EP2010327A1

EP2010327A1 - Device for collecting liquids

Info

Publication number: EP2010327A1
Application number: EP07724669A
Authority: EP
Inventors: Thomas Best
Original assignee: Dunges Wolfgang
Current assignee: Dunges Wolfgang
Priority date: 2006-04-27
Filing date: 2007-04-27
Publication date: 2009-01-07
Also published as: DE102006020286A1; WO2007124926A1

Abstract

Device for collecting liquids, preferably in the microlitre range, with a container (44), a lid (50) for closing the container (44), said lid (50) having a bore (60), and with a collecting cannula (34) that has a lateral opening (42) at the distal end, wherein the cannula (34) can be displaced sealingly along its longitudinal axis in the bore (60), and the lid (50) has such a thickness that the lateral opening (42) of the cannula (34) is received sealingly in the lid (50) after withdrawal of the cannula (34).

Description

Device for removing liquids

The invention relates to a device for removing liquids, which can be used in particular in the microliter range.

In analytical studies, certain proportions of solvents having an analyte to be assayed are removed from a sample container by means of a syringe, tube or the like. In a multiple sampling these containers must be closed for safe storage of the solution, otherwise there is a risk that the liquid evaporates and thus remain only residues of the analyte to be examined in the container, which usually makes analysis significantly difficult or impossible.

When using a cannula or syringe to remove the analyte or the solvent containing the analyte, containers capped with a cap are frequently used, the cap having a pierceable septum made of an elastic material. These septa close automatically after pulling out the cannula needle, it being assumed that the closure of the septum is vapor-tight, so that no solvent can escape from the container interior. It has now been found that, especially in multiple withdrawals, the septa are not tight, ie evaporate vapor in vapor form through the no longer closing holes in the septum and thus there is a risk that the analyte can not be completely removed again. Furthermore, there is a risk in the septum materials used that they themselves adsorb the solvent, so that again solvent disappears from the container interior with the same consequences described above. This is particularly problematic for sampling in the microliter range, in which only a small amount of liquid (3-10 microliters) is used as solvent. From DE 103 09 348 a removal system is known which consists of a desorption sample container and a needle unit. This container is covered at its frontal opening with an end cap having a through hole. The through-bore of the end cap has a closure made of PTFE with a through-hole through which a trained as a hollow needle or cannula needle unit for sampling is pierceable. In this case, the inner diameter of the through hole is equal to or smaller, preferably slightly smaller than the outer diameter of the needle unit, whereby a sealing effect along the outer circumference of the needle unit comes about upon import of the needle unit.

This known removal system in turn has a pierceable septum in the form of a closure, which is fastened by means of a crimp cap on the container. Once the closure is pierced, the crimp cap and thus the closure is removed, which therefore obviously does not close and thus is only suitable for single use, so for the mere closing of the container.

Consequently, the entire assembly is closed to the environment only when either the closure is intact or the cannula is fully inserted through the extraction unit into the container with the cannula abutting the bore wall of the PTFE body. Once the cannula has been withdrawn, a new closure must again be attached, as stated above, in order to prevent the escape of solvent.

The invention is therefore based on the object to provide a device for the removal of liquids available, in which after the first removal of solution sample loss can be reliably prevented by evaporation of volatile solvent.

The object is achieved by a device for removing liquid, which can be preferably used in the microliter range, which has a container, a lid for closing the container with a bore, and a removal cannula with a lateral opening at the distal end, wherein the cannula sealing, however slidably aufiiehmbar along its longitudinal axis in the bore aufiiehmbar, and the lid has a thickness such that the lateral opening of the cannula when removing the cannula from the container is completely sealed in the lid.

In the arrangement according to the invention, the cannula can be passed through the hole provided in the lid directly into the interior of the container, whereby the lateral opening of the cannula can be in fluid communication with the outside environment after the lid has passed through it. The cannula can then be used to remove solution which is present inside the container. For this purpose, the cannula can be guided to the bottom of the container, wherein almost all the liquid can be absorbed by the Seitenöfmung.

Once a predetermined amount of liquid has been received by the syringe or a connected tube, the cannula is withdrawn until the side opening of the cannula is within the lid. The radial seal around the cannula completely seals the interior of the container from the outside environment.

Advantageously, therefore, the lid has a thickness which is greater than the axial length of the lateral opening of the cannula, preferably twice the length or more. The distance of the lateral opening from the cannula tip is advantageously chosen equal to the diameter of the opening or larger.

According to a first embodiment, the cannula needle itself is directly connected to the syringe body, i. integrally formed.

According to a second embodiment, the cannula needle has a coupling, usually a screw or bayonet coupling with the syringe body. For this purpose, the proximal end of the cannula is provided with a screw coupling unit in the form of a screw cap, which can be screwed onto a complementary screw thread on the syringe body. According to a further, particularly preferred embodiment, a snap coupling is provided between the proximal end of the cannula and the syringe body, which can be used for a quick coupling or decoupling of the cannula with the syringe body. In this latter case, the distal formation of the cannula can be uncritical, ie it can be provided with a lateral bore or else with a front bore. However, this cannula formation can also be used for purposes other than for the purposes of the invention. It is particularly suitable when the sampling system according to the invention is to be operated in conjunction with an automated sample introduction system of an analytical device or in conjunction with a laboratory robot for automated sample preparation.

As a material for the lid, polytetrafluoroethylene (PTFE) is advantageously used, which has the property that it has certain flow / lubricating properties. "Lubricating properties" are understood to mean those properties which reduce the friction between two parts, as a result of which, even when the cannula and the cover bore are tightly fitted, the friction is reduced if PTFE is used as the cover material.

Incidentally, PTFE also has favorable sealing properties, provided it is used in a screw cap for screwing onto a container with a corresponding screw end. For storage of the residual sample with prolonged disuse of the sampling system, the lid can be replaced with the cannula therein, for example, by a conventional lid without bore, the lid is preferably designed screwed to the container and optionally a PTFE disc is used as an additional sealant.

The nominal diameter of the bore or the diameter of the bore of the lid is equal to or slightly smaller than the outer diameter of the cannula. By "minor" is a maximum of 10%, advantageously at most one

5% reduction in the diameter of the bore, based on the outer diameter of the cannula to understand. In a further embodiment, the sampling device additionally has a mechanical safeguard to prevent leaks due to unintentional complete withdrawal of the cannula from the container and undesired contamination by accidentally exchanging the needles belonging to different containers. Such a fuse may for example consist of a spacer having a mounted on the top of the lid linkage or from a nose at the distal end of the cannula. Other embodiments which accomplish the same object are known in the art and skilled in the art.

Further advantages and embodiments of the invention are described in the following drawings.

Show it:

Figure 1 is a schematic cross-sectional view in the parts A-D of a device for withdrawing liquid, wherein

Figure IA illustrates a syringe assembly according to the prior art,

FIG. 1B shows a syringe arrangement which can be used according to the invention,

FIG. 1C shows a cross-sectional view of a cannula, which is provided in a sealed state in a container, with an enlarged partial section, in which the inserted cannula is shown,

Figure 1 C * immersed in the deepest container deepened cannula, and

FIG. 1D, similar to the representation according to FIG. 1C, shows a sealed cannula end in a lid, which is fastened on a container, not shown, FIG. 2 shows a schematic view of the device according to the invention with FIG

Partial views of syringe assemblies, wherein the syringe body is in each case with a coupling piece with a cannula / end coupled, and the cannula is in different arrangements in the container and

Figure 3 shows a Ausftlhrungsungsform of the coupling shown in Figure 2 in cross section in the uncoupled and the coupled position.

In Figure 1, a syringe 10 is shown in the image A according to the prior art, the needle tip 12 is opened. This syringe 10 is formed in one piece and is not suitable for the purposes of the invention, since it can be used only for single use for sampling and then must be discarded.

In Figure IB, a Aufhahmenanordnung 14 is shown in the form of a two-piece syringe assembly 15, which consists of a syringe body 16 with a syringe channel 18 and a scale 20, wherein in the syringe channel 18, a punch 22 is immersed with an actuating member 24. At the opposite end 26 of the syringe body 16 is provided with a screw 28 which has an external thread 30. The syringe channel 18 passes through the screw 28, which is expanded to receive the proximal end 32 of the cannula 34 accordingly. This proximal end 32 in this case has a screw cap 36 with an internal thread which cooperates with the external thread 30 of the syringe body 16 complementary, wherein in the screwed state, the cannula channel 38 is aligned with the syringe channel 18 and forms a flow path.

The actuating member 24 is shown in Figure IB as a handpiece, which allows manual movement of the punch 22. If an automatic dosing system (not shown in the figure) is used, a corresponding connection to the mechanically moving parts of such a system can also be installed at this point.

The distal end 40 of the cannula 34 is closed and either rounded or pointed, but preferably pointed, as shown in particular from the enlarged view of Figure IC and Figure ID is apparent. Adjacent to the distal end, a cannula opening 42 is recessed laterally in the cannula wall, which forms the aforementioned flow path, formed by the cannula channel 38 and the syringe channel 18, to the interior of a container 44.

In Figure ID, the container 44 is not shown in detail, with only the outer wall 46 and the container wall 48 are of interest. On this container 44, a lid 50 is placed, which is designed as a screw cap.

The lid 50 covers the container 44 with its main lid part 52 and thus seals the container in the screwed-on state.

From the main lid part 52 is according to the embodiment shown in Figure 1 axially from a ring member 54 which has on the inside an internal thread 56 which can cooperate with a complementary external thread 58 of the container 44 such that the main lid member 52 sealingly cooperates with the container 44. This is illustrated in particular in the enlargement according to FIG.

The main lid portion 52 is penetrated with a bore 60 which creates a flow connection from the environment to the container interior 48. Through the bore 60, the cannula 34 can be pushed through, wherein it can be locked according to the enlarged views in Figure 1 either in the lid 50 or, as shown in Figure IC *, is advanced to the deepest container.

The nominal diameter or diameter of the bore 60 is designed so that it corresponds at most to the outer diameter of the cannula 34. Advantageously, the nominal diameter is somewhat smaller, but not more than 10% of the nominal diameter of the cannula 34.

This ensures that the cannula fits snugly, but without having to be displaced in the container 44 with considerable force. As shown in the enlargement of Figure IC or Figure ID, the thickness x of the main lid portion 52 is at least twice as large as the diameter y of the lateral cannula opening 42, advantageously more than three times. This ensures that the cannula 34 can be adjusted to seal the container 44 with respect to the environment without difficulty. This is especially true for an automatic feeding and retracting the syringe assembly 14 by means of a dosing, not shown.

The material of the cover 50 is advantageously made of PTFE, on the one hand sufficiently rigid to produce a satisfactory sealing effect with the container 44, but has excellent sliding properties, so that the cannula 34 only with low friction, even with tight tolerances of the bore 60 in the container can be pushed, but not jammed in the bore 60.

Essential to the invention is therefore that the lateral opening 42 closes the container interior tightly against the environment over a longer period with locked opening 42 in the main lid part 52, so that no volatile solvents can escape from the container 44.

FIG. 1C shows a special container arrangement which has a microliter vessel 62, to which a reflux pipe 64 adjoins. This microliter vessel 62 is accommodated in a further vessel 66, which receives by means of a tubular adapter 68, the microliter vessel 62 with its return pipe 64 in sealingly. In this case, the tube 64 is arranged in alignment with the bore 60, so that, as shown in the right-hand enlarged view of Figure IC *, the cannula tip are pushed into the deepest of the container and from there can absorb the solution to be examined 70. For example, in the enlarged embodiment, volumes in microliter vessel 62 are on the order of 3-10 μl.

In FIG. 2, syringe arrangements in different coupled states are shown in steps 1 to 5, the reference symbols according to FIG. 1 being used for the same parts. As can be seen from FIG. 2, instead of a screw piece 28, the syringe arrangement 14 has a coupling part 70, which can interact in a complementary manner with a coupling piece 72. This coupling piece 72 is in turn connected to the screw flap 36 by means of an external thread 74, but may also be permanently connected to the cannula 34.

The first and second coupling parts 70 and 72 are shown and described in detail in FIG.

An inventive coupling piece 70, 72, which is shown in Figure 3 and corresponds to the coupling piece of Figure 2, connects the syringe body 16 of Figure 1 releasably connected to the syringe needle 12 while avoiding the above-mentioned screw closure undoing the nut 36 on the threaded insert 30. Rather, allows the snap coupling 70, 72, if necessary, the smooth change of the removable syringe needle 12th

The snap-in coupling 70, 72 according to the invention comprises a plug-type insert part 80 and a socket-like receiving part 82 for receiving the plug-type insert part 80, which each form rotationally symmetrical components.

The insert 80 has on the coupling side a cylindrical pin 84 which is inserted into the socket 82 for engagement. At its body-side end of the insert 80 is provided with a central threaded bore 86 through which the insert 80 is connected to the corresponding attached to the syringe body 16 threaded attachment 30. From the threaded bore 86, a through hole 88 extends to the coupling end of the plug 80, in which a Korpuskapillare 89 is arranged to receive the syringe channel 18. The pin 84 is provided in the region of its coupling-side end with a circumferential recess 85 which serves the locking of the pin 84 with the sleeve 82. The Aufiiahmeteil 82 for receiving the male insert 80 has at its end facing away from the insert 80 a threaded pin 90, to which the union nut 36 of the syringe needle 12 is releasably attached. Inside the sleeve 80, a connection capillary 92 for receiving the syringe channel 18 is arranged, which is guided at the opening end of the sleeve 82 by a displaceable in the direction of the longitudinal axis of the sleeve 82 guide ring 94 and disposed at the other end of the sleeve 82 in a through hole 96 which extends inside the sleeve 82 from the bottom thereof to the syringe-side end thereof. The syringe-side end of the sleeve 82 has a threaded pin 90 which is screwed to the nut 36. In the interior of the bushing 82, locking means in the form of balls or rings 102 are circumferentially arranged in the region of their opening-side end on the inner wall side, which are enclosed by the guide ring 94 in the unlocked or disengaged state of the snap-in coupling. For locking the pin 84 with the sleeve 82 of this guide ring 94 is moved in the direction of the syringe needle 12 exposing the balls 102 and the pin 84, the sleeve 82 is inserted so that the balls 102 can engage in the recess 85.

FIG. 2 now shows the removal of liquid with the syringe arrangement 14 in the steps 1-5.

In step 1, as shown in the enlarged view of the lid 50, the tip of the cannula 34 is located in the bore 60 such that the cannula opening 42 is in the main lid portion 52 so that the container 44 is sealed against the environment.

In step 2, the two coupling parts 70 and 74 are coupled, as shown at A.

In step 3, the syringe assembly 14, including the cannula 34, is advanced into the deepest of the container, as can be seen, for example, in Figure 1C * in the enlarged view. Subsequently (step 4), a predetermined amount of liquid is first drawn up, as by the retracted punch 22 in step 4 can be seen. Subsequently, the syringe assembly 14 is retracted so far until the Kanülenöffiiung 42 again in the lid 50 is sealing. With the actuating step B, the decoupling of the two coupling parts 70 and 72 is shown, wherein the actual decoupled state in step 5 can be seen. The syringe body 15 is now filled with a predetermined amount of liquid to be examined and is then connected to an analyzer (not shown), for example a gas chromatograph, so that the analyte can be quantitatively and qualitatively determined.

For re-sampling steps 1 - 5 can then be carried out again.

Therefore, according to the present invention, it is possible to perform multiple analyzes on a single sample without losing sample solution. Thus, the needle 34, which is still filled with sample liquid after step 4, can be backwashed into the interior of the container with the aid of a syringe filled with air and then transferred again into the tight arrangement. On the other hand, similarly to the steps 1-5, rinsing operations for rinsing the syringe assembly can be performed.

Claims

claims

1. A device for removing liquids, preferably for the microliter range, comprising a container (44), a lid (50) having a bore (60) and a Aufhahmeanordnung (14) with a cannula (34) having a lateral opening (42). at the distal end, wherein the cannula (34) is sealingly but slidably removable within the bore (60) along its longitudinal axis and the lid (50) has a thickness such that the lateral opening (42) of the cannula (34) is withdrawn upon withdrawal the cannula (34) from the container (44) is received tightly in the lid (50).

2. Apparatus according to claim 1, characterized in that the receiving arrangement (14) is designed in the form of a syringe or a hose.

3. Apparatus according to claim 1 or 2, characterized in that the material of the lid (50) is PTFE.

4. Device according to one of claims 1 to 3, characterized in that the cover (50) has a main cover part (52) whose thickness x is at least twice as large, advantageously more than three times the diameter of the lateral Kanülenöffhung (42).

5. Device according to one of claims 1 to 4, characterized in that the diameter of the bore (60) corresponds at most to the outer diameter of the cannula (34).

6. Device according to one of claims 1 to 5, characterized in that the syringe assembly (14) is formed at least in two parts and a syringe body (16) which is connectable to the cannula (34).

7. The device according to claim 6, characterized in that the connection between the syringe body (16) and the cannula (34) is in the form of a screw or bayonet arrangement.

8. The device according to claim 6, characterized in that between the syringe body (16) and the cannula (34) a coupling piece (72) is provided, with which at least the syringe body (16) can be coupled in the manner of a quick coupling.

9. Apparatus according to claim 8, characterized in that the coupling piece (72, 100)

a male insert (102) detachably connectable to the syringe body (16) by means of connecting means disposed at the body end of the insert (102) and having a through bore (104) extending from the body side end of the insert to the syringe body the other end of which extends and in which a Korpuskapillare (106) for receiving a syringe channel (108) is arranged, wherein the other end locking means for locking the insert part (102) in a female Aumahmeteil (110), and

a socket-like Aumahmeteil (110) for receiving the plug-like insert part (102), wherein the receiving part (110) at its end facing away from the insert (102) end is provided with connecting means by means of which it is detachably connectable to the syringe needle (N), and wherein inside the receiving part (110) a connection capillary (112) for receiving the syringe channel (108) is arranged, which is guided at the opening end of the Aufhahmeteils (110) by means of guide means and at the other end thereof in a through hole (114), which extends inside the bush (110) from the bottom thereof to the syringe-side end of the receiving part (110), wherein the sleeve-like Aumahmeteil (110) in the region of its opening-side end inside locking means for locking with having the plug-like insert part (102).

10. snap-action coupling according to claim 9, characterized in that the plug-like insert part (102) is designed as a rotationally symmetrical component.

11. Snap-coupling according to claim 10, characterized in that the rotationally symmetrical component is offset from the coupling side and forms a cylindrical pin (116).

12. A snap coupling according to claim 11, characterized in that the pin (116) in the region of its end has a circumferential recess (118) as a latching means.

13. Snap-fit coupling according to one of claims 9 to 12, characterized in that the connecting means of the plug-like insert part (102) have a central threaded bore (120) through which the insert part (102) with a corresponding attached to the syringe body threaded attachment (122) is connectable ,

14. Snap-coupling according to claim 9, characterized in that the socket-like Aufhahmeteil (110) is designed as a rotationally symmetrical component.

15. Snap-fit coupling according to claim 9 or 14, characterized in that the latching means of the bush-like Aufhanmeteils (110) radially in the inner wall (124) of the socket part (110) are retractable.

16. A snap-action coupling according to claim 15, characterized in that the latching means retractable balls (126) which are arranged circumferentially on the inner wall (124) of the socket part (l 10).

17. A snap-action coupling according to claim 9 or 14, characterized in that the guide means for the connecting capillary (112) as a guide ring (113) formed for locking the bush-like insert part (102) in the direction of the longitudinal axis of the bush-like Aufhahmeteils (110) exposing the Locking means is displaceable.

18. A snap-action coupling according to claim 9 or 14, characterized in that the connecting means of the bush-like insert part (102) have a threaded pin (128).

19. Device according to one of the preceding claims, characterized in that it additionally comprises a mechanical protection against complete withdrawal of the cannula (34) from the bore (60) of the lid (50).