EP2606977A1 - Pipette tips - Google Patents

Abstract

The tip (1) has a seat section provided next to an upper opening (6) at an inner periphery. The seat section includes a holding region with radial inward projecting part, axially extending ribs and a sealing region that is formed below the holding region. The sealing region is formed, so that the tip is held and sealed on a neck, during insertion of the tip with the seat section on the neck by fitting force. The ribs are plastically deformed, and an elastic deformation occurs on an outer side of the ribs in the seat section.

Description

The invention relates to a pipette tip.

Pipette tips are used with pipettes and other dosing devices to dose liquids. In the following, pipettes and metering devices are collectively referred to as "pipetting device". Pipette tips have an elongate, tubular body having a pipetting opening at the lower end and an attachment opening for clamping onto a lip of a pipetting device at the upper end. Known are standardized conical approaches with a standard geometry, which is used by many manufacturers uniformly and which is characterized for each pipette tip size by a specific average diameter and by a specific cone angle of the conical approach. Also known are approaches that have two circumferential rings or beads that can be rigid or designed as elastic sealing rings. These approaches are used in dosing machines in particular. They are often dimensioned so that pipette tips can be clamped on them, which are dimensioned for clamping on the standardized conical approaches.

The pipetting device comprises a gas displacement device, which is usually a piston with a cylinder axially displaceable therein. The gas displacement device is connected to a through hole of the neck. The pipette tip is clamped by pressing the approach of the pipette into the upper opening of the pipette tip sealingly on the approach.

By means of the gas displacement device, an air column is displaced to suck liquid into the seated on the approach pipette tip or ejected from this. If the air column is displaced away from the pipette tip, it will a certain amount of liquid is sucked through the lower opening in the pipette tip. By moving the air column toward the pipette tip, an amount of liquid is released through the lower opening from the pipette tip.

Pipetting devices usually have an ejector, which acts on the upper edge of the pipette tip to squeeze them from the approach. This avoids the user having to touch the contaminated pipette tip to pull it off the neck.

The pipetting device may be a handheld pipette that the user can hold and manipulate with one hand. The pipetting device can also be a dosing station or integrated into a workstation. In all cases, the gas displacement device may be manual or motorized. The plugging and dropping of the pipette tip can also be done manually or motor driven.

To avoid incorrect pipetting, the pipette tip must be sealingly fixed on the shoulder. In addition, the forces for attaching and dropping the pipette tip from the neck should not be too high. In conventional pipette tips, the contact area between the pipette tip and the conical shoulder is frusto-conical. When attaching the pipette tip, the pipette tip is stretched elastically on the circumference by the approach. The spring characteristic is steep, so high Aufsteckkräfte are applied. After fitting, a correspondingly high static friction acts between the attachment and the pipette tip. This static friction must be overcome when the pipette tip is dropped. The user is burdened by the high forces for attaching and dropping the pipette tip. As far as the plugging and dropping By means of motor drives, these must be correspondingly powerful and have a high power consumption.

The US 6,197,259 B1 describes a pipette tip that can be easily and firmly mounted on a neck of a pipette and easily dropped from it by the use of relatively small axial pinning and ejection forces of six and three pounds (26.7N and 13.3N, respectively). The pipette tip has a tubular pipette section which has a conical upper end with an inner diameter at its upper end that is larger than the diameter of the lip of the pipette onto which the pipette tip is to be mounted. Further, the pipette tip has a hollow central portion and an annular sealing portion at the junction between the upper end and the central portion. The annular sealing area has an inner diameter that is smaller than a value "x" and is designed to engage the lower end of a seal zone of the lug so as to be stretched radially outward when the lug is inserted, whereby a liquid-tight seal between the sealing zone of the neck and the sealing area of the pipette tip is generated. Further, the pipette tip on the inside adjacent to the sealing region has lateral stabilizing means which engage the outer surface of the neck to stabilize the pipette tip on the neck. These lateral stabilizing means comprise at least three circumferentially spaced contacts extending inwardly from the inner surface of the pipette tip. The diametrical spacing of the contacts is sized to easily engage the free end of the lug and allow the lower end of the lug to pass without flaring the side walls of the pipette tip on which the contacts are located. The contacts provide lateral support of the pipette tip on the neck to prevent the pipette tip from lateral movement when lateral outward Forces acting on the pipette tip, such as the removal of liquid on a wall. As the lower end of the seal zone of the lug engages the seal area of the pipette tip, the pipette tip is stretched in the seal area and immediately adjacent thereto. As the contacts guide the tip onto the lug and align it stably and securely on the lug, the side wall of the pipette tip carrying the contacts deforms inward and does not expand, thereby applying minimal force to the lug upon insertion.

The US 7,339,373 B1 describes an ergonomically designed pipette tip which can be securely attached to a shaft of a pipette, while at the same time the axial force required for attachment and ejection is considerably reduced. The ergonomic pipette tip includes injected, thin expansion joints flanked by thicker wall segments and / or a second resilient material to reduce the force required to stretch the top edge of the pipette tip as the pipette stem enters the sealing region of the pipette tip is introduced. In addition, the pipette tip has on its inside one or more projections which are intended to limit the insertion depth of the pipette shaft into the pipette tip as a stopper.

The EP 1 520 624 B1 describes a pipette tip made of plastic with an elongated, tubular body having a pipetting opening at a lower end and at an upper end an insertion opening for attachment to a receiving shaft of a pipetting device. The pipette tip has near the upper end a circumferential curve along a closed curve, in different circumferential positions different distances from the lower end on the web. The circumferential ridge has a contact area on the inside, which revolves on a surface of revolution. More bridges extend from the maximum of the lower end remote locations of the circumferential ridge to the upper end. The pipette tip comes with the contact area on the inside of the circumferential ridge in sealing contact with the neck of a pipetting device. Upon ejection, the ejector of the pipetting device presses against the further webs at the upper end of the pipette tip. By the other webs the ejection force is transmitted to the maximum remote from the lower end points of the circumferential ridge. As a result, these points of the circumferential ridge are pressed slightly towards the lower end. Based on a plane perpendicular to the tubular body of the pipette tip level, the circumferential ridge is pressed slightly flatter. The further webs forms a stiff region, which is subjected to only a relatively small deformation upon transmission of forces. Since the circumferential web is aligned transversely to the other webs, it is relatively easily deformed by the forces introduced in the direction of the further web. As a result, the circumferential ridge widens slightly and accordingly the static friction between the inside of the circumferential ridge or the contact area and the neck is reduced. Thus, the forces required to disengage the pipette tip from the receiving shaft are reduced. In addition, the pipette tip is more flexible in the area of the circumferential web, so that the forces for plugging are reduced to one approach and the attachment to receiving shafts with different dimensions is favored.

In the case of the pipette tips from the above documents, dimensional fluctuations of the pipette tip and of the projection are compensated by elastic stretching of the pipette tip. If the inside diameter of the pipette tip in the seating area falls well short of the nominal size or the outside diameter of the projection greatly exceeds the nominal size, higher attachment forces and ejection forces result.

Based on this, the object of the invention is to provide a pipette tip in which the required ejection force for ejecting the pipette tip from the attachment of a pipetting device is reduced and dimensional tolerances have a smaller influence on the ejection force.
The object is achieved by a pipette tip having the features of claim 1. Advantageous embodiments of the pipette tip are specified in subclaims.

The pipette tip according to the invention is in the form of an elongate tube having a lower opening at the lower end for the passage of liquid and an upper opening at the upper end, wherein adjacent to the upper opening at the inner periphery there is a seating area which is adapted for attachment to a standardized serves the conical approach of a pipetting device, wherein the seating area has a holding portion with radially inwardly projecting, axially extending ribs and below the holding portion has a sealing region and is formed so that when attaching the pipette tip with the seating area on the approach with a Aufsteckkraft, a holding and sealing the pipette tip on the approach ensures that the ribs are partially plastically deformed and outside of the ribs in the seating area enters an elastic deformation.

When attaching the pipette tip according to the invention to a standardized conical projection of a pipetting device, the surface pressure in the region of the axial ribs causes a partial plastic deformation of the axial ribs. Furthermore, the pipette tip is elastically deformed in the seating area outside the axial ribs. A portion of the Aufsteckkraft is consumed for the plastic deformation of the ribs and another part of the Aufsteckkraft is stored in the elastic deformation. As a result, the pipette tip is held under tension on the approach. The ribs support the pipette tip laterally so that it does not wobble under the influence of lateral forces. To eject the pipette tip, only the force stored by the elastic deformation has to be overcome. The attributable to the plastic deformation of the axial ribs part of Aufsteckkraft does not need to be overcome again as a stored force when ejecting the pipette tip. The ejection force must overcome the frictional force that exists due to the elastic bias between the pipette tip and the neck. Dimensional tolerances of the pipette tip and neck are compensated for by the plastic deformation of the ribs and have less effect on the elastic deformation in the seating area than in conventional pipette tips. As a result, the influence of dimensional tolerances on the ejection force is reduced.

For ejecting the pipette tip of the approach according to the invention thus only a small ejection force is applied. This relieves the user of a hand-held pipette with an ejector, which is to be operated by means of the thumb. The user can easily apply the required attachment force by means of his forearm and hand. Likewise, motor-driven ejectors are relieved by the pipette tip according to the invention.

The elastic deformation in the seating area can take place in the sealing area and / or in the holding area between the ribs. The elastic deformation may be restricted to the sealing area or to the area between the ribs, or may take place both in the sealing area and in the area between the ribs. The plastic deformation of the ribs and the elastic deformation in the seating area is determined by the geometry of the seating area and the material of the pipette tip. The plastic deformation of the ribs is determined in particular by the rib profile. The wall thickness of the pipette tip in the area of the ribs determines the degree of elastic deformation in this area. The wall thickness in the region of the ribs can be chosen so large that the pipette tip behaves rigidly there and only a plastic deformation occurs at the ribs. An elastic or plastic deformation in the sealing region can be determined, in particular, by the wall thickness of the pipette tip in the sealing region and, if necessary, by the geometry of a sealing projection running around the inside of the sealing region.

The standardized conical approaches are defined for each pipette tip size by a particular median diameter and cone angle. This is summarized in the table below: Pipette tip size (in microliters) Average diameter (in mm) Cone angle (in degrees) 0.1 -10 2.95 4.77 0.1 - 20 2.95 4.77 0,5 - 20 3.3 6.68 2 - 20 4.4 6.99 20 - 30 4.4 6.99 50 - 1000 7.1 2.71 50 - 1250 7.1 2.48 500 - 2500 9.3 3.78 100 - 5000 12.4 4.00 1000 - 10 000 14.3 4.35 1000 - 10 000 14.3 4.35

For the diameter data, a tolerance of +/- 0.05 mm applies and for the angle specifications a tolerance of +/- 0.3 °.

According to one embodiment, the ribs are distributed uniformly over the circumference. This promotes uniform deformation and support of the pipette tip in the seating area.

According to a further embodiment, the pipette tip has three to twelve ribs, preferably five to seven ribs, furthermore preferably six ribs. As a result, a uniform support is achieved. The mentioned numbers of ribs favor plastically deformable ribs with dimensions that are easy to manufacture.

According to another embodiment, the ribs are dimensioned so that their Maßüberlappung with the standardized conical approach relative to the position taken by the approach when the pipette tip is attached with a Aufsteckkraft on the approach, the holding and sealing of the pipette tip on the Guaranteed approach, at least 0.1 mm, preferably at least 0.2 mm and / or at most 0.5 mm, preferably at most 0.3 mm. This dimensional overlap favors a partial plastic deformation of the ribs.

According to a further embodiment, the pipette tip next to the upper opening has inwardly projecting, axially extended further ribs, which extend less far radially inwardly than the ribs, wherein the further ribs are each arranged between two ribs. The further ribs can serve to guide the pipette tip in addition to the approach, wherein the further ribs when plugging the pipette tip can be subjected to the approach no deformation or only a smaller deformation than the ribs. According to a preferred embodiment, the further ribs are dimensioned so that they are not deformed when the pipette tip with a Aufsteckkraft on the Attached approach that ensures holding and sealing the pipette tip on the approach.

According to a further embodiment, the ribs and / or the further ribs have a radially inwardly tapering profile. This promotes plastic deformation of the axial ribs at the inner end of the profile. According to a further embodiment, the ribs and / or the further ribs have a triangular or a trapezoidal or a parabolic profile. According to a further embodiment, the ribs have a profile with a structured surface, e.g. a profile formed by nubs, pins or needles or occupied therewith.

According to a preferred embodiment, the pipette tip on the outside on the periphery of the ribs and / or the other ribs overlapping profiling. The profiles are used, for example, the stiffening of the pipette tip in the rib area or the marking of the pipette tip. If they serve to identify the pipette tip, the arrangement of the profilings over the ribs and / or the further ribs promotes the recognizability of the profilings on a transparent pipette tip. Otherwise, the ribs and / or the other ribs could be perceived as profilings.

According to a further embodiment, the pipette tip expands in the region in which the ribs are arranged, and / or conically in the sealing region towards the upper opening. As a result, the onset of the approach of a pipetting device is favored. In principle, the regions mentioned may have a circular cylindrical shape instead of a conical if the ribs are adapted by plastic deformation to the standardized conical approach and in the sealing area circumferential sealing projection is present, with which the sealing area abuts the approach.

According to a further embodiment, the sealing region has an inwardly extending on the circumference, inwardly projecting sealing projection. The sealing projection is for example a sealing bead or a sealing lip.

According to a further embodiment, the pipette tip in the region in which the ribs are arranged has a wall thickness which is greater than its wall thickness in the sealing region. As a result, the pipette tip in the region of the axial ribs is stiffer, whereby the plastic deformation of the ribs is favored.

According to a further embodiment, the pipette tip has means for limiting the attachment to the standardized conical projection, which stop the attachment to the approach when a Aufsteckkraft is reached, the holding and sealing the pipette tip on the neck and a partial plastic deformation of the Ribs guaranteed. As a result, the plastic deformation of the axial ribs can be limited to a suitable degree. The means for limiting may be formed by a stop which may be formed by one or more projections which project inwardly from the inner circumference of the pipette tip.

According to a further embodiment, the means for limiting the Aufsteckens a under the sealing area conically widening towards the upper opening towards the brake area. When fitting on the standardized conical approach, the lower edge of the approach meets the brake area and the insertion of the approach is by the taper of the braking area gradually stopped. As a result, the user is less stressed than in a conventional stop, which stops the Aufsteckbewegung abruptly.

Preferably, the pipette tip is made of a plastic. Further preferably, the pipette tip is made of a polyolefin, preferably polypropylene or polyethylene. According to a further embodiment, the pipette tip is translucent, preferably transparent. Further preferably, the pipette tip is made by injection molding. Preferably, the inner and / or outer diameter of the pipette tip increases from the lower opening to the upper opening.

Fig. 1a-e

eine Pipettenspitze mit axialen Rippen und umlaufendem Dichtvorsprung in Seitenansicht (Fig. 1a), in einem Längsschnitt (Fig. 1b), in vergrößerter Unteransicht (Fig. 1c), in vergrößerter Draufsicht (Fig. 1d) und in einer Perspektivansicht mit Ausbruch (Fig. 1e);

Fig. 2

eine Pipette mit Ansatz beim Aufstecken der Pipettenspitze von Fig. 1 in Seitenansicht;

Fig. 3

der Ansatz eingesetzt in den Sitzbereich der Pipettenspitze von Fig. 1 in einem teilweisen Längsschnitt;

Fig. 4

ein Vergleich der Aufsteck- und Abwurfkräfte der erfindungsgemäßen Pipettenspitze (Fig. 4a) und bei herkömmlichen Pipettenspitzen (Fig. 4b);

Fig. 5 a, b

mittlerer Durchmesser und Konuswinkel standardisierter konischer Ansätze zum Aufstecken von Pipettenspitzen verschiedener Größen in einer Übersicht.

The invention will be explained in more detail with reference to the accompanying drawings of an embodiment. In the drawings show:

Fig. 1a-e

a pipette tip with axial ribs and circumferential sealing projection in side view ( Fig. 1a ), in a longitudinal section ( Fig. 1b ), in an enlarged bottom view ( Fig. 1c ), in enlarged plan view ( Fig. 1d ) and in a perspective view with outbreak ( Fig. 1e );

Fig. 2

a pipette with approach when attaching the pipette tip of Fig. 1 in side view;

Fig. 3

The approach used in the seating area of the pipette tip of Fig. 1 in a partial longitudinal section;

Fig. 4

a comparison of the Aufsteck- and discharge forces of the pipette tip according to the invention ( Fig. 4a ) and in conventional pipette tips ( Fig. 4b );

Fig. 5 a, b

average diameter and cone angle of standardized conical approaches for attaching pipette tips of various sizes in an overview.

In the present application, the terms "top" and "bottom" refer to the orientation of a pipette tip during pipetting in which the pipette tip is vertically aligned and the bottom opening is at the bottom and the top opening is at the top.

In the following description of various embodiments, matching features are designated by the same reference numerals.

According to Fig. 1 For example, a pipette tip 1 has an elongate, tubular body 2 which has a lower opening 4 at the lower end 3 and an attachment opening 6 at the upper end 5. The lower opening 4 is smaller than the upper opening 6.

Generally, the inner and / or outer diameter of the tubular body 2 increases from the lower opening 4 toward the upper opening 6. In the example, the tubular body 2 below a conical initial section 7, about a less conical central portion 8 and above a head portion 9. A pipette tip 1 according to the invention can also extend in other ways from the lower opening 4 to the upper opening 6, especially in sections or steadily.

The head portion 9 has, immediately adjacent to the upper opening 6, an enlarged diameter insertion area 10 that extends only over a short portion of the head portion 9. Below the insertion region 10, a holding region 11 adjoins, in the ribs 12, 13 protrude inwardly from the inner periphery of the head portion. These are axially extending ribs 12 which project further radially inwardly and further axially extending ribs 13 which project less inwardly. In Fig. 1d and e is clear to see that the Ribs 12 project further from the inner periphery of the pipette tip 1 as the other ribs 13. In the example, six ribs 12 and six further ribs 13 are present. Between each two ribs 12 each have a further rib 13 is arranged.

Above the ribs 12 and the other ribs 13 next to the insertion region 10 each have a short bevel 14, 15th

The head portion 9 has at the top an outwardly projecting frusto-conical portion 16. This is bounded below by an outer step 17. Inside, the head portion has an inner step 18. The ribs 12 and the further ribs 13 extend beyond the inner step 18. Below they end in a sealing region 19. There is inside of the circumference of the head portion 9 before a circumferential sealing projection 20 in the form of a bead. The ribs 12 and the further ribs 13 extend up to the sealing projection 20. In the region of the inner step 18, the further ribs 13 have a discontinuity 21.

The ribs 12 and the further ribs 13 have a parabolic profile 22, 23 in the region above the inner step 18. The profile has a flattening or a flat radius 24, 25 at the furthest inwardly projecting region. In the direction from top to bottom, first the parabolic profile 22, 23 widens to a point 26, 27 of maximum width, from where it becomes narrower again up to the inner step 18.

Furthermore, the head area outside the circumference of the frusto-conical region 16 has teardrop-shaped, outwardly projecting profiles 28. The edges of the profiles 28 coincide with the edges of the ribs 12 and the further ribs 13 above the inner step 18th

Below the sealing projection 20, a conical braking region 29 connects to the sealing region 19, which tapers downwards or widens upwards.

In the region of the ribs 12, 13, the head section 9 is slightly conical inside above the inner step 18 and below the inner step 18 and in the sealing region 19. In the braking area 29, it is more conical.

The area of the further ribs 13, the sealing area 19 and the braking area 29 are collectively referred to as "seating area" 30.

Below the braking area 29, the middle section 8 limits the body 2.

According to Fig. 2 a manual pipette 31 has a housing 32 in the form of a handle, which contains a displacement device 33 for displacing air and to which an actuating element 34 for actuating the displacement device 33 and an ejector 35 with an associated further actuating element 36 are arranged. At the bottom, a standardized conical projection 37 is arranged on the housing 32.

A pipette tip 1 is attachable to the neck 37.

According to Fig. 3 When plugging the pipette tip 1 with the seating area 30 on the standardized conical projection 37, the ribs 12 are partially plastically deformed. This is in Fig. 3 in the overlap region of the contours of the projection 37 and the ribs 12 given. Between the ribs 12 and the further ribs 13, the wall of the pipette tip 1 is slightly elastically deformed. In the region of the sealing projection 20 of the seating area 30 is elastically deformed by the wall slightly outwardly with respect to the position shown is deflected, in which the contours of the sealing projection 20 and the projection 37 overlap each other.

In the region of the lower end 38 of the neck 37 (in Fig. 3 left), the brake area 29 is plastically deformed. This is where the contours of the lower extension end 38 and the braking region 29 overlap.

According to Fig. 4a Part of the Aufsteckkraft for the plastic deformation of the pipette tip is needed. Another part of the Aufsteckkraft accounts for the elastic part of the deformation of the pipette tip 1. Thus, a part of the Aufsteckkraft is irreversibly consumed for the plastic deformation of the pipette tip 1. The ejection force required for ejecting the pipette tip 1 from the approach only has to overcome the part of the insertion force attributable to the elastic deformation of the pipette tip 1.

Thus, in the case of the pipette tip 1 according to the invention, the ejection force is lower than in the case of a conventional pipette tip, which is exclusively elastically deformed by the attachment force. In conventional pipette tips Aufsteckkraft and ejection force match when the pipette tip is attached with little physical effort. This is in Fig. 4b shown. In the upper force range, ie when the user spends a great deal of force, ie, the pipette literally "rams" into the conventional pipette tip, the release force is even greater than the attachment force.

Fig. 5 a . b shows, respectively, the mean diameter and the cone angle of a standardized conical projection 37 over an associated pipette tip 1 with a certain tip size. The mean diameter is given in millimeters and the cone angle in degrees. As a measure of the pipette tip size is respectively the area of the filling volume in microliter or milliliter specified, with the pipette tip 1 is filled. The median diameter of the lug 37 refers to a diameter between the lower and upper ends of the lug 37. It need not necessarily be a diameter located exactly midway between the lower and upper ends of the lug. However, the average diameter may also fall exactly in the middle between the lower end and the upper end of the neck.

Additionally are in Fig. 5 a . b the tolerances are given for the mean diameter (+/- 0.05mm) and for the angle data (+/- 0.3 °). The lugs 37 are manufactured with appropriate tolerances.

LIST OF REFERENCE NUMBERS

1

pipette tip

2

tubular body

3

lower end

4

lower opening

5

top end

6

upper opening

7

conical beginning section

8th

conical middle section

9

header

10

insertion

11

holding area

12

ribs

13

more ribs

14

short bevel

15

another short chamfer

16

frusto-conical area

17

outer stage

18

inner stage

19

sealing area

20

sealing projection

21

discontinuity

22

parabolic profile

23

another parabolic profile

24

radius

25

radius

26

Position of maximum width

27

Position of maximum width

28

drop-shaped profiles

29

conical braking area

30

sitting area

31

hand pipette

32

casing

33

displacement device

34

actuator

35

ejector

36

another actuator

37

conical approach

38

lower end of approach

Claims (15)

Pipette tip having the shape of an elongated tube with a lower opening (4) at the lower end (3) for the passage of liquid and an upper opening (6) at the upper end, adjacent to the inner periphery of the upper opening (6) Seating area (30) is provided for attachment to a standardized conical projection (37) of a pipetting device (31), wherein the seating area (30) has a holding portion (11) with radially inwardly projecting, axially extending ribs (12) and below of the holding region (11) has a sealing region (19) and is designed so that when attaching the pipette tip (1) with the seating area (30) on the projection (37) with a Aufsteckkraft that holding and sealing the pipette tip (1) on the projection (37) ensures that the ribs (12) are partially plastically deformed and outside of the ribs (12) in the seating area (30) enters an elastic deformation. A pipette tip according to claim 1, wherein the ribs (12) are uniformly distributed around the circumference. A pipette tip according to claim 1 or 2, comprising three to 12 ribs (12), preferably five to seven ribs, further preferably six ribs. A pipette tip according to any one of claims 1 to 3, wherein the ribs (12) are dimensioned such that their dimension overlap with the standardized conical projection (37) relative to the position occupied by the projection (37) when the pipette tip (1) with a Aufsteckkraft on the approach (37) is attached, the holding and sealing the pipette tip (1) on the neck (37) ensures at least 0.1 mm, preferably at least 0.2 mm and / or at most 0.5 mm, preferably at most 0.3 mm. A pipette tip according to any one of claims 1 to 4, further comprising inwardly projecting, axially extending further ribs (13) inwardly adjacent the upper opening (6) which extend less inwardly radially than the ribs, the further ribs respectively between two ribs are arranged. A pipette tip according to claim 5, wherein the further ribs (13) are dimensioned so that they are not deformed when the pipette tip (1) is attached with a Aufsteckkraft on the projection (37), the holding and sealing of the pipette tip (1 ) on the neck (37). A pipette tip according to any one of claims 1 to 6, wherein the ribs (12) and / or the further ribs (13) have a radially inwardly tapering profile. A pipette tip according to claim 7, wherein the ribs (12) and / or the further ribs (13) have a triangular or a trapezoidal or a parabolic profile. Pipette tip according to one of claims 1 to 8, the outside of the circumference of the ribs (12) and / or the further ribs (13) overlapping profilings (28). A pipette tip according to any one of claims 1 to 9, which widens conically in the region in which the ribs (12) are arranged and / or in the sealing region (19) towards the upper opening. Pipette tip according to one of claims 1 to 10, which in the sealing region (19) has a circumferentially encircling, inwardly projecting sealing projection (20). Pipette tip according to one of claims 1 to 11, which in the holding region (11) has a wall thickness which is greater than its wall thickness in the sealing region (19). A pipette tip according to any one of claims 1 to 12, including means (29) for pinching the standardized conical lug (37) which stop plugging onto the lug (37) when an attachment force is achieved, holding and holding Sealing the pipette tip (1) on the projection (37) and a partial plastic deformation of the ribs (12) guaranteed. A pipette tip according to claim 13, wherein the means for limiting (29) clogging is a braking region (29) flared under the sealing region (19) in a conical manner towards the upper opening. Pipette tip according to one of claims 1 to 14, which is made of plastic, preferably of a polyolefin, further preferably made of polypropylene or polyethylene.

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