JP6060779B2 - Capillary cell connector and ferrule used therefor - Google Patents

Description

  The present invention relates to a capillary cell connector for connecting a capillary cell used in a detector such as a liquid chromatograph (LC) and a sample liquid feeding pipe, and a ferrule used therefor.

  The liquid chromatograph apparatus includes a liquid feed pump, a sample liquid feed pipe, a sample line injector, a separation column, a detector, and the like (see, for example, Patent Document 1).

  In this apparatus, as shown in FIG. 3, the mobile phase stored in the mobile phase container 31 is sucked at a constant flow rate by the liquid feed pump 32, pressurized to a high pressure, and fed to the separation column 34. The sample line injector 33 injects a liquid sample into the mobile phase. The injected liquid sample is introduced into the separation column 34 together with the mobile phase, and is separated into each component while passing therethrough. The separated components are sent to the detector 35 through the sample feeding pipe 36.

  In the detector 35, each component sent from the sample liquid feeding pipe 36 is introduced into the capillary cell 37, light is emitted from the light source 35a, and the transmitted light is detected by the photodetector 35b. The capillary cell 37 has a small inner diameter (for example, 1 mm or less) so as to reduce the amount of mobile phase in order to cope with trace component analysis.

  Thus, the capillary cell with a small inner diameter (hereinafter simply referred to as “capillary”) and the sample feeding pipe are connected using a connecting member at a location surrounded by a wavy line in FIG. As described above, since the mobile phase passes through the capillary at a high pressure, if there is a gap between the connecting member and the capillary, the liquid sample and the mobile phase (liquid sample or the like) leak to the outside. For this reason, the connecting member and the capillary need to be sufficiently liquid-tightly connected.

  FIG. 4a) shows a connecting member, which is arranged at a location surrounded by a wavy line in FIG. The connecting member 40 includes a liquid feeding pipe insertion port 47 into which the sample liquid feeding pipe 36 is inserted, a capillary insertion port 46 into which the capillary 37 is inserted, and a communication portion 45 that connects the two. Of these, the capillary insertion port 46 has a tapered portion that increases in diameter toward the opening side. A part of the connecting member 40 is composed of a light transmitting member 48 so that the capillary 37 can be irradiated with light.

  As shown in FIG. 4b), when the tip of the capillary 37 is inserted into the capillary insertion port 46, first, a ferrule 43 made of a tapered resin or the like is fitted on the outer periphery of the capillary, and the capillary insertion port 46 is in that state. Insert into. Thereafter, the fixing member 44 is pressed toward the back from the inlet of the capillary insertion port 46, and the ferrule 43 is pressed against the tapered portion of the capillary insertion port 46 to be fixed.

  It is difficult to make the inclination of the taper of the ferrule 43 and the inclination of the taper portion of the capillary insertion port 46 exactly the same. Therefore, conventionally, as shown in FIG. 5, the taper of the ferrule 43 is slightly inclined so that the ferrule 43 and the capillary 37 are in line contact with each other at the tip of the taper of the ferrule 43, thereby ensuring liquid tightness. I was trying to do it.

JP 2010-48554 A

However, in the above-described structure, as shown in FIG. 5, a location where the tip outer periphery of the ferrule 43 receives a force from the tapered surface of the capillary insertion port (A ′) and a location where the tip inner periphery of the ferrule 43 tightens the capillary 37 (B ') Is almost the same position on the capillary axis. Therefore, the force pressed from the tapered surface of the capillary insertion port 46 is transmitted to the capillary 37 as it is through the vertical surface of the ferrule tip, and a vertical shearing force is applied to the capillary 37 at that location. For this reason, the conventional connection structure has a problem that breakage (guillotine breakage) is likely to occur at a specific portion of the tip of the capillary 37.
In particular, when a capillary made of glass and having a thin inner wall must be used, the above problem has become apparent.

The ferrule according to the present invention formed to solve the above problems is a funnel-shaped ferrule attached to the outer periphery of the capillary when the capillary used in the liquid chromatograph apparatus and the sample liquid feeding pipe are connected. There,
A tapered portion with a small diameter on the tip side;
A cylindrical portion provided at the tip of the tapered portion and in contact with the outer peripheral surface of the capillary,
The bent portion between the cylindrical portion and the tapered portion on the inner peripheral surface is shifted to the tip side from the bent portion between the cylindrical portion and the tapered portion on the outer peripheral surface. And

Further, a capillary cell connector according to the present invention made to solve the above problems is a capillary cell connector for connecting a capillary cell used in a liquid chromatograph apparatus and a sample liquid feeding pipe,
The above ferrule,
A tapered capillary insertion port having a steeper slope than the tapered portion of the ferrule for inserting the capillary on which the ferrule is mounted; a liquid feeding pipe insertion port for inserting the sample liquid feeding pipe; A connecting member having a communication portion for communicating the capillary insertion port and the liquid feeding pipe insertion port;
A fixing member for pressing and fixing the cylindrical portion of the ferrule into the communication portion by pressing the ferrule toward the back of the capillary insertion port;
It is characterized by providing.

  In the capillary cell connector configured as described above, when the ferrule is attached to the outer periphery of the capillary and is pushed toward the back of the capillary insertion port by the fixing member, the bent portion on the outer peripheral surface of the ferrule becomes the boundary between the communication portion and the capillary insertion port. It is pressed and fixed. At this time, since the bent portion on the inner peripheral surface of the ferrule is displaced toward the tip side of the ferrule from the bent portion on the outer peripheral surface, the ferrule and the capillary are in a plane perpendicular to the capillary from the bent portion on the outer peripheral surface. A space is created between Therefore, the force received from the boundary by the bent portion on the outer peripheral surface is not applied as it is as a shear force perpendicular to the capillary.

  Here, the cylindrical portion and the tapered portion of the ferrule may be made of resin.

  By doing so, the bent portion on the inner peripheral surface receives a force, whereby the ferrule bends due to the elasticity of the resin, and the force is relaxed and transmitted to the capillary. Further, since the cylindrical portion of the ferrule is in surface contact with the capillary, the liquid tightness is also improved.

As described above, if the capillary and the sample liquid feeding pipe are connected using the capillary cell connector of the present invention, it is possible to prevent the capillary from being damaged due to a vertical shearing force applied to the capillary.
Further, since the cylindrical portion of the ferrule is in surface contact with the capillary, the sealing area is widened and the sealing pressure is made uniform as compared with the conventional line contact structure, thereby improving the liquid tightness.
Further, since the cylindrical portion of the resin ferrule is bent to embrace the capillary, even if the fixing member is inadvertently pressed, the force is alleviated by the bending. Therefore, push-in adjustment becomes easy.

The drawing which shows the outline | summary of the ferrule and connector for capillary cells of this invention. (a) shows a connecting member, and (b) shows a state in which a capillary cell and a sample feeding pipe are connected. The figure which shows the front-end | tip of the ferrule of this invention, and its periphery when a capillary cell is fixed to a connection member. Drawing which shows the outline | summary of a liquid chromatograph apparatus. The figure which shows the outline | summary of the connection structure of the conventional capillary cell and a sample liquid feeding pipe. (a) shows a connecting member, and (b) shows a state in which a capillary cell and a sample feeding pipe are connected. Drawing which shows the outline | summary of the capillary tip in the conventional connection structure, and its peripheral structure.

  Hereinafter, an example of a capillary cell connector according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a drawing showing an outline of a ferrule and capillary cell connector (hereinafter simply referred to as “connector”) according to the present invention. The connector includes a connecting member 10, a ferrule 13, and a fixing member 14.

  As shown in FIG. 1a), the connecting member 10 includes therein a tapered capillary insertion port 16, a liquid feeding pipe insertion port 17, and a communication portion 15 that communicates these. A part of the connecting member 10 is composed of a light transmitting member 18 so that the capillary 12 can be irradiated with light. As shown in FIG. 1 b, the resin ferrule 13 is inserted into the capillary insertion port 16 together with the capillary 12 while being mounted on the outer periphery of the capillary 12. The fixing member 14 is a nut made of stainless steel (SUS) and is fastened to the opening side end of the capillary insertion port 16.

  The connecting member 10 and the sample liquid feeding pipe 11 are also made of stainless steel, and the tip of the sample liquid feeding pipe 11 and the liquid feeding pipe insertion port 17 are welded in advance to ensure the liquid-tightness of both. The outer diameter of the sample liquid feeding pipe 11 is 0.8 mm (inner diameter 0.1 mm).

  The capillary 12 is made of quartz glass, and its outer diameter is 0.5 mm (inner diameter 0.36 mm), which is thinner than the sample liquid feeding pipe 11. This is to enable trace component analysis by reducing the amount of mobile phase and improving separation performance.

  The nut 14 is used for tightening from the opening side of the capillary insertion port 16 to push the ferrule 13 into the connecting member 10 and fix it.

  The connector according to the present invention is characterized by a resin ferrule 13. The ferrule 13 has a tapered portion 13a having a small diameter on the tip side and a cylindrical portion 13b provided at the tip of the tapered portion 13a (FIG. 2).

  Since the inner diameter of the cylindrical portion 13 b is slightly larger than the outer diameter of the capillary 12, the cylindrical portion 13 b is inserted into the communicating portion 15 with the inner peripheral surface of the cylindrical portion 13 b in contact with the outer peripheral surface of the capillary 12 tip. Further, the thickness of the cylindrical portion 13b is substantially the same as the gap between the communication portion 15 and the capillary 12, and for example, the inner diameter of the communication portion 15 at the position where the tip of the capillary 12 is inserted is 1.0 mm. In this case, the thickness of the cylindrical portion 13b is preferably about 0.25 mm.

  The tapered portion 13 a transmits a force with which the nut 14 pushes the ferrule 13 to the cylindrical portion 13 b, and the cylindrical portion 13 b is pushed into the communication portion 15. Further, the inclination of the tapered portion 13 a is slightly gentler than the inclination of the tapered portion of the capillary insertion port 16, and can be inserted into the capillary insertion port 16.

  Further, the bent portion (B) on the inner peripheral surface of the ferrule 13 is shifted to the tip side of the ferrule 13 with respect to the bent portion (A) on the outer peripheral surface (FIG. 2).

  When the ferrule 13 is attached to the outer periphery of the capillary 12 and pushed toward the back of the capillary insertion port 16 by the nut 14, the bent portion (A) is pressed against the boundary between the communication portion 15 and the capillary insertion port 16 and fixed. Is done. In this state, the bent portion (A) receives a force from the boundary, and the cylindrical portion 13b tightens the capillary 12 by this force, and thus liquid tightness is secured.

  At this time, the bent portion (B) on the inner peripheral surface of the ferrule 13 is shifted to the distal end side of the ferrule 13 with respect to the bent portion (A) on the outer peripheral surface, so that the bent portion (A) is perpendicular to the capillary 12. A space (C) is formed between the ferrule 13 and the capillary 12 in the lowered plane. Therefore, the force received by the bent portion (A) from the boundary is not directly applied as a shearing force perpendicular to the capillary 12.

  Further, since the ferrule 13 is made of elastic PEEK (registered trademark) resin, when the bent portion (A) receives a force, the ferrule 13 is bent because of the space (C). This acts as a buffer function, and the force received by the bent portion (A) is relaxed and transmitted to the capillary 12.

  Furthermore, since the cylindrical portion 13b is in surface contact with the capillary 12, the liquid tightness is also improved.

  In addition, the gap between the communication portion 15 and the capillary 12 becomes a dead space where a liquid sample or the like that is not analyzed and remains in the gap is present. However, when the cylindrical portion 13b of the ferrule 13 is inserted, the gap becomes dead. Space can be reduced.

10, 40 ... Connecting members 11, 36 ... Sample feeding pipes 12, 37 ... Capillaries (cells)
13, 43 ... Ferrule 13a ... Tapered portion 13b ... Cylindrical portion 14, 44 ... Nut (fixing member)
DESCRIPTION OF SYMBOLS 15, 45 ... Communication part 16, 46 ... Capillary insertion port 17, 47 ... Liquid feeding pipe insertion port 18, 48 ... Light transmission member 31 ... Mobile phase container 32 ... Liquid feeding pump 33 ... Sampling injector 34 ... Separation column 35 ... Detection vessel

Claims (3)

A capillary cell connector for connecting a capillary used in a liquid chromatograph apparatus and a sample feeding pipe,
A funnel-shaped ferrule attached to the outer periphery of the capillary, a connecting member for inserting the capillary attached with the ferrule, and a fixing member for pressing and fixing the ferrule against the connecting member;
With
The ferrule is
A tapered portion with a small diameter on the tip side;
A cylindrical portion provided at the tip of the tapered portion and in contact with the outer peripheral surface of the capillary,
The bent portion between the cylindrical portion and the tapered portion on the inner peripheral surface is shifted to the distal end side than the bent portion between the cylindrical portion and the tapered portion on the outer peripheral surface,
The connecting member is
A capillary insertion port with a small diameter on the tip side;
A liquid feed pipe insertion port for inserting the sample liquid feed pipe;
A communication portion connected at one end to the distal end side of the capillary insertion port and connected to the liquid feeding pipe insertion port at the other end, and communicating the capillary insertion port and the liquid feeding pipe insertion port;
With
The fixing member is
When the ferrule is pressed toward the back of the capillary insertion port, the bent portion of the outer peripheral surface of the ferrule is pressed against the boundary between the communication portion and the capillary insertion port. Is pushed into the communication part and fixed,
Capillary cell connector.   The ferrule used for the connector for capillary cells of Claim 1.   The ferrule according to claim 2, wherein the cylindrical portion and the tapered portion are made of resin.

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