Abstract: A hybrid manual-electronic pipette combines a manually driven piston with real-time electronic measurement of liquid volume and piston displacement while compensating for both pipette-specific and pipette model-specific variations. The hybrid nature of the pipette facilitates increased accuracy and improved ease of use, and enables additional functionalities not practicable with traditional manual pipettes.

Abstract: A system including an inspection chip equipped with at least a pump connection having a flow path opening for interconnecting to a micro-pump, a flow path through which a fluid flows, and a fluid mixing section for joining and mixing two or more fluids, and including a system body equipped with at least a base body, a chip connection having a flow path opening for interconnecting to the inspection chip, a micro-pump unit in the base body including micro-pumps in substantially the same shape, a detection processor and a controller for controlling at least the functions of the micro-pump unit and the detection processor, and the joining amount ratio is adjusted to set the mixing ratio of two fluids to be joined in the fluid mixing section to be approximately m:n (not 1:1) by making the drive voltages of the micro-pumps substantially equal to each other.

Abstract: A hybrid manual-electronic pipette combines a manually driven piston with real-time electronic measurement of liquid volume and piston displacement while compensating for both pipette-specific and pipette model-specific variations. The hybrid nature of the pipette facilitates increased accuracy and improved ease of use, and enables additional functionalities not practicable with traditional manual pipettes.

Abstract: A positive displacement type substance sampling and dispensing device comprises a central plunger formed from a first material. A plunger housing is formed from a second material having a melting point lower than the first material, the housing being formed by molding and setting the second material on to the surface of the plunger so that the plunger can slide in the housing to draw a substance into it.

Abstract: The invention relates to a pipette, comprising a tip remover element which, upon moving it against a tip, disengages the tip. The remover element is operated with a mechanism, comprising a rotatable ramp member which is provided with a circle-forming ramp surface, including one or more segments within which the ramp surface has a high point and a low point, whereby the ramp surface, upon rotating through a single segment, forces the remover element first to move against the tip and then allows it to return.

Abstract: A multivolume pipette is provided. In an exemplary embodiment, the multivolume pipette includes a pipette body, a piston disposed within the pipette body, a first chamber, a second chamber, and a valve. The first chamber and the second chamber are defined at least in part by an inner wall of the pipette body and the piston. The valve is capable of placing the second chamber in fluid communication with an external environment to provide a first volume range of the multivolume pipette. The valve is also capable of placing the second chamber in fluid communication with the first chamber to provide a second volume range of the multivolume pipette.

Abstract: Pipetting device for metering liquids comprising a piston actuating rod, at least one receiver for a piston head arranged on one end of the piston actuating rod and which is defined by an abutment surface for the piston head in the axial direction of the piston actuating rod, and comprises a through-opening for a piston rod opposing said piston head and a base for supporting the piston head surrounding the through-opening, at least one cylinder with a hollow space, at least one seat for holding a pipette tip, at least one through-channel connecting the hollow space of a cylinder to a through-hole in a seat and at least one piston arranged longitudinally displaceably in a cylinder with a piston rod extending through the through-opening of a receiver and a piston head at the end of the piston rod arranged in the receiver, which is positioned on the base with a lower face facing the piston rod and comprises a resilient body projecting beyond the upper face facing away from the piston rod, which does not bear aga

Abstract: The present invention provides systems for isolating toxins and collecting an eluate from a sampling column for subsequent testing and to methods of extracting and collecting an eluate using the same systems. Preferably, the systems comprise a sample holder such as an immuno-affinity column for holding the sample and a self-contained fluid delivery system that can deliver liquid, e.g., reagents, and gaseous fluids, e.g., compressed air. More preferably, the fluid control system of the fluid delivery system provides some amount of pressurized gas continuously to the headspace of the column even when a fluid is not being forced through the resin gel in the column.

Abstract: The invention relates to an electric pipette (1) comprising a body (2), a tip part (4), a hook part (5), a push-button part (6) and a display part (7), said body (1) having a vertical axis (3) and at least one of the parts selected from the group consisting of the hook part (5), the push-button part (6) and the display part (7) is rotatable about the vertical axis (3) of the electric pipette (1) correspondingly by an angle ?1, ?2 or ?3.

Abstract: A liquid sealed air displacement apparatus may be used in a fluid transfer device to transfer volumes of fluid. The air displacement apparatus may include a piston and a cylinder defining a displacement chamber for receiving the piston. The air displacement apparatus may be used to displace precise volumes of air into the air displacement chamber. Displacing the air creates a negative pressure in the air displacement chamber (i.e., suction), which may cause a precise volume of fluid to be drawn into the fluid transfer device. The piston and the cylinder may define a diametrical clearance for receiving sealing fluid, which may prevent air leakage and wear.

Abstract: The invention relates to a controllable pipette comprising a piston actuated by a motor, a control system allowing actuation of the piston according to a given pipetting function consisting of several steps, setting keys (7, 8) for selecting the desired pipetting function, a switch (1), which activates the function steps when depressed, and a display (3). The control system comprises a change function, whose activation enables a change of the selected function in the process of its operation. When the change function can be activated, this is indicated on the display and it can be activated by depressing a given setting key.

Abstract: This invention relates to a method for selecting a plunger-cylinder tip of a pipette and a device for carrying out the method. In the method, the dose size is entered into the control electronics of the pipetting device; the dose size is stored in the control electronics; the amount of doses is entered; and on the basis of the dose size and the amount of doses, the control electronics indicates suitable available interchangeable components on the display.

Abstract: A liquid aspiration method which includes a method for determining the quality of the aspirated sample through mathematical analysis of the standard deviation of the residuals of the linear regression analysis of the aspiration pressure profile generated between the onset of actual aspiration and the end of actual aspiration and comparison of the results with predetermined known values.

Abstract: A micro-cassette 1 stores a sample, a reagent, and an additive, and comprises a sensor measures the component of measurement item. Analysis device 2 comprises liquid control unit controls each liquid in micro-cassette 1. Mixing controller 33 mixes the sample and the additive sent to sample processing unit 13, and generates the first sample includes a formed element. Isolation unit 14 generates the second sample from the first sample sent from sample processing unit 13. Sensor 18 measures the compound liquid of the second sample and reagent, and generates the analysis signal.

Abstract: A hybrid manual-electronic pipette combines a manually driven piston with real-time electronic measurement of liquid volume and piston displacement while compensating for both pipette-specific and pipette model-specific variations. The hybrid nature of the pipette facilitates increased accuracy and improved ease of use, and enables additional functionalities not practicable with traditional manual pipettes.

Abstract: A dispensing system delivers a precise amount of fluid for biological or chemical processing and/or analysis. Dispensing means moves the fluid. The dispensing means is operated by a pneumatic force. Connection means delivers the fluid to the desired location. An actuator means provides the pneumatic force to the dispensing means. Valving means transmits the pneumatic force from the actuator means to the dispensing means.

Abstract: A multichannel pipette, including a grip part defining a longitudinal axis and including a piston-driving device movable axially thereon, a displacement part rotating about the axis and having cylinder and piston arrangements, and a connection device for detachably connecting the grip part to the displacement part and permitting a rotation of the displacement about the longitudinal axis. The connection device includes threaded connection elements engaged with one another. The pistons move axially to the cylinders via a piston-driving device. A connection part of the threaded elements is axially connected with the cylinders and includes a clearance for a rotary bearing provided therein. Form-fit configurations on the support and connection parts are engaged to prevent a reverse rotation of the connection part relative to the support part. By a manual release action, the form-fit configurations disengage, such that the connection part rotates in a reverse rotation relative to the support part.

Abstract: This invention provides improved components (e.g. array “pins”, print head, substrate platen, print head platen, and the like) for microarray printing devices as well as microarray printing devices incorporating such components. In one embodiment, this invention provides a microarray print head comprising a plurality of glass or quartz spotting capillaries disposed in a support that maintains a fixed spacing between the spotting capillaries and that permits the spotting capillaries to move in a direction parallel to the long axis of the capillaries.

Abstract: A fluid dispenser useful in methods and apparatuses for automated biological reaction systems including a barrel, a coupler, a piston associated with the barrel, and a sealing surface that seals the inner diameter against fluid flow at the lower extent of the piston.

Abstract: The hand-held pipette comprises at least one track having increments, at least one brush, and a register area arranged to come into contact with each brush after it has traveled a predetermined number of increments.

Abstract: An electronic metering apparatus for metering liquids, with a longitudinal, handleable housing, a drive, arranged in the housing, with an electric motor, at least one displacer device, arranged in the housing or being capable to be arranged on the same, with a displacer element, which is connected to the drive and/or connectable to the same, at least one holding device on the bottom end of the housing for holding a pipette point or a syringe, at least one electric operational control in or on the housing, at least one electric information device in or on the housing, an electric control unit arranged in the housing, which is connected to the electric motor, the electric operational control and the electric information device, and which controls the information device depending on the position and/or previous changes of the position of the displacer element, in order to put out an information concerning the next reasonable dislocation of the displacer element, and an electric power supply.

Abstract: Pipetting device for metering liquids comprising a piston actuating rod, at least one receiver for a piston head arranged on one end of the piston actuating rod and which is defined by an abutment surface for the piston head in the axial direction of the piston actuating rod, and comprises a through-opening for a piston rod opposing said piston head and a base for supporting the piston head surrounding the through-opening, at least one cylinder with a hollow space, at least one seat for holding a pipette tip, at least one through-channel connecting the hollow space of a cylinder to a through-hole in a seat and at least one piston arranged longitudinally displaceably in a cylinder with a piston rod extending through the through-opening of a receiver and a piston head at the end of the piston rod arranged in the receiver, which is positioned on the base with a lower face facing the piston rod and comprises a resilient body projecting beyond the upper face facing away from the piston rod, which does not bear aga

Abstract: In a preferred embodiment, a pipettor head, including: a body; one or more solenoid valves disposed in the body; each one or more solenoid valves having an outlet at a lower end and an inlet at an upper end; each one or more solenoid valves having an outlet attached to a dispensing passageway; each one or more solenoid valves having its inlet attached to a standpipe; and the standpipe having an open top communicating with an interior of a closed vacuum/pressure chamber defined in the pipettor head, the closed vacuum/pressure chamber being arranged such that vacuum or pressure may be selectively applied to the closed vacuum/pressure chamber. A method of using the pipettor head is also provided.

Abstract: An air-filled pipette for accurately metering small and large volumes of fluid samples is provided. The pipette has dual resolution capability such that the pipette can accurately aspirate a wide range of sample volumes and deliver them contact-free (touchless). The pipette may include an extension mandrel that reduces air space in a disposable tip within the pipette. The dual resolution capability and/or the extension mandrel also minimize errors associated with the compressibility of air. Multiple pipettes may also be arranged to form a pipetting module for the metering of multiple sample volumes simultaneously and automatically. The pipette includes a channel block having at least one cylindrical passage, that slides up and down over a rod, and a cylinder, with an axially extending passage therethrough, that is sized, shaped and aligned to fit into the cylindrical passage in a dynamic sealing relationship. A method for mixing multiple fluid samples within a pipette tip is also provided.

Abstract: A transfer unit for transferring members such as reaction vessels having an upper end opening or dispensing tips or the like includes at least one arm pivotally movable about a shaft and a holder mounted on the arm for detachably supporting the member to be transferred. The holder is provided with a rod portion having a distal end adapted to be fitted in the upper end opening of the member to be transferred, a rod holding portion slidably and elastically supporting the rod portion and a guide portion surrounding the rod portion thereabout and sliding along the axis of the rod portion to release the fitting of the member from the distal end of the rod portion. The guide portion is formed with at least two elongated apertures extending in parallel with the axis of the rod portion, and the rod portion is provided with protrusions fixed thereto and extending through the elongated apertures to regulate the movement of the guide portion.

Abstract: A sample preparation system provides an automated process that dispenses appropriate amounts of solid material into wells of a microtiter plate for mixing into a suspension. The system utilizes an array of hollow tubes that are lowered into a particle reservoir such that particle material is forced up into the tubes. During loading, solid plungers in the tubes are positioned a known distance from the open end of the tubes. When the particle material is to be dispensed, the plungers are lowered to push the particle material out of the tubes and into receiving wells of the microtiter plate. The plunger stroke and internal diameter of the tubes defines the dispensed volume of particle material.

Abstract: A pipette includes a housing defining a suction chamber. A piston is configured to move in the suction chamber. A first retainer mechanism includes a first threading configured to limit a motion of the piston in the suction chamber. A second retainer mechanism includes a second threading configured to limit the motion of the piston in the suction chamber, the second threading having a pitch less than a pitch of the first threading.

Abstract: A pipette control arrangement consists of a housing assembly adapted for operatively housing a pump assembly and for operatively connecting a pipette to the pump assembly via a flexible air tube. The pump assembly is adapted to independently accommodate a plurality of volume specific removable cylinder-plunger systems. The pipette control arrangement may further include a quick release trigger operated mechanism for rapidly and or in large volumes dispensing liquid from an attached pipette.

Abstract: A volume displacement pipette that includes a channel within the piston. The channel allows for cleaning fluids to be continuously run through the pipette tip for cleaning the tip. One end of the channel may be closed during normal operation of the pipette. Multiple pipettes may be combined into an array pipetter.

Abstract: A highly automated, high volume multichannel pipetting system which transfers liquid from mother plates to daughter plates, or from a fill station to daughter plates. The mother plates are stacked in one set of stacker assemblies, while the empty daughter plates are stacked in another stacker assembly. A plate handling assembly which is capable of moving the plates in three orthogonal directions retrieves the plates from the stacker assemblies, carries them to the pipetting head, and returns them to other stacker assemblies. The pipetting head is removable for replacement or repair thereof, or for insertion of another head assembly having a different number of pipetting channels. The head slides into the housing on slideways, and is retained in place by manually operable, threaded knobs mounted on shafts. The stacker assemblies include a chimney which is removable from a base. The plates may be stacked in the chimney and then inserted on the base.

Abstract: A pipette tip and mounting shaft combination in an air displacement pipette, the combination comprising a pipette tip mounting shaft having a radially stepped exterior comprising adjacent substantially cylindrical portions of different diameter and an annular sealing zone including an annular edge seal at an outermost edge of a radially extending shaft transition, a pipette tip including an annular sealing region having an inner sealing surface on a sidewall of the tip which in the sealing region is sufficiently thin as to expand slightly and form an interference fit and air tight seal between the sealing surface and the sealing zone when the sealing zone penetrates the sealing region, and axial penetration limiting means for limiting penetration of the shaft into the tip to limit axial contact between the sealing region and the sealing zone to a narrow annular band comprising the annular edge seal.

Abstract: A method and apparatus for an automated biological reaction system is provided. In the processing of a biological reaction system, there is a need for consistently placing an amount of fluid on a slide. In order to accomplish this, several methods are used including a consistency pulse and a volume adjust means. Moreover, in order to reliably operate an automated biological reaction system, the dispenser must be reliable, easy to assemble and accurate. Among other things, in order to accomplish this, the dispense chamber is substantially in line with the reservoir chamber, the reservoir chamber piston is removed, and the flow of fluid through the dispenser is simplified. Further, in order to operate the automated biological reaction system more reliably, the system is designed in modular pieces with higher functions performed by a host device and the execution of the staining operations performed by remote devices.

Abstract: A piston seal assembly for a pipette includes an O-ring having radially inner and outer surfaces and axially separated first and second surfaces. A seal includes a radially extending rim portion having axially separated first and second surfaces and an axially extending sleeve portion forming an opening. A seat includes an axially extending indexing portion and a radially extending engagement portion forming an opening and having axially separated first and second surfaces. The seal is positioned such that the pipette piston extends through the opening and the radially inner surface of the sleeve portion slidably engages the piston. The seat is positioned such that the piston extends through the opening, the first and second surfaces of the engagement portion engage the second surface of the rim portion and an end of the spring, respectively, and the radially outer surface of the indexing portion engages the inner surface of the pipette body.

Abstract: A hand-held pipettor comprising a piston received in one end of a cylinder, a pipettor tip removably secured to an opposite end of said cylinder, means for reciprocating said piston through a selected stroke to aspirate fluid into and to expel the thus aspirated fluid from said pipettor tip, mutually spaced stop members operatively associated with said manually driven means for defining the range of said stroke and motor driven means for varying the spacing between said stop members to thereby vary the volume of fluid being aspirated into and expelled from said pipettor tip.

Abstract: A pipette for use with a pipette tip to aspirate and dispense a quantity of liquid, comprising a housing, a pipette tip mounting shaft extending from the housing to receive a pipette tip, a pipette tip ejector mechanism for ejecting the pipette tip from the mounting shaft, energy storage means, means for storing energy in the energy storage means and means for releasing energy from the energy storage means to assist the tip ejector mechanism in the ejecting of the pipette tip from the mounting shaft.

Abstract: A device (1) for aspirating and dispensing liquid samples having a pump (2), which comprises a cylindrical chamber (3), a piston (4) movable in this cylindrical chamber, and a piston drive (5) engaging on the piston. The device additionally comprises a pulse generator (6), which effects dispensing of samples from a liquid by generating pressure waves in this liquid and a tip (8) connected via a line (7) with the cylindrical chamber (3), with the piston drive (5) comprising a first drive (9) and a second drive (10), implemented as a pulse generator (6). Such a device comprises a channel (27) for rinsing or flushing the cylindrical chamber (3), with the channel (27) discharging into the cylindrical chamber (3). Furthermore, the invention also concerns systems with, for example, 384 or more such devices that are arranged in an array.

Abstract: A device for transferring cells present in fluid media is provided which is especially useful for in vitro fertilization techniques and intracytoplasmic sperm injection procedures.

Abstract: A syringe for accurately metering small volumes of fluid samples is provided with dual resolution capabilities. The syringe permits the aspiration of a tiny sample and also the dilution of a tiny sample with a much larger volume of reagent with the same syringe. The syringe also allows the aspiration of a minute fluid sample and the touchless transfer of the fluid sample from the tip of the syringe. The present invention allows the aspiration resolution to differ from the dispensing resolution. The dual resolution capabilities also permits the present invention to be implemented into existing conventional syringe drive system. The syringe may include a housing, a piston within the housing, and a plunger extending from the housing. A chamber is formed in the housing between the plunger and a sealing means and between the piston and the inner surface of the housing.

Abstract: A syringe for accurately metering small volumes of fluid samples and with dual resolution capabilities is provided. The syringe permits the aspiration of a tiny sample and also the dilution of a tiny sample with a much larger volume of reagent with the same syringe. The syringe also allows the aspiration of a minute fluid sample and the touchless transfer of the fluid sample from the tip of the syringe. The present invention allows the aspiration resolution to differ from the dispensing resolution. The dual resolution capability also permits the present invention to be substituted for a conventional syringe in existing conventional syringe drive system. The syringe may include a housing, a piston within the housing, and a plunger extending from the housing. A chamber is formed in the housing between the plunger and a sealing means and between the piston and the inner surface of the housing.

Abstract: A method for detaching a barrier means adapted to the end part of the suction device for closing an opening in the end part by the movement of a plunger intended for changing the volume of a cylindrical space provided in the end part whereby the barrier means is removed by bringing means for limiting the movement of the plunger in the cylindrical space, e.g. means intended for removing the disposable tip, in such a position that the plunger can be brought into contact with the barrier means for detaching the barrier means from the end part of the suction device.

Abstract: A position of a piston fluid-tightly sliding along an inner surface of a pipette is instantaneously changed by a short distance to jet a portion of a liquid in the pipette through the nozzle of the pipette as a drop. The instantaneously changed position is provided by a motor which is commonly used for moderately changing the position of the piston to taking-in and taking-out the liquid. The instantaneous minute position changing may be provided with a piezoelectric actuator. An attachable nozzle cap having a nozzle-cap nozzle (through hole) of which diameter is smaller than that of the nozzle of the pipette may be used. The portion of the liquid jetted from the pipette may be detected. The instantaneous changing may be repeated to jet a desired amount of said liquid. The short distance may be adjusted in accordance with the desired amount.

Abstract: A proportioning device, comprising a manually operable actuating device, a sensor associated with the actuating device for detecting a force manually exerted on the actuating device, an electric driving motor, an electric control connected to the sensor and electric driving motor for controlling the driving motor during the detection by the sensor of a force exerted on the actuating device, an electric voltage supply connected to the sensor, electric driving motor, and electronic control, and a displacement device coupled to the actuating device and electric driving motor for proportioning a liquid.

Abstract: An air displacement pipette having axially spaced annular sealing and lateral support zones and regions on the pipette's mounting shaft and tip, respectively, the annular sealing zone comprising an annular sealing surface outward of an outer surface of the mounting shaft at a lower end thereof and a sidewall of the pipette tip in the sealing region being sufficiently thin as to expand slightly and form an interference fit and air tight seal between the sealing surface and the sealing region when the sealing zone penetrates the sealing region and an outer diameter of the mounting shaft in the lateral support zone being equal to or slightly greater than an inner diameter of the pipette tip in the lateral support region to produce an secondary interference fit or air tight seal between the mounting shaft and pipette tip.

Abstract: A method for detecting the type of replaceable piston-cylinder unit mounted in pipetting or dosing apparatus with the help of a code marking on the piston rod head, so as to eliminate the influence of the chain of tolerances piston rod head/piston rod/piston/cylinder bottom/cylinder flange so that, to a certain extent, larger tolerances may be tolerated for the parts of the piston-cylinder units involves generating relative movement between the piston rod head and a detection device, and thereby detecting a reference point on the piston head with the detection device from laterally of the piston head, and generating relative movement between the piston rod head and the detection device and thereby detecting a code marking of the piston rod head in order to determine the type of piston-cylinder unit mounted.

Abstract: An inoculation storage assembly and method of preserving sterility including an inoculation device (20), a storage rack or container (84, 184), and a handling tool (60, 160). The inoculation device (20) being an elongated ember (22) with a gripping section (24), an inoculation section (26), and a seal (25) carried by elongated member (22). The seal (25) preferably having an arcuate surface (19) for sealing engagement against a seal contact surface (162, 262) in a cavity (86, 186) in the storage rack (84, 184). The storage container (84, 184) including an open upper end or opening (88) and a seal contact surface (162, 262) dimensioned to sealingly receive the seal (25), with the inoculation device (20) being mounted in sealed relation to the cavity (86). A handling tool (60, 160) capable of releasable coupling to gripping section (24) of the inoculation device (20) is provided. A method of using the inoculation storage assembly and preserving sterility is also disclosed.

Abstract: A hybrid pipette including a pipette casing (11) and a slide shaft (22) vertically movable in response to the operation of a pushbutton (23). A plunger (31) is disposed below the slide shaft and urged upwardly by a spring (33, 34). An engagement member (41) is coaxially and movably fitted on the slide shaft (22) and extends through a hole (12a1) in a casing member (11) so as to be movable at least vertically. An electric motor (51) is provided on an axis different from the axis of the slide shaft and operatively engaged with the engagement member (41). In a manual operation mode, the slide shaft (22) and the plunger (31) move vertically in response to the operation of the pushbutton (23) to perform suction and discharge of a liquid. In a motor-driven operation mode, the engagement member (41) is driven to move vertically by the electric motor (51), whereby the plunger (31) is moved vertically to perform suction and discharge of a liquid.

Abstract: There is provided a method and apparatus for aspirating a volume of liquid into a syringe from a sample of the liquid. A substantial portion of the liquid in the syringe is subsequently dispensed from the syringe and returned to the sample. Accordingly, a small portion of the aspirated liquid is retained in the syringe. One or more nanoliter volumes of the liquid retained in the syringe are then dispensed from the syringe to a container for further use or analysis. It will be understood, therefore, that the volume of the originally aspirated liquid is substantially larger than the volume of liquid dispensed for further use or analysis. The invention also includes a method and apparatus for aspirating and dispensing a plurality of liquids by using a plurality of syringes, and also can be used to dispense liquids onto microplates.

Abstract: Devices and methods for integrated packaging, shipping, storage and precise dispensing of extremely small volumes of liquids such as aqueous solutions and compounds dissolved in organic solvents are disclosed. Devices of the invention include a sealed reservoir with an integrated metering tap. The tap includes a metering tube, which is translatable between a fill position inside the reservoir and an expel position outside the reservoir. The metering tube includes: (1) a tube end closure in a lower portion of the tube, (2) a port above the tube end closure, and (3) a piston in an upper portion of the tube. The piston is movable between a down position that seals the side port and an up position above the port. Movement of the piston from the up position to the down position can displace from 10 nanoliters to 20 microliters, e.g., from 20 nanoliters to 2 microliters, or 50 nanoliters to 500 nanoliters.

Abstract: An ergonomic, manually precisely controllable return springless air displacement pipette relying upon the friction of a piston seal to maintain a plunger unit of the pipette in any axial location established by a user of the pipette.

Abstract: An air displacement pipette having axially spaced annular sealing and lateral support zones and regions on the pipette's mounting shaft and tip, respectively, the annular sealing zone comprising an annular sealing surface outward of an outer surface of the mounting shaft at a lower end thereof and a sidewall of the pipette tip in the sealing region being sufficiently thin as to expand slightly and form an interference fit and air tight seal between the sealing surface and the sealing region when the sealing zone penetrates the sealing region and an outer diameter of the mounting shaft in the lateral support zone being equal to or slightly greater than an outer diameter of the pipette tip in the lateral support region to produce an secondary interference fit or air tight seal between the mounting shaft and pipette tip.