal pin 13 to initiate a corona discharge. The reaction gas 20 passing through the metal needle tip 131 is dissociated into a plasma 22 (as shown in the fourth figure) and ejected from the sleeve outlet end 111, and can collide with the gaseous analyte molecule 32 to ionize it into an analyte. Ion 34 is followed by subsequent analysis.

Since the free device 10 of the present invention is ionized by the plasma 22, the gaseous analyte molecules 32 can be ionized without directly contacting the metal needle 13, thereby preventing the residual deposition of the sample matrix in the gaseous analyte molecules 32. The metal needle tip 131 enables the metal needle 13 to be stably corona-discharged, thereby maintaining ionization efficiency and stability.

Next, referring to the second figure, the mass spectrometry system 40 provided by the present invention mainly includes a mass analyzer 50, an atomizing device 60, and the free device 10. Since the free device 10 is the same as the one described above, the applicant will not repeat it.

The mass analyzer 50, as shown in the second and fourth figures, has an inlet 51 for receiving the analyte ions 34 generated by ionization of the gaseous analyte molecules 32, and then The mass-to-charge ratio (m/z) is screened to generate a corresponding signal, and then the signals are converted into a mass spectrogram by a detector (not shown). The mass analyzer 50 can be a quadrupole mass analyzer, an ion trap mass analyzer, a time-of-flight mass analyzer (TOF), a magnetic field type. A magnetic field mass analyzer or a Fourier transform ion cyclotron resonance mass analyzer (FT-ICR). In this example, the mass analyzer 50 is a triple quadrupole mass analyzer.

The atomizing device 60 has, in this example, a nozzle 61, a capillary 63 that is disposed in the head 61 and partially protrudes from the head 61, and a heater that is disposed outside the head 61. 65. The capillary 63 is made of a metal material.

When assembled, the relative position and distance of the mass analyzer 50, the atomizing device 60, and the free device 10 are not particularly limited as long as the gaseous analyte molecules 32 can be ejected from the capillary 63 and atomized. The plasma 22 ejected from the cannula outlet end 111 of the free device 10 collides, thereby generating analyte ions 34, and the analyte ions 34 can move toward the mass analyzer 50 and enter the mass analyzer from the inlet 51. 50 for subsequent mass spectrometry analysis.

Preferably, the outlet end 111 of the sleeve 11 of the free device 10 is directed toward the inlet 51 of the mass analyzer 50; more preferably, the sleeve 11 of the free device 10 is coaxial with the mass analyzer 50. The inlet port 51 is configured to enable the ionized analyte ions 34 to be rapidly blown into the mass analyzer 50 by being blown by the reaction gas 20 which is not partially dissociated into a plasma, thereby reducing the loss of the analyte ions 34 and thereby improving the mass spectrum. The analytical sensitivity of the analysis system 40 is analyzed.

In the actual analysis, as shown in the third figure, an analyte solution 30 separated by a liquid chromatograph (not shown) can be ejected from the capillary 63, and an atomizing gas 70 is taken from the nozzle 61. Ejected to atomize the analyte solution 30 into gaseous analyte molecules 32, while a heated solvent desorbing gas 71 is ejected from the heater 65 to cause solvent in the analyte solution 30 ejected from the showerhead 61. The analyte solution 30 can be accelerated to become a gaseous analyte molecule 32. Thereafter, as shown in the fourth figure, the gaseous analyte molecule 32 collides with the plasma 22 to perform an ion-molecular reaction to generate analyte ions 34, which are again subjected to mass analyzer inlet 51 vacuum. The reaction and the reaction gas 20 are blown and enter the mass analyzer 50 for mass spectrometry.

Preferably, the atomizing gas 70 and the desolvating gas 71 are selected from the group consisting of air, nitrogen (N ₂ ), helium (He), helium (neon), argon (Ar) or the foregoing. The combination. In this example, nitrogen (N ₂ ) was used.

Since the ionization efficiency of the free device 10 of the present invention is excellent and stable, the mass spectrometry system 40 of the present invention has the advantages of high sensitivity and high signal stability.

Next, please refer to a fifth diagram, which is a mass spectrometry system 40' according to another embodiment of the present invention, which mainly includes the mass analyzer 50, the atomizing device 60, the free device 10, and a sample container 80. Since the free device 10, the mass analyzer 50, and the atomizing device 60 are the same as those described above, the applicant will not repeat them.

In this example, the sample container 80 can be a commercially available glass sample vial for receiving a sample S having a volatile component.

When assembled, the relative positions of the mass analyzer 50, the atomizing device 60, and the free device 10 are as described above, and the air flow path 113 of the free device 10 communicates with the outlet end 111 and transmits (but is not limited to A gas hose is connected to the sample container 80.

In the actual detection, as shown in the sixth figure, similar to the mechanism described in the third figure, a protic solvent system can be ejected from the capillary 63, and the atomizing gas 70 and the desolvating gas can atomize the proton solvent into a gaseous state. The solvent molecules move along a first path P1. On the other hand, the volatile analyte produced by the sample S is carried by the reactive gas 20 and enters the gas flow path 113. When the volatile analyte and the reactive gas 20 pass through the metal needle tip 131, the reaction The gas 20 is dissociated into a plasma and ejected from the outlet end 111 with the volatile analyte and moved along a second path P2 that intersects the first path P1. Thus, the gaseous solvent molecules, the plasma, and the volatile analyte collide with each other and undergo a series of ion-molecule reactions to produce analyte ions 34, which are subjected to a portion of the reaction gas that is not dissociated into a plasma. 20 is blown from the inlet 51 into the mass analyzer 50 for subsequent mass spectrometry analysis.

Thereby, the mass spectrometry system 40' of the present embodiment can perform on-the-spot analysis on the volatile components possessed by the sample.

It is worth mentioning that, as shown in the sixth figure, a gas source (not shown) for providing the reaction gas 20 can be connected to the sleeve 11 of the free device 10 by using a four-way switching valve V. The reaction gas 20 is directly controlled to enter the gas flow path 113 by rotating the four-way switching valve V, or is first passed through the inside of the sample container 80 to enter the gas flow path 113.

On the other hand, if the reaction gas 20 is nitrogen gas, it can be directly branched from a liquid nitrogen cylinder equipped with a general mass spectrometry system. In addition, the power supply P used in the present invention can also be equipped with a general-purpose mass spectrometry system, that is, a DC high-voltage power supply, and no other high-voltage power supply is required to simplify the device.

The present invention will be further clarified by the following experimental examples, which are only to better understand the present invention, and are not intended to limit the scope of the present invention, and those who have ordinary knowledge in the technical field do not violate the inventive spirit of the present invention. Various changes and modifications hereinafter are within the scope of the invention.

Applicants specifically stated here that the following experimental examples were performed using a mass spectrometer (model ACQUITY TQ Detector, available from Waters) with an ESI/APCI dual ionization interface (ESCi interface), which can be selected from the ESCi interface and / or APCI ionization mode, "ESCi" as referred to in the following examples of the invention refers to an APCI ionization mode using an ESCi free source. In addition, the mass spectrometer is equipped with a mass analyzer (three-stage quadrupole mass analyzer). The metal needle tip of the mass spectrometer belonging to the APCI ionization interface is placed in a plastic sleeve, and the metal needle is electrically connected to the DC high voltage power supply provided in the mass spectrometer, and The mass spectrometer is equipped with a liquid nitrogen cylinder to provide a reaction gas for generating plasma, and the free apparatus of the present invention can be obtained. Further, the ESI ionization interface in the mass spectrometer is used as the atomization device of the present invention.

Performance test of free device

<Experimental Example 1>

The ionization properties of the free apparatus of the present invention were tested by ionizing the six analytes shown in Table 1 using the free apparatus of the present invention. The name, structural formula, molecular weight of the waiting analyte and the number of the obtained mass spectrum are listed in Table 1 below.

【Table 1】

The six analytes shown in Table 1 were each dissolved in methanol (methanol, purity higher than 99.9%, HPLC grade, available from Mallinckrodt Chemicals) to prepare a stock solution having a concentration of 1 mg/mL. Thereafter, each stock solution was diluted with a 50% (v/v) aqueous methanol solution to a sample solution having a concentration of 1 μg/mL, and was directly injected.

1. Common detection parameter settings:

Sample solution injection flow rate: 20 μL / min;

Reaction gas flow rate: 300 mL / min;

Heater temperature: 80 ° C;

Atomizing gas flow rate: 400 L / hr;

Corona current: 0.5 μA for positive ion mode and 10 μA for negative ion mode.

2. The respective detection parameter settings are shown in Table 2 below.

【Table 2】

<Experimental Example 2>

The bisoprolol and p-cresol shown in Table 1 were separately dissolved in methanol (methanol, purity higher than 99.9%, HPLC grade, purchased from Mallinckrodt Chemicals) to prepare a concentration of 1 mg. /mL stock solution. Thereafter, each stock solution was diluted with 50% (v/v) aqueous methanol solution to a concentration of 2 ng/mL, 4 ng/mL, 8 ng/mL, 16 ng/mL, 32 ng/mL, 64 ng/mL. Samples were prepared at 125 ng/mL, 250 ng/mL, and 500 ng/mL.

1. Common detection parameter settings:

Liquid chromatography mobile phase flow rate: 0.5 mL / min;

Detection mode: multiple reaction monitoring (MRM detection);

Reaction gas flow rate: 300 mL / min;

Heater temperature: 80 ° C;

Atomizing gas flow rate: 400 L / hr;

Corona current: 0.5 μA for positive ion mode and 10 μA for negative ion mode.

2. The respective detection parameter settings are shown in Table 3 below.

【table 3】

<Experimental Example 3>

The stock solutions of the six test substances in Table 1 were prepared in substantially the same manner as in Experimental Example 1, and were diluted into a sample solution for detection.

1. Common detection parameter settings:

Liquid chromatography mobile phase flow rate: 0.1 mL / min, 0.3 mL / min, 0.5 mL / min and 1 mL / min;

Detection mode: multiple reaction monitoring (MRM detection);

Reaction gas flow rate: 300 mL / min;

Heater temperature: 80 ° C;

Atomizing gas flow rate: 400 L / hr;

Corona current: The free device of the present invention has a positive ion mode of 0.5 μA, a negative ion mode of 10 μA, an ESCi positive ion mode of 0.5 μA, and a negative ion mode of 10 μA.

2. Individual detection parameter settings:

The free apparatus of the present invention is shown in Table 3 above; ESCi is shown in Table 4 below.

【Table 4】

Free device performance test results

Figures 7 to 7 F show bisoprolol, pioglitazone, vanillin, ethyl vanillin, bisphenol A, respectively. And a mass spectrum obtained by detecting p-cresol by the mass spectrometry system of the present invention. It can be seen from the seventh figure A to the seventh figure F that the present invention can clearly detect the ion signal of the analyte ([M+H] ⁺ or [MH] regardless of the positive ion mode detection or the negative ion mode detection. ^- ), therefore the free device of the invention does have good ionization properties.

The graphs shown in Fig. A to B are graphs showing the relationship between the peak area of the signal obtained by detecting bisoprolol in the positive ion mode and the detection of pigliotone in the negative ion mode, respectively. The standard curve R ² values calculated from the eighth graphs A to B are all greater than 0.995, so that the free device of the present invention can be proved to have a good linear behavior.

The ninth diagrams A to B are diagrams showing the relationship between the signal peak area and the moving phase flow rate (mL/min) detected by the free device of the present invention in the positive and negative ion modes, and the ninth panel C to D is the ESCi dual ionization interface. The relationship between the signal peak area and the moving phase flow rate obtained by the positive and negative ion APCI mode detection.

It is clear from ninth to ninth figure D that the optimum mobile phase flow rate of the ESCi interface and the free device of the present invention is approximately in the range of about 0.4 to 0.6 mL/min. In this experiment, at a flow rate of 0.5 mL/min, the free device of the present invention still exhibited a higher signal than the ESCi double ionization interface.

Stability test

<Experimental Example 4>

The bisoprolol, pioglitazone, vanillin and ethyl vanillin in Table 1 above were separately dissolved in methanol (methanol, purity higher than 99.9%, HPLC grade, It was purchased from Mallinckrodt Chemicals) and formulated into a stock solution at a concentration of 1 mg/mL. Thereafter, each stock solution was mixed with blank urine to prepare an added urine sample containing bisoprolol and pirimines at a concentration of 500 ng/mL. Pioglitazone), vanillin and ethyl vanillin. Thereafter, the added urine sample was diluted 100-fold with 50% (v/v) aqueous methanol solution and detected in positive ion mode, and diluted 2 times and detected in negative ion mode. The test was carried out by continuously quantitatively injecting the diluted working solution (injection) 30 times in 3.5 hours.

The mobile phase used in the assay was a 50% (v/v) aqueous methanol solution consisting of methanol (purity above 99.9%, HPLC grade, purchased from Mallinckrodt Chemicals) and water (secondary ultrapure water (18.2 MΩ)). Mixed preparation.

Bisoprolol and pioglitazone were tested for positive ion mode; vanillin and ethyl vanillin were tested for negative ion mode.

1. Common detection parameter settings:

Liquid chromatography mobile phase flow rate: 0.2 mL / min;

Detection mode: multiple reaction monitoring (MRM detection);

Injection method: positive ion mode using flow injection analysis (FIA); negative ion mode using liquid chromatography column (C18, size 4.6 × 50 mm, 5 μm, model MOS2, purchased from Hypersil);

Reaction gas flow rate: >500 mL/min;

Heater temperature: 80 ° C;

Atomizing gas flow rate: 400 L / hr;

Corona current: The free device of the present invention has a positive ion mode of 2.0 μA, a negative ion mode of 10 μA, an ESCi positive ion mode of 2.0 μA, and a negative ion mode of 10 μA.

2. The respective detection parameter settings are shown in Table 5 below.

【table 5】

Stability test result

The tenth graphs A to B are graphs showing the relationship between the peak area of the analyte signal and the detection time obtained by continuously injecting 30 times in 3.5 hours using the free device of the present invention and the ESCi double ionization interface.

From the results obtained in the tenth graphs A to B, the coefficient of variance (CV) of each signal peak area was calculated, and the results are shown in Table 6 below. The relative variability of the analyte obtained using the free device of the present invention is significantly lower than that obtained using the ESCi double ionization interface, so that the stability of the free device of the present invention is significantly higher.

[Table 6]

Sensitivity test

<Experimental Example 5>

The sensitivity of the free apparatus and mass spectrometry system of the present invention was tested by the mass spectrometry system of the present invention by detecting the six plasticizers (phthalate) shown in Table 7 below. The names and structural formulas of these plasticizers are listed in Table 7 below.

[Table 7]

DBP, BBP, DEHP, DNOP, DINP, and DIDP in Table 7 were dissolved in methanol (methanol, purity higher than 99.9%, HPLC grade, available from Mallinckrodt Chemicals) to prepare a stock solution at a concentration of 1 μg/mL ( Stock solution). Thereafter, each stock solution was diluted with methanol to form a working solution containing DBP, BBP, DEHP, DNOP, DINP, and DIDP at a concentration of 250 ng/mL. Thereafter, the working solution was detected in a positive ion mode.

The mobile phase used in the assay was prepared by mixing methanol with 5 mM ammonium acetate in a ratio of 9:1 (v/v).

1. Common detection parameter settings:

Liquid chromatography mobile phase flow rate: 0.4 mL / min;

Detection mode: multiple reaction monitoring (MRM detection);

Reaction gas flow rate: 300 mL / min;

Heater temperature: 100 ° C;

Atomizing gas temperature: 400 ° C;

Atomizing gas flow rate: 650 L / hr;

Corona current: The free ion mode of the free device of the present invention is 0.75 μA, the ESCi positive ion mode is 1.56 μA, and the APCI positive ion mode is 1.62 μA.

2. The setting of each detection parameter is shown in Table 8.

[Table 8]

<Experimental Example 6>

The sensitivity of the free device of the present invention and the mass spectrometry system in the negative ion mode was tested using the mass spectrometry system of the present invention to detect the three analytes shown in Table 9 below. The names and structural formulas of the waiting samples are listed in Table 9 below.

[Table 9]

The test substances in Table 9 were separately dissolved in water (secondary ultrapure water (18.2 MΩ)) to prepare a stock solution having a concentration of 1 mg/mL. Thereafter, each stock solution was mixed with blank urine to prepare an added urine sample containing BMA, p-cresol and o-cresol in a concentration of 200 ng/mL. . After appropriate sample pretreatment, the free device, ESCi and APCI interfaces of the present invention were tested in negative ion mode.

The mobile phase used in the assay was a 40% (v/v) aqueous acetonitrile solution consisting of acetonitrile (purity higher than 99%, HPLC grade, purchased from JT Baker) and water (secondary ultrapure water (18.2 MΩ)). Mixed preparation.

1. Common detection parameter settings:

Liquid chromatography mobile phase flow rate: 0.15 mL / min;

Liquid chromatography column: Diphenyl column, size 2.1 × 30 mm, 3.5 μm, purchased from Supelco, and C18 column, size 2.1 × 150 mm, 2.6 μm, purchased from Phenomenex;

Detection mode: multiple reaction monitoring (MRM detection);

Reaction gas flow rate: >500 mL/min;

Heater temperature: 80 ° C;

Atomizing gas temperature: 400 ° C;

Atomizing gas flow rate: 500 L / hr;

Corona current: the negative ion mode of the free device of the present invention is 10 μA, the ESCi negative ion mode is 10 μA, and the APCI negative ion mode is 10 μA;

Mass Analyzer Voltage: The free device of the present invention is 50 V, the ESCi is 50 V, and the APCI is 50 V.

2. The individual detection parameters are set as shown in Table 10.

[Table 10]

Sensitivity test result

11th to Ath are mass chromatograms of six plasticizers obtained by using the free device of the present invention, the ESCi double ionization interface, and the APCI ionization dedicated interface detection, respectively, wherein the tenth Both Figures B and C are normalized in Figure 11A.

Twelfth Figures A to C are mass chromatograms of BMA, p-cresol and o-cresol obtained by using the free device of the present invention, the ESCi double ionization interface and the APCI ionization dedicated interface detection, respectively. ), wherein the twelfth graphs B and C are all normalized in the twelfth graph A.

It can be clearly seen from the eleventh drawing A to C and the twelfth drawing A to C that, in the free device of the present invention, in addition to the six plasticizers (as shown in FIG. 11A) and the BMA can be clearly measured. In addition to the signals of p-cresol and o-cresol (as shown in Figure 12A), the signal intensity is also significantly higher than that of the traditional APCI ionization interface, and it is also more commercial than the ESCi diion. The signal intensity of the interface is about 2 times higher. Therefore, the mass spectrometry system using the free device of the present invention does have better analytical sensitivity.

Direct analysis of volatile components of samples

<Experimental Example 7>

Direct analysis of the volatile components of the sample was carried out using the mass spectrometry system 40' shown in Fig. 6 of the present specification.

In this example, an ice cream (containing volatile component sample S) is placed in the sample container 80, and then the reaction gas 20 is passed into the sample container 80 to carry the volatile analyte of the ice cream into the gas flow path 113. The analysis was carried out after ionization of the free device 10 of the present invention.

The reaction gas used in the analysis was nitrogen (0.99999, purchased from Wansheng Gas). The protic solvent used was a 50% (v/v) aqueous methanol solution prepared by mixing methanol (purity higher than 99%, HPLC grade, available from Mallinckrodt Chemicals) and water (secondary ultrapure water (18.2 MΩ)). Made.

Detection parameter setting:

Liquid chromatography mobile phase flow rate: 0.1 mL / min;

Reaction gas flow rate: >500 mL/min;

Heater temperature: 80 ° C;

Atomizing gas temperature: 400 ° C;

Atomizing gas flow rate: 400 L / hr;

Corona current: 2.0 μA in negative ion mode;

Mass analyzer voltage: 15 V.

Volatile sample test results

Thirteenth Figures A to B are mass spectra obtained by directly detecting solid powders of vanillin and ethyl vanillin in positive and negative ion modes using the mass spectrometry system of the present invention, respectively, and Figure 14A To B are the total ion chromatograms obtained by analyzing the two different brands of ice cream in the positive and negative ion modes in the multiple reaction monitoring mode.

From Figures 14A and B, it can be seen that when the four-way switching valve V is controlled to cause the reaction gas 20 to never pass through the sample container 80 to pass through the sample container 80, the mass total ion chromatogram appears as a continuous mass spectrometry signal, As shown in Figures 13A and B and Figures 14A and B, in the negative ion mode, the mass spectrometry system of the present invention can measure volatile vanillin mass spectrometry signals from two different ice cream samples. Among the A brand ice cream samples (Fig. 14A), the vanilla aldehyde (ethyl vanillin)-based signal was measured, while in the B brand ice cream sample, the vanillin-based signal was measured. Figure 14 B). From this it can be demonstrated that the mass spectrometry system of the present invention does have the ability to directly analyze the volatile components contained in the sample.

In summary, since the free device of the present invention can prevent the liquid chromatography to directly contact the metal needle, it has excellent stability. Secondly, the mass spectrometry system using the free device of the present invention also exhibits better analytical sensitivity than the mass spectrometry system using the conventional APCI and ESCi dual ionization interface. Furthermore, the mass spectrometry system of the present invention is also capable of directly analyzing samples having volatile components, and thus has excellent application potential in fields such as food, spices, agricultural products or medicine.

10‧‧‧Free device

11‧‧‧ casing

111‧‧‧export end

113‧‧‧ airflow path

13‧‧‧Metal Needle

131‧‧‧ tip

20‧‧‧Reactive gas

22‧‧‧ Plasma

30‧‧‧ Analyte solution

32‧‧‧Gaseous analyte molecules

34‧‧‧ Analyte ions

40,40’‧‧‧Mass Spectrometry System

50‧‧‧Quality Analyzer

51‧‧‧Inlet

60‧‧‧Atomizing device

61‧‧‧ sprinkler

63‧‧‧ Capillary

65‧‧‧heater

70‧‧‧ atomizing gas

71‧‧‧ Desolvent gas

80‧‧‧ sample container

P‧‧‧Power supply

P1‧‧‧First path

P2‧‧‧ second path

S‧‧‧ sample

V‧‧‧ four-way switching valve

The first figure is a perspective view showing a free device according to a preferred embodiment of the present invention;

The second figure is a schematic diagram showing the relative positions of the free device, the mass analyzer and the atomizing device in the mass spectrometry system of the present invention;

The third figure is a schematic diagram showing the state in which the analyte solution/proton solvent is atomized into the gaseous analyte molecule/gaseous solvent molecule through the atomizing gas and the solvent removal gas;

The fourth figure is a schematic diagram showing the aspect of the mass spectrometry system of the second figure for analysis;

The fifth figure is a schematic diagram showing the aspect of the mass spectrometry system of the second figure used in combination with the sample container;

The sixth figure is a schematic diagram showing the aspect of the mass spectrometry system of the fifth figure when it is analyzed;

7A to F are mass spectra obtained in Experimental Example 1 of the present invention;

8A to B are diagrams showing the relationship between the signal peak area and the sample concentration obtained in Experimental Example 2 of the present invention;

The ninth diagrams A to D are diagrams showing the relationship between the peak area of the signal obtained in Experimental Example 3 of the present invention and the flow velocity of the liquid chromatography;

10A to B are diagrams showing the relationship between the signal peak area and the detection time obtained in Experimental Example 4 of the present invention;

11A to C are mass chromatograms obtained in Experimental Example 5 of the present invention;

Twelfth Figures A to C are mass chromatograms obtained in Experimental Example 6 of the present invention;

Thirteenth Figures A to B are mass spectra obtained in Experimental Example 7 of the present invention;

Fourteenth A to B are the mass total ion chromatograms obtained in Experimental Example 7 of the present invention.

10. . . Free device

11. . . casing

111. . . Exit end

113. . . Airflow path

13. . . Metal needle

131. . . Cutting edge

Claims (7)

A free device comprising: a sleeve having an outlet end and an air flow path communicating with the outlet end, the air flow path for passing a reactive gas; and a metal needle capable of generating a corona discharge, a tip adjacent the outlet end of the sleeve and located in the gas flow path, the tip of the metal needle being coaxial with the outlet end of the sleeve, the reactive gas flowing through the tip to dissociate into a plasma and from the sleeve The outlet end is sprayed. The free device of claim 1, wherein the sleeve is made of an insulating material. The free device according to claim 1, wherein the metal needle is made of a metal selected from the group consisting of platinum, rhodium, gold, ruthenium, palladium, iridium, osmium, iridium, an alloy of the foregoing metals, and stainless steel. A mass spectrometry system comprising: a mass analyzer having an inlet; an atomizing device having a capillary tube for atomizing a analyte solution or proton solvent to atomize into a gaseous analyte molecule or The free device of any one of claims 1 to 3, wherein the outlet end of the sleeve is toward the inlet of the mass analyzer. The mass spectrometry system of claim 4, wherein the atomizing device further has a showerhead for ejecting an atomizing gas, and a heater surrounding the showerhead for ejecting a solvent-depleted gas, the capillary threading Set and protrude from the nozzle. The mass spectrometry system of claim 4, wherein the tubing of the free device is coaxial with the inlet of the mass analyzer. The mass spectrometry system of claim 4, further comprising a sample container for accommodating a sample capable of producing a volatile analyte, the gas flow path of the sleeve being connected to the outlet end and the sample container, The gaseous solvent molecules sprayed by the capillary can be moved along a first path, and the reaction gas system can carry the volatile analyte from the outlet end through the airflow path, and along the first and the first The second path where the paths intersect moves.