of the liquid supply tube 21.

FIGS. 3A and 3B are cross-sectional views illustrating alternative examples of the gas supply tube of the nozzle of the sprayer. Referring to FIG. 3A, the gas supply tube 42 is preferably formed in the nozzle 45 such that at least a portion 42b2 of the inner circumferential surface 42b thereof has a diameter that progressively decreases toward the outlet 42a, and the opening diameter (D2) of the outlet 42a of the gas supply tube 42 is equal to or smaller than the diameter D1 of the outer circumferential surface 21c of the liquid supply tube, at the tip of the outlet 21a of the liquid supply tube 21 than the outlet 21a. Specifically, the formation satisfies a relationship of D1≥D2. As a result, the flow-focus effect is further enhanced, in which the ejected, atomized and electrically charged droplets can flow at a narrower angle than the case of the nozzle 15 illustrated in FIGS. 2A and 2B.

Referring to FIG. 3B, as another alternative example, the gas supply tube 52 is formed in the nozzle 55 such that: a portion 52b1 of the inner circumferential surface thereof has a diameter that progressively decreases downstream; the diameter of the inner circumferential surface of the gas supply tube 22 is the smallest at a portion 52e, further toward the tip than the outlet 21a of the liquid supply tube 21; and the inner circumferential surface 52b₃has a diameter that progressively increases toward the outlet 52a, further toward the tip than the outlet 21a of the liquid supply tube. An opening diameter D3 of a portion 52e, at which the diameter of the inner circumferential surface of the gas supply tube 52 is the smallest, is formed to be equal to or smaller than the diameter D1 of the outer circumferential surface 21c of the liquid supply tube 21. Specifically, the formation satisfies a relationship of D1≥D3. As a result, the same flow-focus effect as that of the nozzle 45 of FIG. 3A can be achieved, and the content of the sample liquid Lf becomes more unlikely to adhere to the inner circumferential surface 52b₃having a diameter that progressively increases, and clogging becomes more unlikely to occur even in a case of continuous operation for long hours.

Hereinafter, a variation of the sprayer according to the first embodiment of the present invention will be described. In the variation, configurations different from those of the nozzle 15 illustrated in FIGS. 2A and 2B will be described, and the same reference numerals as those in FIGS. 2A and 2B will be assigned to the same configurations, and descriptions thereof will be omitted. The same configurations omitting description achieve the same effects in the variation, in which description of the effects is omitted for the sake of simplicity.

FIG. 4A and FIG. 4B are cross-sectional views of the nozzle of the first variation of the sprayer according to the first embodiment of the present invention, in which FIG. 4A is an enlarged cross-sectional view, and FIG. 4B is a view along arrows Y-Y in FIG. 4A.

Referring to FIGS. 4A and 4B together with FIG. 1, the sprayer of the first variation of the first embodiment includes: the liquid supply tube 21; a gas supply tube 122; a protective tube 127 surrounding the liquid supply tube 21 and provided between the liquid supply tube 21 and the gas supply tube 122; and an electrode 18 for applying high voltage to the sample liquid Lf flowing through the liquid supply tube 21. The electrode 18 has the same configuration as illustrated in FIGS. 2A and 2B. The sprayer has a triple tube structure, in which the tubes are preferably coaxial (central axis X-X) with one another.

The liquid supply tube 21 has the same configuration as the liquid supply tube 21 illustrated in FIGS. 1, 2A and 2B. A second channel 124 of the gas supply tube 122 is a space defined by the outer circumferential surface 127c of the protective tube 127 and the inner circumferential surface 122b of the gas supply tube 122, in which the spraying gas Gf flows through the second channel 124. Note that the spraying gas Gf is not supplied to a space defined by the outer circumferential surface 21c of the liquid supply tube 21 and the inner circumferential surface of the protective tube 127.

In the nozzle 115, a part 122b₁of the inner circumferential face of the gas supply tube 122 is formed so as to progressively decrease in diameter from upstream towards downstream, whereby the channel area of the second channel 124 is formed to gradually narrow.

The tip 127a at the ejection end of the protective tube 127 is located further to the supply end than the outlet 21a of the liquid supply tube 21. In the nozzle 115, a constriction portion 126 of the second channel 124 is formed by the outer circumferential surface 127c of the tip 127a of the protective tube 127 and the portion 122b₁of the inner circumferential surface of the gas supply tube 122. As a result, the second channel 124 is formed such that the channel area of the second channel 124 progressively decreases from the supply end to the constriction portion 126. The spraying gas Gf passes through the constriction portion 126 to gain the flow velocity, and the flow of electrically charged droplets of the sample liquid Lf ejected from the outlet 21a of the liquid supply tube 21 further focuses, promoting atomization of droplets. Furthermore, the droplet ejected from the outlet 21a of the liquid supply tube 21 can be suppressed from flowing back in the second channel 124, and entering the constriction portion 126. As a result, clogging of the constriction portion 126 due to precipitation of components such as salts contained in droplets can be suppressed, whereby stable ejection can be achieved.

The gas supply tube 122 is formed such that the inner circumferential surface 122b2 has a constant diameter (inner diameter) from the constriction portion 126 toward the outlet 122a. As a result, the flow of the spraying gas Gf ejected from the constriction portion 126 is not blocked by any members, whereby turbulence can be suppressed from being generated. The gas supply tube 122 may be formed such that the inner circumferential surface 122b2 of the gas supply tube 122 has a diameter that progressively increases from the constriction portion 126 toward the outlet 122a. As a result, the same effects as in the case of the constant diameter can be achieved.

FIGS. 5A and 5B are cross-sectional views of an alternative example of the gas supply tube of the nozzle of the first variation. Referring to FIG. 5A, the gas supply tube 132 is formed in the nozzle 135 such that: at least a portion 132b₂of the inner circumferential surface has a diameter that progressively decreases from the portion 132d of the constriction portion 126 toward an outlet 132a; and an opening diameter (D5) of the outlet 132a of the gas supply tube 132 is formed to be equal to or smaller than the diameter D4 of the outer circumferential surface 127c of the protective tube 127, further toward the tip than the outlet 21a of the liquid supply tube 21. Specifically, the formation satisfies a relationship of D4≥D5. As a result, the flow-focus effect can be further enhanced, and the ejected, atomized and electrically charged droplets can form a flow at a narrower angle.

As another alternative example, referring to FIG. 5B, the gas supply tube 142 is formed in the nozzle 145 such that: the portion 142b2 of the inner circumferential surface thereof has a diameter that progressively decreases downstream from the portion 142d of the constriction portion 126; the diameter of the inner circumferential surface of the gas supply tube 142 is the smallest at a portion 142e, further toward the tip than the outlet 21a of the liquid supply tube; and the inner circumferential surface 142b3 has a diameter that progressively increases toward the outlet 142a. The opening diameter D6 of the portion 142e, at which the diameter of the inner circumferential surface of the gas supply tube 142 is the smallest, is formed to be equal to or smaller than the diameter D4 of the outer circumferential surface 127c of the protective tube 127. Specifically, the formation satisfies a relationship D4≥D6. As a result, the same flow-focus effect as that of the nozzle 135 of FIG. 5A can be achieved, and the content of the sample liquid Lf becomes more unlikely to adhere to the inner circumferential surface 142b₃, and clogging becomes more unlikely to occur even if an operation is continued for a long time.

In terms of ejecting droplets of the sample liquid Lf in a smaller lateral spreading range with respect to the ejection direction using the flow-focus effect of the flow of the spraying gas Gf, the opening diameter (diameter) of the outlet 21a of the liquid supply tube 21 is preferably smaller than the diameter of the outer circumferential surface 127c of the tip 127a of the protective tube 127 in the constriction portion 126.

FIG. 6 is an enlarged cross-sectional view of the nozzle of a second variation of the sprayer of the first embodiment of the present invention. Referring to FIG. 6, the nozzle 215 of the second variation includes a blocking member 228 along a circumferential direction in a gap between the outer circumferential surface 21c of the liquid supply tube 21 and the inner circumferential surface 127b of the protective tube 127, at the tip 127a toward the ejection end of the protective tube 127. The gap is blocked by the blocking member 228. Except that the closing member 228 is provided, the nozzle 215 has the same configuration as the nozzle 115 of the sprayer of the first variation illustrated in FIGS. 4A and 4B. With this configuration, the blocking member 228 prevents the spraying gas Gf having passed through the constriction portion 126 from entering the gap between the outer circumferential surface 21c of the liquid supply tube 21 and the inner circumferential surface 127b of the protective tube 127. As a result, turbulence of the spraying gas Gf is suppressed from occurring, the flow of electrically charged droplets of the sample liquid Lf focuses, and atomization of droplets is promoted. The blocking member 228 may be provided entirely along the axial direction of the gap between the outer circumferential surface 21c of the liquid supply tube 21 and the inner circumferential surface 127b of the protective tube 127.

SECOND EMBODIMENT

A spray ionization device according to a second embodiment of the present invention has substantially the same configuration as the spray ionization device according to the first embodiment illustrated in FIG. 1, and description of the same elements are omitted.

FIGS. 7A and 7B are cross-sectional views of a nozzle of the spray ionization device according to the second embodiment of the present invention, in which FIG. 7A is an enlarged cross-sectional view of the nozzle, and FIG. 7B is a view along arrows Y-Y shown in FIG. 7A.

Referring to FIGS. 7A and 7B together with FIG. 1, the sprayer of the spray ionization device according to the second embodiment of the present invention includes: a liquid supply tube 21; a gas supply tube 322; and an electrode 18 for applying high voltage to a sample liquid Lf flowing through the liquid supply tube 21. The sprayer has a double tube structure, in which the tubes are preferably coaxial (central axis X-X) with one another. The liquid supply tube 21 has substantially the same configuration as the liquid supply tube 21 of the first embodiment illustrated in FIGS. 1, 2A and 2B. The liquid supply tube 21 includes a first channel 23 defined by the inner circumferential surface of the liquid supply tube 21 and extending in the axial direction. The sample liquid Lf flows through the liquid supply tube 21 and is ejected from an outlet 21a. The gas supply tube 322 has substantially the same configuration as the gas supply tube 22 illustrated in FIGS. 1, 2A and 2B. The gas supply tube 322 includes a second channel 324 defined by the inner circumferential surface 322b of the gas supply tube 322 and the outer circumferential surface 21c of the liquid supply tube 21 and extending in the axial direction. The spraying gas Gfs flows through the second channel 324. The electrode 18 extends from the supply side to the first channel 23 within the liquid supply tube 21 so that the leading end 18a is the same position as the outlet 21a of the liquid supply tube 21 or further towards the supply side than the outlet 21a, and is similar to the configuration shown in FIGS. 1, 2A and 2B.

In the nozzle 315, the outlet 21a of the liquid supply tube 21 of the sprayer is located further toward the supply end than the outlet 322a of the gas supply tube 322. The gas supply tube 322 includes an ejection port 322d between the outlet 322a of the gas supply tube 322 and the outlet 21a of the liquid supply tube 21. The ejection port 322d is a portion in which the diameter of the inner circumferential surface of the gas supply tube 322 is the smallest, and the ejection port 322d is formed narrower than the opening of the outlet 21a of the liquid supply tube 21. For example, the opening diameter of the ejection port 322d is smaller than the opening diameter of the outlet 21a of the liquid supply tube 21. With this configuration, the charged sample liquid Lf ejected from the outlet 21a of the liquid supply tube 21 collides with the spraying gas Gf having flowed through the second channel 324, at high speed in the region between the outlet 21a and the ejection port 322d, whereby the electrically charged droplets of the sample liquid Lf are atomized and ejected from the outlet 322a through the ejection port 322d.

In the nozzle 315, the second channel 324 preferably includes a constriction portion 326 in which the channel area of the second channel 324 is the smallest. The constriction portion 326 is formed by a gap between a portion 322b1, in which the inner circumferential surface 322b of the gas supply tube 322 has a diameter that progressively decreases from upstream to downstream, and the outer circumferential surface 21c of the outlet 21a of the liquid supply tube 21. The spraying gas Gf gains linear velocity in the constriction portion 326 and collides with the sample liquid Lf at high speed in the region between the outlet 21a of the liquid supply tube 21 and the ejection port 322d, whereby atomization of electrically charged droplets of the sample liquid Lf is promoted. The spraying gas Gf is ejected from the constriction portion 326 at high speed; therefore, the content of the sample liquid Lf is unlikely to adhere to the vicinity of the ejection port 322d, and clogging is unlikely to occur. The liquid supply tube 21 is supported in a cantilever manner at the supply end, whereby when the spraying gas Gf is ejected from the constriction portion 326 at high speed, the outlet 21a of the liquid supply tube 21 easily vibrates in a direction perpendicular to the ejection direction. Then, the gap at the constriction portion 326 temporally changes, so that the flow rate of the spraying gas Gf having passed through the constriction portion 326 changes, and the spraying gas flows locally at higher speed. As a result, the content of the sample liquid Lf is further unlikely to adhere to the vicinity of the ejection port 322d, and clogging is further unlikely to occur.

Hereinafter, a variation of the sprayer according to the second embodiment of the present invention will be described. In the variation, configurations different from the nozzle 315 illustrated in FIGS. 7A and 7B will be described, the same reference numerals as in FIGS. 7A and 7B or FIGS. 2A and 2B will be assigned to the same configurations, and description thereof will be omitted. The same configurations omitting description achieve the same effects in the variation, in which description of the effects is omitted for the sake of simplicity.

FIGS. 8A and 8B are views illustrating a nozzle of a first variation of the sprayer according to the second embodiment of the present invention, in which FIG. 8A is an enlarged cross-sectional view, and FIG. 8B is a view of the nozzle from the ejection end.

Referring to FIGS. 8A and 8B together with FIG. 1, the sprayer of the first variation of the second embodiment includes a liquid supply tube 21, a gas supply tube 422, and an electrode 18 for applying high voltage to the sample liquid Lf flowing through the liquid supply tube 21. The electrode 18 has the same configuration as illustrated in FIGS. 1, 2A and 2B. The sprayer has a double tube structure, in which the tubes are preferably coaxial (central axis X-X) with one another.

The gas supply tube 422 includes a second channel 424 defined by the inner circumferential surface 422b of the gas supply tube 422 and the outer circumferential surface 21c of the liquid supply tube 21 and extending in the axial direction. The spraying gas Gf flows through the second channel 424 and is ejected from the outlet 422a in the nozzle 415.

In the nozzle 415, a reticulated member 430 is provided to the outlet 422a of the gas supply tube 422. The reticulated member 430 is retained by a retaining member 422h and arranged so as to cover the opening of the outlet 422a of the gas supply tube 422. For example, a sheet-like mesh sheet can be used for the reticulated member 430. A dielectric material can be used for the mesh sheet, and for example, nylon fiber can be used.

The reticulated member 430 has horizontal lines 430x and vertical lines 430y with an interval of 70 μm, for example, in which a vertical and horizontal size of each aperture is 35 μm, for example. The distance between the outlet 21a of the liquid supply tube 21 and the reticulated member 430 is set to 100 μm, for example, and is preferably set to 5 μm to 300 μm.

With this configuration, electrically charged droplets of the sample liquid Lf ejected from the outlet 21a of the liquid supply tube 21 together with the spraying gas Gf having flowed through the second channel 424 collides with the reticulated member 430 at high speed, whereby the electrically charged droplets of the sample liquid Lf are atomized in the region between the outlet 21a and the reticulated member 430, and ejected through the opening of the reticulated member 430 by way of the spraying gas Gf.

FIG. 9 is an enlarged cross-sectional view of a nozzle of a second variation of the sprayer of the second embodiment of the present invention. Referring to FIG. 9 together with FIG. 1, the second variation of the sprayer of the second embodiment includes a liquid supply tube 21, a gas supply tube 522, and an electrode 18 for applying high voltage to the sample liquid Lf flowing through the liquid supply tube 21. The electrode 18 has the same configuration as illustrated in FIGS. 1, 2A and 2B. The sprayer has a double tube structure, in which the tubes are preferably coaxial (central axis X-X) with one another.

The liquid supply tube 21 has the same configuration as the liquid supply tube 21 of the second embodiment illustrated in FIGS. 7A and 7B, and the sample liquid Lf is ejected from the outlet 21a in the nozzle 515. The gas supply tube 522 includes a second channel 524 defined by the inner circumferential surface 522b of the gas supply tube 522 and the outer circumferential surface 21c of the liquid supply tube 21 and extending in the axial direction. The spraying gas Gf flows through the second channel 524 and is ejected from the outlet 522a in the nozzle 415.

In the nozzle 515, the inner circumferential surface 522b of the gas supply tube 522 has a diameter that decreases at a portion 522k further toward the tip than the outlet 21a of the liquid supply tube 21, and the inner circumferential surface 522b1 is bent perpendicularly to the X-axis direction. A bent portion 524k bent toward the outlet 21a of the liquid supply tube 21 is formed in the second channel 524. As a result, the spraying gas Gf flows toward the outlet 21a of the liquid supply tube 21 at the bent portion 524k, and collides with the sample liquid Lf at high speed in the region between the outlet 21a and an ejection port 522d, whereby the electrically charged droplets of the sample liquid Lf are atomized.

The inner circumferential surface 522b1 of the gas supply tube 522 is bent perpendicularly to the X-axis direction, or may be bent at an angle that is larger or smaller than the vertical angle, depending on the flow velocity or the like of the spraying gas Gf. The spraying gas Gf enters the inside of the liquid supply tube 21 from the outlet 21a and collides with the electrically charged droplets of the sample liquid Lf, whereby atomization of the electrically charged droplets of the sample liquid Lf is promoted.

The ejection port 522d may be provided with the reticulated member 430 of the sprayer of the first variation illustrated in FIGS. 8A and 8B. As a result, atomization of electrically charged droplets of the sample liquid Lf is further promoted.

As a further variation of the sprayer of the spray ionization device according to the second embodiment of the present invention, a second gas supply tube may be provided so as to surround the gas supply tube with a gap.

FIG. 10 is a diagram schematically illustrating a configuration of another variation of the spray ionization device according to the second embodiment of the present invention. Referring to FIG. 10, a spray ionization device 610 includes a second gas supply tube 628 in which a sprayer 611 surrounds a gas supply tube 322, and the nozzle 315 is the nozzle 315 illustrated in FIGS. 7A and 7B. In the second gas supply tube 628, a cylinder 613 supplies sheath gas Gf₂via a valve 616 to a supply port 628s of.

The second gas supply tube 628 includes a third channel 629 defined by an outer circumferential surface 322c of the gas supply tube 322 and an inner circumferential surface 628b of the second gas supply tube 628 and extending in the axial direction. The inner circumferential surface 628b of the second gas supply tube 628 is formed so as to have a constant diameter toward an outlet 628a. The flow of sheath gas Gf₂flowing through the third channel 629 is restricted from spreading by the inner circumferential surface 628b of the second gas supply tube 628 toward the outlet 628a, and the atomized and electrically charged droplets ejected from the nozzle 315 are enveloped in the sheath gas Gf₂. As a result, the outlet 628a of the second gas supply tube 628 ejects the focused, atomized and electrically charged droplets along the axis in the ejection direction. With this configuration, even if the nozzle 315 cannot eject atomized droplets with sufficient focusing thereof, the sprayer 611 can eject focused and atomized droplets.

A heating unit 619 may be provided downstream of the valve 616 so 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 outlet 322a of the gas supply tube 322 so as to surround a second gas supply tube 628. As a result, desolvation of droplets can be supported.

The sprayer 611 can employ the nozzle 415 illustrated in FIGS. 8A and 8B or the nozzle 515 illustrated in FIG. 9, whereby the same effects as the nozzle 315 can be achieved.

The sprayer 611 may employ the nozzle 15 illustrated in FIGS. 2A and 2B, the nozzle 45 or 55 illustrated in FIGS. 3A and 3B, the nozzle 115 illustrated in FIGS. 4A and 4B, the nozzle 135 or 145 illustrated in FIGS. 5A and 5B, or the nozzle 215 illustrated FIG. 6 of the first embodiment.

FIG. 11 is a diagram schematically illustrating a configuration of the alternative example of the second gas supply tube of another variation of the spray ionization device. Referring to FIG. 11, a second gas supply tube 728 of a sprayer 711 of a spray ionization device 710 has the same configuration as the second gas supply tube 628, except that the tip shape of the second gas supply tube 728 differs from the tip shape of the second gas supply tube 628 illustrated in FIG. 10. An inner circumferential surface 728b of the second gas supply tube 728 is formed to have a diameter that progressively decreases toward an outlet 728a, and the channel area of a third channel 729 progressively decreases accordingly.

The sheath gas Gf₂flowing through the third channel 729 flows toward the outlet 728a such that the flow focuses while being restricted by the inner circumferential surface 728b of the second gas supply tube 728. The atomized and electrically charged droplets ejected from the nozzle 315 are enveloped in the sheath gas Gf₂and focus onto the axial center along the ejection direction, and the focused, atomized and electrically charged droplets are ejected from the outlet 728a of the second gas supply tube 728. With this configuration, even if the nozzle 315