SPRAY IONIZATION DEVICE, ANALYSIS DEVICE, AND SURFACE COATING DEVICE

A spray ionization device comprising: a first pipe body that has a first flow path which allows a liquid to flow therethrough, and has, at one end thereof, a first outlet through which the liquid is sprayed out; a second pipe body that surrounds the first pipe body; and a third pipe body that surrounds the second pipe body with a space interposed therebetween, that has a second flow path allowing a gas to flow therethrough, and that has a second outlet at the one end. At least the leading end part of the third pipe body including the second outlet is made of an electrically conductive material so as to serve as an electrode. Charged droplets can be sprayed from the second outlet by applying an electric field to droplets sprayed from the first outlet using a power supply connected to the electrode.

BACKGROUND OF THE INVENTION

Technical Field

The present invention relates to a spray ionization device.

Background Art

A mass spectrometer can count ions constituting a substance by each mass-to-charge ratio to obtain ionic strength which is quantitative information on the substance. The mass spectrometer can perform more accurate analysis by obtaining ionic strength having a favorable signal-to-noise ratio. Therefore, an analysis target, which is an ionized or charged material, needs to be sufficiently introduced.

Examples of a method of ionizing a liquid sample include an electrospray ionization method. With the electrospray ionization method, high voltage of several kilovolts is applied to a sample solution in a narrow tube, a liquid cone (so-called Taylor cone) is formed at the tip of an outlet port, electrically charged droplets are ejected from the tip, solvents evaporate to reduce the volume of the electrically charged droplets, and the droplets finally split apart to generate gas-phase ions. This method can form electrically charged droplets at a rate of ejecting 1 to 10 μL/min of solution, in which the ejection rate is not sufficient for use in conjunction with a liquid chromatography method.

A gas spray assisted electrospray ionization method (see, for example, U.S. Pat. No. 8,809,777) may be an example of a method for supporting generation of electrically charged droplets and vaporization of solvents by ejecting a gas from an outer tube surrounding a narrow tube of a sample solution, in order to promote vaporization of electrically charged droplets.

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

However, the gas spray assisted electrospray ionization method as disclosed in U.S. Pat. No. 8,809,777 generates electrically charged droplets having a large particle size; therefore, there is a need to use techniques such as promoting vaporization of solvents by using a heated gas, atomizing electrically charged droplets by collision with a plate-shaped target, or making the ejection direction orthogonal to the direction of introducing the atomized and electrically charged droplets in order to remove excessively large electrically charged droplets; as a result, electrically charged droplets cannot be efficiently obtained, which has been a problem.

One object of the present invention is to solve the aforementioned problems and provide a spray ionization device which can obtain atomized and electrically charged droplets, and is capable of efficiently ionizing molecules, clusters, etc. contained in liquid.

Means for Solving the Problems

One aspect of the present invention provides a spray ionization device including:

a first tube including a first channel through which a liquid can flow, the first tube including a first outlet for ejecting the liquid at one end; a second tube surrounding the first tube; and a third tube surrounding the second tube with a gap, and having a second channel through which gas can flow, the third tube having a second outlet at the one end, in which the second channel is defined by an outer circumferential surface of the second tube and an inner circumferential surface of the third tube, in which the second outlet of the third tube is disposed at the same position in an axial direction as the first outlet or more downstream than the first outlet, an opening diameter of the second outlet is formed to be smaller than a diameter of the outer circumferential surface of the second tube, and the third tube has at least a tip including a second outlet consisting of an electrically conductive material as an electrode, and capable of applying an electric field to droplets ejected from the first outlet by a power source connected to the electrode to eject electrically charged droplets from the second outlet.

The second outlet of the third tube having the second channel through which gas can flow is arranged at the same position in the axial direction as the first outlet of the first tube having the first channel through which liquid can flow, or more downstream than this, and the opening diameter of the above-mentioned second outlet is formed to be smaller than the diameter of the outer circumferential surface of the above-mentioned second tube; therefore, in the region between the first outlet and the second outlet, the liquid ejected from the first outlet is atomized by the gas flowing in along the inner circumferential surface of the third tube from upstream thereof, and further, the atomized droplets are electrically charged by the electric field from the tip of the third tube. Since the electrically charged droplets are atomized, desolvation by evaporation is easily conducted, and thus it is possible to provide a spray ionization device capable of efficiently ionizing molecules, clusters, etc. of components contained in the sample liquid Lf.

PREFERRED MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that elements that are common between a plurality of drawings are denoted by the same reference characters, and detailed descriptions of such elements will not be repeated.

First Embodiment

FIG.1is a diagram schematically illustrating a configuration of a spray ionization device according to a first embodiment of the present invention.FIGS.2A and2Bare cross-sectional views of a nozzle of a sprayer, in whichFIG.2Ais an enlarged cross-sectional view of the nozzle inFIG.1, andFIG.2Bis a cross-sectional view along arrows Y-Y inFIG.2A.

Referring toFIGS.1,2A and2B, a spray ionization device10according to a first embodiment of the present invention includes: a sprayer11; a container12containing a sample liquid Lf to be supplied to the sprayer11; a cylinder13for containing a spraying gas Gf to be supplied to the sprayer11; and a high-voltage power source14for applying a high electric field to droplets of the ejected sample liquid Lf. In the spray ionization device10, a nozzle15for ejecting electrically charged droplets is formed at one end (hereinafter also referred to as an ejection end) of the sprayer11. The sample liquid Lf and the spraying gas Gf are supplied from further toward the opposite end than the nozzle15(hereinafter also referred to as a supply end). The sample liquid Lf may be continuously or intermittently supplied from the container12by way of a pump17or the like. The sample liquid Lf may contain an analysis target in solvents, or may contain dissolved components, particulate matter, or the like, for example. The spraying gas Gf is supplied from the compressed gas cylinder13through the valve16to the supply port23s.Inert gas such as nitrogen gas or argon gas, or air can be used for the spraying gas Gf, for example. A heating unit19such as a heater or dryer for heating the spraying gas Gf may be provided between the compressed gas cylinder13or the valve16and the supply port23s.The spraying gas Gf is heated, whereby vaporization of solvents in the ejected sample liquid Lf can be promoted, and electrically charged droplets can be obtained more efficiently.

The sprayer11includes a liquid supply tube21, a protective tube22surrounding the liquid supply tube21, and a gas supply tube23that surrounds the protective tube22with a gap. The liquid supply tube21, protective tube22and the gas supply tube23have a triple tube structure, in which the tubes are preferably coaxial (central axis X-X) with one another.

The liquid supply tube21extends from the supply end to the ejection end. The liquid supply tube21includes a first channel24being tubular and defined by an inner circumferential surface21bof the liquid supply tube21, and includes an outlet21aof the nozzle15at the ejection end. In the liquid supply tube21, the sample liquid Lf is supplied from the supply side, passes through the first channel24and is ejected from the outlet21a.

A diameter (inner diameter) of the inner circumferential surface21bof the liquid supply tube21is preferably 10 μm to 250 μm, and a diameter (outer diameter) of an outer circumferential surface21cof the liquid supply tube21is preferably 100 μm to 400 μm. In terms of atomizing droplets, an opening diameter of the outlet21ais preferably 0.2 μm to 150 μm. In terms of atomizing droplets, the thickness (wall thickness) of the liquid supply tube21is preferably 1 μm to 50 μm. The liquid supply tube21is preferably formed from an electrically conductive material such as stainless steel (for example, SUS316), or a dielectric material made of glass and plastic.

The protective tube22surrounds the liquid supply tube21, and extends from the supply end to the ejection end. A tip22aon the ejection side is arranged more to the supply side than the outlet21aof the liquid supply tube21.

The gas supply tube23includes a second channel25defined by an inner circumferential surface23b,23b1of the gas supply tube23and the outer circumferential surface22cof the protective tube22, and includes an outlet23aof the nozzle15. Although not limited in particular, a diameter (inner diameter) of the inner circumferential surface23bof the gas supply tube23is, for example, 4 mm further toward the supply end than the nozzle15.

The spraying gas Gf is pressurized and supplied from the supply port23sof the gas supply tube23, flows through the second channel25, and is ejected from the outlet23a.A flow rate of the spraying gas Gf is appropriately set in accordance with the flow rate of the sample liquid Lf, and is set to 0.5 L/min to 5 L/min, for example.

At the outlet23a,the gas supply tube23functions as an electrode18for applying a high electric field to droplets of the sample liquid Lf ejected from the outlet21aof the liquid supply tube21. In the gas supply tube23, at least the tip including the outlet23ais formed from a conductive material, e.g. metallic material. As the metallic material, it is possible to use stainless steel (e.g., SUS316), aluminum or the like, and it is preferably stainless steel in the point of the heat-insulating property during heating. It should be noted that the entirety of the gas supply tube23may be formed by a conductive material such as a metal tube. A high-voltage power source14is connected to the electrode18. The high-voltage power source14is a power source for generating high-voltage direct current voltage, and is connected to the electrode18. The high-voltage power source14applies voltage of e.g., 3 kV to the electrode18, and preferably applies voltage in a range of −5 kV to +5 kV in terms of ionization.

In the nozzle15, the outlet23aof the gas supply tube23is arranged at the same position in the X-axis direction as the outlet21aof the liquid supply tube21, or further downstream therefrom. The gas supply tube23is formed such that a portion23b1of the inner circumferential surface of the gas supply tube23has a diameter that progressively decreases from upstream toward downstream, whereby the channel area of the second channel25progressively decreases towards downstream. Here, the channel area refers to an area occupied by the second channel25on a plane perpendicular to the central axis X, in which the area is surrounded by the inner circumferential surface23b1of the gas supply tube23and the outer circumferential surface21cof the liquid supply tube21as illustrated inFIG.2B. The distance (D3) in the X-axis direction between the outlet21aof the liquid supply tube21and the outlet23aof the gas supply tube23is preferably set to the range of 0 to 1 mm, in terms of the electrification of droplets.

An opening diameter D2of the outlet23aof the gas supply tube23is formed so as to become smaller than the diameter D1of the outer circumferential surface of the protective tube22. The flow velocity of the spraying gas Gf flowing through the gas supply tube23increases, whereby it is possible to promote atomization of droplets of the sample liquid Lf ejected from the outlet21aof the liquid supply tube21, and the atomized droplets can be electrically charged by the high electric field applied at the outlet21a.

The gas supply tube23is preferably formed such that the diameter D2of the inner circumferential surface of the outlet23aof the gas supply tube23is equal to or larger than the opening diameter of the outlet21aof the surface liquid supply tube21. With such a configuration, droplets of the sample liquid Lf are ejected from the outlet21aof the liquid supply tube21, enveloped in the spraying gas Gf flowing through the second channel25, and flow downstream (page right side) while focusing along the X-axis in the central direction. As a result, droplets of the sample liquid Lf are suppressed from contacting the inner circumferential surface22b1of the gas supply tube23in the vicinity of the outlet21aof the liquid supply tube21, whereby the nozzle15can be prevented from clogging. In addition, the flow of the ejected sample liquid Lf focuses by the spraying gas Gf, whereby droplets are atomized.

In the nozzle15, the constriction portion26of the second channel25may be formed by the tip22aof the protective tube22and the portion23b1of the inner circumferential surface of the gas supply tube23. As a result, the second channel25is formed such that the channel area of the second channel25progressively decreases from the supply end to the constriction portion26. The spraying gas Gf passes through the constriction portion26to gain the flow velocity, and the flow of droplets of the sample liquid Lf ejected from the outlet21aof the liquid supply tube21further focuses, promoting atomization of droplets. Droplets ejected from the outlet21aof the liquid supply tube21can be further suppressed from flowing backward and entering the constriction portion26. As a result, clogging of the constriction portion26due to precipitation of components such as salts contained in droplets can be suppressed, whereby stable ejection can be achieved. This constriction portion26achieves a flow-focusing effect, in which droplets ejected from the outlet21acan be ejected at a narrower angle (i.e., in a smaller lateral spreading range with respect to the ejection direction) than the case without the constriction portion26. As a result, efficiency of generating gas phase ions in the ejected and electrically charged droplets can be enhanced.

The outer circumferential face21cof the liquid supply tube21, has an outer diameter formed to be constant towards the outlet21a,whereby the flow of spraying gas Gf converges the ejected sample liquid Lf at the outlet21aof the liquid supply tube21, and it is possible to suppress splashing of the sample liquid Lf and effectively form droplets. It should be noted that the end face of the outlet21amay be formed so as to progressively decrease in diameter from the upstream side towards the outlet21a.

According to the first embodiment, the outlet23aof the gas supply tube23is arranged at the same position in the X-axis direction as the outlet21aof the liquid supply tube21or more downstream thereto, and the opening diameter D2of the outlet23aof the gas supply tube23is formed to be smaller than the diameter D1of the outer circumferential surface of the protective tube22; therefore, in a region between the outlet21aof the liquid supply tube21and the outlet23aof the gas supply tube23, the sample liquid Lf ejected from the outlet21aof the liquid supply tube21is atomized by the spraying gas Gf flowing in from the upstream along the inner circumferential surface23b1of the gas supply tube23, and further, the atomized droplets electrically charge by the electric field from the tip of the gas supply tube23. Since the electrically charged droplets are atomized, desolvation by evaporation is easily conducted, and thus it is possible to provide a spray ionization device capable of efficiently ionizing molecules, clusters, etc. of components contained in the sample liquid Lf.

FIGS.3A and3Bare cross-sectional views illustrating a variation of the nozzle of the sprayer of the first embodiment according to the present invention. Referring toFIG.3A, the nozzle35of the first variation includes a blocking member37along a circumferential direction in a gap between the outer circumferential surface21cof the liquid supply tube21and the inner circumferential surface22bof the protective tube22, at the tip22atoward the ejection end of the protective tube22. The blocking member37blocks this gap. Except that the closing member37is provided, the nozzle35has the same configuration as the nozzle15of the sprayer illustrated inFIGS.2A and2B. With this configuration, the blocking member37prevents the spraying gas Gf having passed through the gas between the tip22aof the protective tube22and the inner circumferential surface23b1of the gas supply tube23(or constriction portion26) from entering the gap between the outer circumferential surface21cof the liquid supply tube21and the inner circumferential surface22bof the protective tube22. As a result, turbulence of the spraying gas Gf by entering to the gap is suppressed from occurring, the flow of droplets of the sample liquid Lf focuses, and atomization and electrical charging of droplets are promoted.

Referring toFIG.3B, in the nozzle45of the second variation, a blocking member47is provided entirely along the circumferential direction and X-axis direction (longitudinal direction) of the gap between the outer circumferential surface21aof the liquid supply tube21and the inner circumferential surface22bof the protective tube22. In other words, the blocking member47is formed so that the protective tube22makes contact along the circumferential direction and longitudinal direction with the liquid supply tube21. It is thereby possible to fix the liquid supply tube21, and suppress the occurrence of turbulence from entry of spraying gas Gf to the gap. It should be noted that, by appropriately selecting the inside diameter of the protective tube22or outside diameter of the liquid supply tube21, it may be formed so that the inner circumferential surface22bof the protective tube22directly contacts the outer circumferential surface21cof the liquid supply tube21.

Second Embodiment

FIG.4is a diagram schematically illustrating a configuration of a spray ionization device according to a second embodiment of the present invention, andFIG.5is a cross-sectional view of a nozzle of a sprayer of this spray ionization device. Referring toFIGS.4and5, the spray ionization device110has a sprayer111with a quadruple-tube structure having a liquid supply tube21, a protective tube22surrounding the liquid supply tube21, a gas supply tube23surrounding the protective tube22with a gap, and a second gas supply tube128surrounding the gas supply tube23. The structures of the liquid supply tube21, protective tube22and gas supply tube23are similar to the sprayer11of the first embodiment.

In the sprayer111, the sheath gas Gf2is supplied to the supply opening128svia the valve116from a compressed gas cylinder113in the second gas supply tube128. The second gas supply tube128has a third channel129defined by an outer circumferential surface23cof the gas supply tube23and an inner circumferential surface128bof the second gas supply tube128, and extending in the X-axis direction. The inner circumferential surface128bof the second gas supply tube128is formed so as to have a constant diameter from the supply side toward downstream until the position128d.The position128dis a position opposing the position at which the outer circumferential surface23cof the gas supply tube23starts to decrease in diameter towards the outlet23a.Furthermore, in the second gas supply tube128, the inner circumferential surface128b1progressively expands in diameter from the position128dtowards the outlet128a.The sheath gas Gf2thereby flows through the third channel129, ejects at the position128d,flows in the direction of the outlet23aalong the outer circumferential surface23cof the gas supply tube23, and flows so as to focus the electrically charged and atomized droplets ejected from the outlet21aof the liquid supply tube21a.Further downstream therefrom, since the inner circumferential surface128b1of the second gas supply tube128progressively expands in diameter, the sheath gas Gf2flows so as to spread in the lateral direction to downstream. It is thereby possible to focus the flow of electrically charged and atomized droplets, and promote desolvation.

A heating unit119may be provided downstream of the valve116so as to supply the sheath gas Gf2as heated gas; or a heating unit such as a ring heater (not illustrated) may be provided downstream of the outlet23aof the gas supply tube23so as to surround a second gas supply tube128. As a result, desolvation of ejected droplets can be supported.

It should be noted that, in the second gas supply tube128, the inner circumferential surface128b1may have a constant diameter from the position128dtoward the outlet128a.

As a variation of the spray ionization device according to the second embodiment, the portion of the nozzle115consisting of the liquid supply tube21, protective tube22and gas supply tube23may be replaced with the nozzle35shown inFIG.3A, or the nozzle45shown inFIG.3B.

According to the second embodiment, the sheath gas Gf2passing through the third channel129of the second gas supply tube128flows so as to focus the electrically charged and atomized droplets ejected from the outlet21aof the liquid supply tube21, and further downstream therefrom, since the inner circumferential surface128b1of the second gas supply tube128progressively expands in diameter, the sheath gas Gf2flows so as to spread in the lateral direction to downstream. It is thereby possible to focus the flow of electrically charged and atomized droplets, and promote desolvation.

Hereinafter, measurement examples prepared using examples of the spray ionization devices according to embodiments of the present invention will be shown. Example 1 used a configuration having the sprayer11in the spray ionization device10of the first embodiment shown inFIGS.1,2A and2B. The gas supply tube23was formed from SUS316, the high-voltage power source of a mass spectrometer main body was connected to the gas supply tube23, and the gas supply tube23was used as the electrode. The inside diameter of the liquid supply tube21is 110 μm, and the opening diameter (D2) of the gas supply tube23is 200 μm. The outside diameter (D1) of the protective tube22is 1600 μm. The distance (D3) between the outlet21aof the liquid supply tube21and the outlet23aof the gas supply tube23was set as 0 mm.

Example 2 used a configuration having the sprayer111in the spray ionization device110of the second embodiment shown inFIGS.4and5.

The spray ionization device of Comparative Example 1 was an ESI ion source applying the gas spray assist electrospray ionization (ESI) method, and used a sprayer (ESI probe (ion source)) belonging to a mass spectrometer model LCMS-2020 manufactured by Shimadzu Corp. The spray ionization device of Comparative Example 2 was an ESI ion source adopting the same ESI method, and used a sprayer belonging to a mass spectrometer model LCMS-8060 manufactured by Shimadzu Corp.

FIG.6is a schematic cross-sectional view of the nozzle of the sprayer according to Comparative Example 1. Referring toFIG.6, the nozzle215of the sprayer of Comparative Example 1 has a double-tube structure, and has the liquid supply tube221through which the sample liquid Lf flows, and the gas supply tube223surrounding the liquid supply tube221and through which the spraying gas Gf flows. The outlet221aof the liquid supply tube221is provided further downstream from the outlet223aof the gas supply tube223. The liquid supply tube221and gas supply tube223are formed from a metallic material (SUS316). Using the gas supply tube223as the electrode218, the high-voltage power source14was connected thereto, and a high electric field was applied from the outlet223aof the gas supply tube223to electrically charge droplets of the sample liquid Lf ejected from the outlet221aof the gas supply tube221.

FIG.7is a schematic cross-sectional view of the nozzle of the sprayer according to Comparative Example 2. Referring toFIG.7, the nozzle315of the sprayer of Comparative Example 2 has a triple-tube structure, and includes the liquid supply tube221through which the sample liquid Lf flows, the gas supply tube223surrounding the liquid supply tube221and through which the spraying gas Gf flows, and the second gas supply tube328surrounding the gas supply tube223and through which heated sheath gas Gf2flows. The liquid supply tube221and gas supply tube223are formed similarly to Comparative Example 1. The second gas supply tube228is formed from a metallic material (SUS316). Using the gas supply tube223as the electrode, the high-voltage power source14was connected to this, and a high electric field was applied from the outlet223aof the gas supply tube223to electrically charge droplets of the sample liquid Lf ejected from the outlet221aof the gas supply tube221. The tip328aof the second gas supply tube328is arranged close to the position at which the outer circumferential surface23cof the gas supply tube23starts to decrease in diameter towards the outlet23a.

The spray ionization device of Example 1 was applied to the LC (liquid chromatography)/MS (mass spectrometry)/MS device, a model LC-10 series manufactured by Shimadzu Corp. was used as the LC device, and the model LCMS-2020 manufactured by Shimadzu Corp. was used as the MS device. The spraying gas Gf employed nitrogen gas at room temperature, and was supplied to the nozzle without heating.

The spray ionization device of Example 2 was applied to the LC device and MS/MS device, a model LC-30 series manufactured by Shimadzu Corp. was used as the LC device, and the model LCMS-8060 manufactured by Shimadzu Corp. was used as the MS/MS device. The spraying gas Gf employed nitrogen gas at room temperature, the sheath gas Gf2employed nitrogen gas, and was supplied to the nozzle with heating.

In Examples 1 and 2, for the interface between the LC device and MS device, it ejects towards the ion capture port of the MS device, and heating of the sprayed droplets was performed by heating the sheath gas.

The spray ionization device of Comparative Example 1 was adopted to the LC device/MS device, a model LC-10 series manufactured by Shimadzu Corp. was used as the LC device, and the model LCMS-2020 manufactured by Shimadzu Corp. was used as the MS device/MS device. The spraying gas Gf used nitrogen gas at room temperature, and was supplied to the nozzle without heating.

The spray ionization device of Comparative Example 2 was applied to the LC device and MS/MS device, a model LC-30 series manufactured by Shimadzu Corp. was used as the LC device, and the model LCMS-8060 manufactured by Shimadzu Corp. was used as the MS/MS device. The spraying gas Gf employed nitrogen gas at room temperature, the sheath gas Gf2employed nitrogen gas, and was supplied to the nozzle by heating. In Comparative Examples 1 and 2, the interface of the LC device and MS device was performed following the specifications of Shimadzu Corp. Heating of the ejected droplets was not performed in Comparative Example 1, and heating of droplets was performed by heating the sheath gas in Comparative Example 2.

In Example 1, Example 2, Comparative Example 1 and Comparative Example 2, the high-voltage power source (supply by mass spectrometer main body) was connected to the gas supply tubes23,123,223, and direct current voltage was applied to the sample liquid at the ion capture port of the MS device or MS/MS device.

Measurement Example 1: Detection of Reserpine

A reserpine solution having a concentration of 1 ppb was introduced in an amount of 1 μL from the injector of the LC device, and a 70% acetonitrile aqueous solution with mobile phase: acetonitrile=3:7 was fed at 400 μL/min as eluent using the LC device. Selective ion monitoring (SIM) analysis was performed by the MS device by ejecting the fed eluent containing sample liquid by the spray ionization devices of Example 1 and Comparative Example 1, and the total area of the peak of the ion signal in the positive ion mode with mass-to-charge ratio m/z=609.3 was measured. Multiple-reaction monitoring (MRM) analysis was performed by the MS/MS device by ejecting the fed eluent containing sample liquid by the spray ionization devices of Example 2 and Comparative Example 2, and the total area of the peak of the ion signal in the positive ion mode with mass-to-charge ratio m/z=609.3>195.0 was measured, for a specific product ion produced by destroying precursor ion. Direct current voltage of +5 kV was supplied to the gas supply tubes23,123,223.

The spraying gas Gf was set to a flowrate of 1.5 L/min in Example 1 and Comparative Example 1, and a flowrate of 2.5 L/min in Example 2 and Comparative Example 2. The sheath gas was heated to 180° C., and the flowrate of 20 L/min was set in Example 2 and Comparative Example 2.

FIG.8A and8Bare graphs illustrating a Measurement Example of reserpine, withFIG.8Abeing a case of Example 1 and Comparative Example 1 not performing heating of the spraying gas, andFIG.8Bbeing a case of Example 2 and Comparative Example 2 performing heating of the sheath gas (180° C.). The vertical axis is the peak area (count number), and by counting the peak area obtained per one measurement and measuring three times, the average value, standard deviation and relative standard device (RSD) (%) (=average value/standard deviation×100) were calculated, and the average value is shown by circles and the standard deviation is shown by error bars inFIG.8.

Referring toFIG.8A, Example 1 was 4.5×104counts; whereas, the Comparative Example was 0.31×104counts. In the Examples, 14 times the signal intensity was obtained in the case of no heat treatment relative to the Comparative Examples, whereby it was found that Example 1 much more efficiently ionized reserpine than Comparative Example 1.

Referring toFIG.8B, Example 2 was 9.2×104counts; whereas, Comparative Example 2 was 8.6×104counts. In Example 2, 1.1 times the signal intensity was obtained in the case of heat treatment relative to Comparative Example 2, whereby it was found that the Examples much more efficiently ionized reserpine than the Comparative Examples.

Measurement Example 2: Detection of Chloramphenicol

A chloramphenicol solution having a concentration of 10 ppb was introduced in an amount of 1 μL from the injector of the LC device, and a 70% acetonitrile aqueous solution with mobile phase: acetonitrile=3:7 was fed at 400 μL/min as eluent using the LC device. SIM analysis was performed by the MS device similarly to Measurement Example 1 by ejecting the fed eluent containing sample liquid by the spray ionization devices of Example 1 and Comparative Example 1, and the total area of the peak of the ion signal in the negative ion mode with mass-to-charge ratio m/z=321.00 was measured. MRM analysis was performed by the MS/MS device by ejecting the fed eluent containing sample liquid to the spray ionization devices of Example 2 and Comparative Example 2, and the total area of the peak of the ion signal was measured in the negative ion mode of mass-to-charge ratio m/z=321.00>152.10. Direct current voltage of −3 kV was supplied to the gas supply tubes23,123,223.

The spraying gas Gf was set to a flowrate of 1.5 L/min in Example 1 and Comparative Example 1, and a flowrate of 1.5 L/min in Example 2 and Comparative Example 2. The sheath gas was heated to 100° C., and the flowrate of 6 L/min was set in Example 2 and Comparative Example 2.

FIG.9A and9Bare graphs illustrating a Measurement Example of chloramphenicol, withFIG.9Abeing a case of Example 1 and Comparative Example 1 not performing heating of the spraying gas, andFIG.9Bbeing a case of Example 2 and Comparative Example 2 performing heating of the sheath gas (100° C.). The vertical axis is the peak area (count number), and shows the average value, standard deviation and RSD, similarly to Measurement Example 1.

Referring toFIG.9A, Example 1 was 1.6×105counts; whereas, Comparative Example 1 was 1.0×105counts. In Example 1, 1.6 times the signal intensity was obtained relative to Comparative Example 1, whereby it was found that Example 1 much more efficiently ionized chloramphenicol than Comparative Example 1.

Referring toFIG.9B, Example 2 was 2.6×105counts; whereas, Comparative Example 2 was 1.9×105counts. In Example 2, 1.4 times the signal intensity was obtained in the case of heat treatment relative to Comparative Example 2, whereby it was found that Example 2 could much more efficiently ionize chloramphenicol than Comparative Example 2.

Measurement Example 3: Detection of Testosterone

A testosterone solution having a concentration of 10 ppb was introduced in an amount of 1 μL from the injector of the LC device, and a 70% acetonitrile aqueous solution with mobile phase: acetonitrile=3:7 was fed at 400 μL/min as eluent using the LC device. SIM analysis was performed by the MS device similarly to Measurement Example 1 by ejecting the fed eluent containing sample liquid by the spray ionization devices of Example 1 and Comparative Example 1, and the total area of the peak of the ion signal in the positive ion mode with mass-to-charge ratio m/z=289.35 was measured. MRM analysis was performed by the MS/MS device by ejecting the fed eluent containing sample liquid to the spray ionization devices of Example 2 and Comparative Example 2, and the total area of the peak of the ion signal was measured in the positive ion mode of mass-to-charge ratio m/z=289.35 >97.20. Direct current voltage of +5 kV was supplied to the gas supply tubes23,123,223.

The spraying gas Gf was set to a flowrate of 1.5 L/min in Example 1 and Comparative Example 1, and a flowrate of 3 L/min in Example 2 and Comparative Example 2. The sheath gas was heated to 180° C., and the flowrate of 14 L/min was set in Example 2 and Comparative Example 2.

FIGS.10A and10Bare graphs illustrating a Measurement Example of testosterone, withFIG.10Abeing a case of Example 1 and Comparative Example 1 not performing heating of the spraying gas, andFIG.10Bbeing a case of Example 2 and Comparative Example 2 performing heating of the sheath gas (180° C.). The vertical axis is the peak area (count number), and shows the average value, standard deviation and RSD, similarly to Measurement Example 1.

Referring toFIG.10A, Example 1 was 2.5×105counts; whereas, Comparative Example 1 was 6.4×104counts. In Example 1, 4.0 times the signal intensity was obtained relative to Comparative Example 1, whereby it was found that Example 1 could much more efficiently ionize testosterone than Comparative Example 1.

Referring toFIG.10B, Example 2 was 3.5×107counts; whereas, Comparative Example 2 was 2.6×107counts. In Example 2, 1.4 times the signal intensity was obtained in the case of heat treatment relative to Comparative Example 2, whereby it was found that the Example 2 could much more efficiently ionize testosterone than Comparative Example 2.

Analysis Device

FIG.11is a diagram schematically illustrating a configuration of an analysis device according to an embodiment of the present invention. Referring toFIG.11, an analysis device400includes the spray ionization device10of the first embodiment or the spray ionization device110of the second embodiment; and an analysis unit401which performs mass spectrometry, etc. by introducing atomized electrically charged droplets from the spray ionization device10,110.

The spray ionization device10,110is selected from among the spray ionization devices10and110of the aforementioned first and second embodiments. The spray ionization device10,110sends to the analysis unit401the electrically charged droplets atomized by the sample liquid Lf being sprayed. The atomized electrically charged droplets are introduced to the analysis unit401in a state in which molecules, clusters, etc. of components contained in the sample liquid are electrically charged by evaporation of solvent.

The analysis unit401, in the case of being a mass spectrometer, has an ion lens, quadrupole mass filter and detector (none illustrated). Ions of the components of the sample liquid Lf generated in the spray ionization device10,110are focused by the ion lens, specific ions are separated based on mass-to-charge ratio by the quadrupole mass filter, detected for every mass number by the detector, and the signals thereof are outputted.

The spray ionization device10,110efficiently generates ions of the components of the sample liquid; therefore, it is possible to use as the ion source of trace amount components. The analysis device400is a liquid chromatography-mass spectrometer (LC/MS) including the spray ionization device10as the ion source.

In the foregoing, the preferred embodiments of the present invention have been described in detail; however, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the present invention described in the claims.

The shape of the cross-section and the channel of the liquid supply tube has been described as circular, but may be triangular, square, pentagonal, hexagonal or other polygonal shapes, or other shapes such as an elliptical shape. The shape of the outer circumferential surface and the inner circumferential surface of the gas supply tube and the second gas supply tube can be selected from these shapes, depending on the shape of the liquid supply tube.

The spray ionization device of each of the aforementioned embodiments can be used as an ion source of various devices; for example, in the field of trace sample analysis, the spray ionization device can be used for mass spectrometry such as mass spectrometry of molecules in a biological sample, elemental analysis, chemical morphology analysis, and charged particle analysis.

The spray ionization devices10and110according to the aforementioned first and second embodiments, by applying to a surface coating apparatus, can form a coating film on the surface of an object by spraying electrically charged droplets of a coating liquid. In addition, the spray ionization devices10and110according to the aforementioned first and second embodiments, by applying to a granulation apparatus, can form particles of components contained in a suspension by spraying electrically charged droplets of the suspension.

In the field of food production, healthcare, and agriculture, the spray ionization devices10and110according to the aforementioned first and second embodiments can be used in space processing utilizing sterilization, deodorization, dust collection, and chemical reactions, utilizing gas-phase or spatial chemical reactions by spraying electrically charged droplets.

EXPLANATION OF REFERENCE NUMERALS