JP2010066158A - Syringe, and infusion sample introducing device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress an effect of mass spectrometry by an air bubble produced in a sample introducing syringe when infusion is analyzed. <P>SOLUTION: A conductive liquid contact surface such as a conductive film 21c is provided on a part of the inner surface of the barrel 21 or the plunger 22 of the syringe 20 for infusion analysis, which is grounded. The suction and delivery outlet 21a that faces down is arranged using the syringe 20 and an infusion sample introducing device is formed using a non conductive material to all liquid contacting portions A on the pipe lines from the suction and delivery outlet 21a to an ESI probe 10. With the configuration above, air bubbles produced by electrolysis rises in the barrel 21. Thus, air bubbles do not mix into a liquid sample discharged from the suction and delivery outlet 21a located at the lower side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a syringe for directly introducing a liquid sample into a mass spectrometer of a liquid chromatograph / mass spectrometer (hereinafter, LC / MS) using a syringe, and an infusion sample introduction apparatus using the syringe.

  LC / MS is a combined analyzer in which a liquid chromatograph and a mass spectrometer are connected via an ionization interface. As a typical ionization interface, an electrospray ionization interface (ESI) that ionizes a sample using a high electric field is used. ) In LC / MS, there is an analysis method called infusion analysis in which a liquid sample is directly introduced into a mass spectrometer by a syringe without passing through a liquid chromatograph.

FIG. 3 shows a syringe for infusion analysis coupled to the conventional ESI principle configuration.
As shown in the figure, a liquid sample is introduced from a liquid sample connection port 11 into a metal capillary 15 held along the axial center of a hollow cylindrical nozzle cylinder 13 having a nozzle hole 13a at its tip. A nebulizer gas such as nitrogen is introduced into the nozzle cylinder 13 through the nebulizer gas introduction pipe 12, and is ejected from the nozzle hole 13a. Thereby, a liquid sample is sprayed from the tip of the capillary 15 located in the vicinity of the nozzle hole 13a. A high voltage is applied to the nozzle cylinder 13 by a high-voltage power supply 16, and the capillary 15 connected therewith is also at a high potential, so that the sprayed droplets are charged. After spraying, the charged droplets are further refined and ionized, but the process of ionizing the droplets is described in detail in Patent Document 1 and is omitted here.
The nozzle cylinder 13 is covered with an insulating cover 14 except for the tip, and forms the ESI probe 10 which is the main part of ESI.

The syringe 20 includes a glass barrel 21 in which a metal needle 23 is attached to a suction / discharge port 21 a at the tip, and a plunger 22 that slides while closely fitting the inner wall of the barrel 21. The plunger 22 includes a metal plunger head 22a having a sliding surface and a front surface covered with a plunger seal 22b made of a soft elastic material, and a metal plunger rod 22c connected to the plunger head 22a. The plunger 22c is pushed in, Alternatively, operations such as suction and discharge are performed by pulling out.
A metal flange 21 b is provided at the end of the barrel 21.

  The needle 23 is connected to the liquid sample connection port 11 of the ESI probe 10 by a conduit 24 connected through a metal coupling 25. As the conduit 24, a tube made of PEEK resin having excellent chemical resistance is usually used.

  In the above-described conventional configuration, by pushing the plunger rod 22c, the liquid sample accommodated in the syringe 20 is introduced into the ESI probe 10, and the ionized sample is guided to a mass analyzer (not shown) for infusion analysis. . The operation of pushing the plunger rod 22c may be manual, but is usually operated at a constant speed by a motor-driven actuator (not shown). A device including the actuator, the syringe 20 and the conduit 24 is an infusion sample introduction device.

When the infusion analysis is performed and the liquid sample contains an electrolyte, a high voltage is applied to the metal needle 23 and the coupling 25 through the conductive liquid sample from the capillary 15 to which a high voltage is applied, causing discharge. There is a risk of electric shock. As a countermeasure against this problem, as shown in the figure, the coupling 25 (and the needle 23 electrically connected to the coupling 25) is generally grounded.
JP 2007-227254 A

In the above configuration, the capillary to which a high voltage is applied is one electrode, and the grounded needle is the other electrode, so that electrolysis occurs and bubbles may be generated in the liquid sample in the needle. Since the bubbles are introduced into the ESI probe while mixed in the liquid sample, the spray state becomes unstable, and adverse effects such as noise in the mass analysis appear.
The present invention has been made in view of such circumstances, and provides an infusion sample introduction device that suppresses the influence of air bubbles generated in a sample introduction syringe upon infusion analysis on mass spectrometry, and a syringe used therefor. For the purpose.

In order to solve the above-mentioned problems, the present invention provides a conductive wetted surface on the barrel inner surface of the syringe for infusion analysis or a part of the plunger and grounds it. In addition, an infusion sample introduction device using the above-described syringe, with the suction / discharge port facing downward, and using a non-conductive material for all the liquid contact parts of the pipeline from the suction / discharge port to the ESI Constitute.
With the above configuration, bubbles generated by electrolysis are generated and raised in the barrel, so that bubbles are not mixed in the liquid discharged from the suction / discharge port located below.

  Since the present invention is configured as described above, infusion analysis can be performed without being affected by bubbles generated by electrolysis.

The device of the present invention uses a syringe in which a conductive wetted surface is provided on the inner surface of the barrel or a part of the plunger and grounded, and the suction and discharge ports are directed downward, and all wetted parts are nonconductive. This is a device for introducing a liquid sample into the ESI through a conduit made of material.
Hereinafter, the best mode of the present invention will be described in Example 1.

FIG. 1 shows an embodiment of the present invention. In this figure, the same components as those in FIG. 3 (including functionally identical components) are denoted by the same reference numerals, and the description thereof will be omitted.
The first embodiment is different from the conventional example shown in FIG. 3 in that a conductive film 21c is provided on the inner wall of the barrel 21 of the syringe 20. Specifically, the conductive film 21c is, for example, a vapor-deposited film of metal such as gold or nickel, and is provided in a strip shape over the entire length of the barrel 21 from the inner wall at the tip of the barrel 21 to the flange 21b at the end. Therefore, if there is a liquid in the barrel 21, it always comes into contact with the liquid. Moreover, since it is electrically connected to the metal flange 21b, if the flange 21b is grounded, the conductive film 21c is also grounded.

  The second difference is that the syringe 20 is arranged with the suction / discharge port 21a facing downward, and the third is a tube connecting the suction / discharge port 21a and the liquid sample connection port 11 of the ESI probe 10. That is, all the wetted parts A of the path are made of a non-conductive material. Here, the liquid contact part A is a general term for a part in contact with the liquid sample. For example, the inner wall surface of the conduit 24 is the liquid contact part A as shown in the figure. The conduit 24 is made of resin as well as non-conductive, but the coupling 26 that connects the conduit 24 to the suction / discharge port 21a is also molded with resin (for example, PEEK) so that all the liquid contact parts A are non-conductive. Have sex.

  In the above-described configuration, by pushing the plunger rod 22c, the liquid sample is introduced into the ESI 2 through the conduit 24, sprayed from the nozzle hole 13a at the tip of the ESI probe 10, ionized, and introduced into the mass analyzing unit 1, and mass analysis is performed. What is done is the same as before. In this process, electrolysis occurs using the grounded conductive film 21 c as one electrode, and bubbles are generated in the liquid sample in the barrel 21. Since the generated bubbles rise in the barrel 21, the bubbles are not mixed in the liquid sample discharged from the suction / discharge port 21a located below. Further, since there is no conductive wetted part that can be an electrode in the conduit 24 or the coupling 26, no bubbles are generated in these parts.

FIG. 2 shows a modification of the present invention. Although only a part of the syringe 20 is shown in the figure, the part not shown and the overall configuration are the same as those in FIG. Moreover, what attached | subjected the same code | symbol as FIG. 1 or FIG. 3 in the same figure is the same thing (a functional same thing is included), and abbreviate | omits description here again.
FIG. 2A shows a structure in which the exposed metal surface 22d is formed by exposing the metal surface without covering the front surface of the metal plunger head 22a with the plunger seal 22b. Since the exposed metal surface 22d is in contact with the liquid sample in the barrel 21 and is grounded via the plunger rod 22c, electrolysis occurs using the exposed metal surface 22d as one electrode, and bubbles are generated in the vicinity thereof. No air bubbles enter the lower suction / discharge port 21a. When it is necessary to improve chemical resistance, the exposed metal surface 22d may be plated with gold.

  In FIG. 2B, a metal screw 22e penetrating the plunger seal 22b is screwed into the plunger head 22a, and the surface thereof is a conductive wetted surface similar to the exposed metal surface 22d in FIG. The operation is also substantially the same as in the case of FIG.

The present invention is not limited to the above-described embodiment, and various other modifications can be given.
For example, the syringe 20 does not need to be installed vertically and may be inclined obliquely. In this case, however, it is a necessary condition that the suction / discharge port 21a is directed downward. By inclining obliquely, for example, in the modified example of FIG. 2A, the problem that the exposed metal surface 22d does not come into contact with the liquid when air enters the barrel 21 is solved.
Also, the conduit connecting the syringe 20 and the ESI probe 10 may be connected to the conduit 24 via the needle 23 and the coupling 25 as in the conventional example of FIG. However, in this case, it is necessary to use the needle 23 and the coupling 25 made of resin or at least the liquid contact surface coated with resin or the like.

  The present invention can be used for mass spectrometry.

It is a figure which shows one Example of this invention. It is a figure which shows the other Example of this invention. It is a figure which shows the conventional structure.

Explanation of symbols

1 Mass Spectrometer 2 ESI
10 ESI probe 11 Liquid sample connection port 12 Nebulizer gas introduction tube 13 Nozzle cylinder 13a Nozzle hole 14 Insulation cover 15 Capillary 16 High voltage power supply 20 Syringe 21 Barrel 21a Suction discharge port 21b Flange 21c Conductive film 22 Plunger 22a Plunger head 22b Plunger seal 22c Plunger rod 22d Exposed metal surface 22e Screw 23 Needle 24 Conduit 25 Coupling 26 Coupling A Liquid contact part

Claims (2)

  An inner surface of the barrel, in a syringe that includes a cylindrical barrel having an inlet / outlet at one end and a plunger that slides in close contact with the inner wall of the barrel and that sucks and discharges liquid into the barrel by the movement of the plunger. Alternatively, the syringe has a conductive liquid contact surface that is in contact with the liquid in the barrel and is electrically connected to the outside of the syringe at a part of the plunger. The syringe according to claim 1 is used, the suction / discharge port of the syringe is disposed downward, and all the liquid contact parts of the pipe line connecting the suction / discharge port and the electrospray ionization interface are non-conductive. Infusion sample introduction device composed of a conductive material.

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