Multiple pipette samples

• US 5,000,921 A
• Filed: 02/08/1990
• Issued: 03/19/1991
• Est. Priority Date: 10/24/1986
• Status: Expired due to Term

• Current Assignee: James Hrudicka, Richard W. Hanaway
• Original Assignee: James Hrudicka, Richard W. Hanaway
• Inventors: Hrudicka, James, Hanaway, Richard W.
• Primary Examiner(s): Warden, Robert J.
• Assistant Examiner(s): Johnston, Jill
• Application Number:
  US07/490,162
• Time in Patent Office: 404 Days
• Field of Search: 422/100, 73/863.32, 73/864.11, 73/864.14, 435/301
• US Class Current: 422/520
• CPC Class Codes: B01L 3/021 Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids
• CPC Class Codes: G01N 2035/00237 Handling microquantities of analyte, e.g. microvalves, capillary networks
• CPC Class Codes: G01N 35/1065 Multiple transfer devices
• CPC Class Codes: Y10T 156/1002 with permanent bending or reshaping or surface deformation of self sustaining lamina

Abstract

A pipette sampling device for removing and transferring a plurality of liquid samples consists of an improved structure which allows a low cost manufacturing process, the use of a minimum amount of material in such process, and a pipette cavity shaped such that hydraulic principles insure accuracy during filling and dispensing. The pipette sampling device is positionable within a filling tray which permits an initial filling of the pipettes by a liquid through capillary action, and an actuating device is then attached over the pipettes. The actuating device provides a vacuum so that the liquid is drawn into each pipette cavity until the walls and rims of all of the cavities are completely wetted and a stretched meniscus is formed at the top of each cavity. The actuator may then be utilized to effect the dispensing of the liquid in each pipette cavity through a provided pressure. To accomplish this process, the sampling device is constructed to include a manifold which is designed as an inflexible, rigid monocoque structure.

Claims

1. A process of using a multiple pipette sampler, said multiple pipette sampler comprising a plurality of pipettes, each of said pipettes including a narrow tip and a rim opposite said tip, said multiple pipette sampler further comprising a manifold above and in liquid communication with said pipettes, said multiple pipette sampler further comprising a means for varying the air pressure in said manifold;

said process comprising the steps of;

inserting said plurality of pipettes into a liquid retained within a filling tray while said manifold is in liquid communication with the atmosphere, thereby permitting capillary action to partially fill said pipettes with a uniform volume of said liquid;

decreasing the pressure in said manifold enough to draw said liquid upwards to a level above said rims of said pipettes, thereby effecting a complete wetting of interior portions of said pipettes, said liquid being retained at said level by the formation of stretched convexly shaped menisci;

increasing the air pressure in said manifold enough to allow said menisci to assume a concave shape, thereby retaining said pipettes in a completely liquid filled condition;

removing said plurality of pipettes from said filling tray and transferring said plurality of pipettes to receiving wells, said pipettes being placed below the level of liquid in said wells;

further increasing the air pressure in said manifold enough to dispense said liquid in pipettes into said receiving wells; and

,

removing said plurality of pipettes from said receiving panel whereby surface tension removes all but small uniform volumes of said liquid from said pipette tips, said uniform volumes being substantially equal to those present immediately after insertion of the pipettes into said filling tray.

2. A multiple pipette sampler, comprising:

a thin PVC plastic pipette sheet having an initial thickness between 0.015 and 0.020 inches;

a plurality of pipettes thermoformed in said pipette sheet and disposed in spaced parallel relation, said pipettes forming a uniform array extending perpendicularly from a bottom surface of said pipette sheet;

each of said pipettes forming a half hour-glass configuration having a larger diameter upper portion connected by a circular rim with said pipette sheet, each of said pipettes tapering to a small diameter tip portion forming a capillary tube for inducting a precise volume of sample liquid;

a concave housing thermoformed from a plastic sheet;

said housing having a top surface overlying an upper surface of said pipette sheet;

a plurality of concave depressions in said housing top surface, forming stiffening members engaging said upper surface of said pipette sheet, said stiffening members secured to said pipette sheet at intersticial zones between said pipettes;

said housing top surface connected to downwardly extending side wall portions;

a peripheral sealing edge formed in said side wall portions, said sealing edge extending in parallel engaging relation with a peripheral edge of said pipette sheet and secured thereto thereby forming a manifold in direct fluid communication with each of said pipettes; and

a lower peripheral skirt portion of said housing extending downwardly from said sealing edge and partially surrounding said pipettes.

3. The multiple pipette sampler of claim 2, further comprising:

a filling tray thermoformed from a plastic sheet, said filling tray having upwardly extending side wall portions dimensioned for engagement with said housing skirt;

a plurality of vent notches at corner portions of said filling tray; and

a plurality of concave liquid holding troughs formed in said tray, said troughs disposed to receive said pipettes when said housing is placed over said tray.

4. The multiple pipette sampler of claim 2, further comprising:

an aperture formed through said top surface of said housing, between said concave depressions; and

a sealing washer surrounding said aperture in coaxial relation therewith, said washer secured to said housing top surface and including peripheral edge portions overlying at least two of said concave depressions.

5. The multiple pipette sampler of claim 4, further comprising:

a pressure actuator having a body including a piston slidably received in an internal cylinder;

a passage extending through a bottom end face of said actuator body and in fluid communication with said cylinder; and

a sealing gasket secured on an end face of said bottom end face of said actuator body in coaxial relation with said passage, said sealing gasket dimensioned for engagement with said sealing washer on said housing top surface.

6. The multiple pipette sampler of claim 5, further comprising:

a pair of pivotal hook members pivotally mounted on said actuator body on opposite sides of said sealing gasket, said hook members including manually manipulable handle portions for engaging said hook members with said peripheral edge portion of said sealing washer, whereby said actuator passage may be placed in sealed fluid communication with said manifold.

7. The multiple pipette sampler of claim 6, further comprising:

a piston rod secured to said piston and extending upwardly through a top end face of said actuator body;

a transverse handle secured to an upper end of said piston rod;

a first adjustable threaded stop in said top end face of said actuator body disposed for abutment with said transverse handle;

an extended portion of said actuator body extending upwardly from said top end face;

a transverse flange on said extended portion overlying said transverse handle;

a second adjustable threaded stop in said transverse handle disposed for abutment with said transverse flange;

a first inclined cam surface formed on an extended edge of said handle;

a manually operable spring biased catch mounted for linear movement in said actuator body extended portion; and

said catch having a second inclined cam surface configured to allow vertical movement of said handle above said catch and to prevent downward movement of said handle past said catch.

8. A multiple pipette sampler, comprising:

a thin PVC plastic pipette sheet having an initial thickness between 0.015 and 0.020 inches;

a plurality of pipettes thermoformed in said pipette sheet and disposed in spaced parallel relation, said pipettes forming a uniform array extending perpendicularly from a bottom surface of said pipette sheet;

each of said pipettes forming a half hour-glass configuration having a larger diameter upper portion connected by a circular rim with said pipette sheet, each of said pipettes tapering to a small diameter tip portion forming a capillary tube for inducting a precise volume of sample liquid;

a concave housing thermoformed from a plastic sheet;

said housing having a top surface overlying an upper surface of said pipette sheet;

a plurality of concave depressions in said housing top surface, forming stiffening members engaging said upper surface of said pipette sheet, said stiffening members secured to said pipette sheet at intersticial zones between said pipettes;

said housing top surface connected to downwardly extending side wall portions;

a peripheral sealing edge formed in said side wall portions, said sealing edge extending in parallel engaging relation with a peripheral edge of said pipette sheet and secured thereto, thereby forming a manifold in direct fluid communication with each of said pipettes;

a lower peripheral skirt portion of said housing extending downwardly from said sealing edge and partially surrounding said pipettes;

a filling tray thermoformed from a plastic sheet, said filling tray having upwardly extending side wall portions dimensioned for engagement with said housing skirt;

a plurality of vent notches at corner portions of said filling tray;

a plurality of concave liquid holding troughs formed in said tray, said troughs disposed to receive said pipettes when said housing is placed over said tray;

an aperture formed through said top surface of said housing, between said concave depressions;

a sealing washer surrounding said aperture in coaxial relation therewith, said washer secured to said housing top surface and including peripheral edge portions overlying at least two of said concave depressions;

a pressure actuator having a body including a piston slidably received in an internal cylinder;

a passage extending through a bottom end face of said actuator body and in fluid communication with said cylinder;

a sealing gasket secured on an end face of said bottom end face of said actuator body in coaxial relation with said passage, said sealing gasket dimensioned for engagement with said sealing washer on said housing top surface;

a pair of pivotal hook members pivotally mounted on said actuator body on opposite sides of said sealing gasket, said hook members including manually manipulable handle portions for engaging said hook members with said peripheral edge portions of said sealing washer, whereby said actuator passage may be placed in sealed fluid communication with said manifold;

a piston rod secured to said piston and extending upwardly through a top end face of said actuator body;

a transverse handle secured to an upper end of said piston rod;

a first adjustable threaded stop in said top end face of said actuator body disposed for abutment with said transverse handle;

an extended portion of said actuator body extending upwardly from said top end face;

transverse flange on said extended portion overlying said transverse handle;

a second adjustable threaded stop in said transverse handle disposed for abutment with said transverse flange;

a first inclined cam surface formed on an extended edge of said handle;

a manually operable spring biased catch mounted for linear movement in said actuator body extended portion; and

said catch having a second inclined cam surface configured to allow vertical movement of said handle above said catch and to prevent downward movement of said handle past said catch.

9. A multiple pipette sampler, comprising:

a plurality of pipettes formed in a thin sheet, thereby forming a pipette sheet, each of said pipettes terminating in a narrow tip, each of said pipettes having a rim proximate said thin sheet and opposite said tip, said pipettes being thermoformed in said thin sheet;

a housing sealingly attachable to said pipette sheet, said attachment of said housing to said sheet forming a manifold in fluid communication with each of said pipettes;

pressure varying means operably attachable to said manifold, said pressure varying means alternatively permitting an evacuation and pressurization of said manifold; and

strengthening means whereby said attached pipette sheet and housing form a rigid monocoque structure, thereby permitting the transmission of shear forces and stresses without deformation of a planar orientation of said pipette sheet.

10. The multiple pipette sampler of claim 9, wherein said manifold includes an attachment means whereby said pressure varying means may be joined physically as well as pneumatically to said manifold, thereby allowing said pipette sheet, said housing, and said pressure varying device to be easily transported together during usage of said pipette sampler.

11. The multiple pipette sampler of claim 9, wherein a film of hydrophobic plastic surrounds said rim of each of said pipettes.

12. A multiple pipette sampler, comprising:

a plurality of pipettes formed in a thin sheet, thereby forming a pipette sheet, each of said pipettes terminating in a narrow tip, each of said pipettes having a rim proximate said thin sheet and opposite said tip, said pipettes being thermoformed in said thin sheet;

a housing sealingly attachable to said pipette sheet, said attachment of said housing to said sheet forming a manifold in fluid communication with each of said pipettes;

pressure varying means operably attachable to said manifold, said pressure varying means alternatively permitting an evacuation and pressurization of said manifold; and

said pipette sheet attached to said housing by a dielectric heating process.

13. The multiple pipette sampler of claim 12, wherein said manifold includes an attachment means whereby said pressure varying means may be joined physically as well as pneumatically to said manifold, thereby allowing said pipette sheet, said housing, and said pressure varying device to be easily transported together during usage of said pipette sampler.

14. The multiple pipette sampler of claim 12, wherein a film of hydrophobic plastic surrounds said rim of each of said pipettes.

15. A multiple pipette sampler, comprising:

a plurality of pipettes formed in a thin sheet, thereby forming a pipette sheet, each of said pipettes terminating in a narrow tip, each of said pipettes having a rim proximate said thin sheet and opposite said tip, said pipettes being thermoformed in said thin sheet;

a housing sealingly attachable to said pipette sheet, said attachment of said housing to said sheet forming a manifold in fluid communication with each of said pipettes;

pressure varying means operably attachable to said manifold, said pressure varying means alternatively permitting an evacuation and pressurization of said manifold; and

each of said pipettes shaped like the upper half of an hour glass, each of said pipettes having a narrow stem and a wider body, said narrow stems functioning as capillary tubes, said capillarity permitting a substantial identity between an initial partially filled volume and a final volume remaining in each of said pipettes after usage of said pipettes.

16. The multiple pipette sampler of claim 15, wherein said manifold includes an attachment means whereby said pressure varying means may be joined physically as well as pneumatically to said manifold, thereby allowing said pipette sheet, said housing, and said pressure varying device to be easily transported together during usage of said pipette sampler.

17. The multiple pipette sampler of claim 15, wherein a film of hydrophobic plastic surrounds said rim of each of said pipettes.

18. A multiple pipette sampler, comprising:

a thin plastic pipette sheet;

a plurality of pipettes formed in said pipette sheet and disposed in spaced parallel relation, said pipettes extending generally perpendicularly from a bottom surface of said pipette sheet;

each of said pipettes forming a half hour-glass configuration having a larger diameter upper portion connected by a circular rim with said pipette sheet, each of said pipettes tapering to a small diameter tip portion forming a capillary tube for inducting a precise volume of sample liquid;

a concave housing;

said housing having a top surface overlying an upper surface of said pipette sheet;

a plurality of concave depressions in said housing top surface, forming stiffening members engaging said upper surface of said pipette sheet, said stiffening members secured to said pipette sheet at intersticial zones between said pipettes;

said housing top surface connected to downwardly extending side wall portions; and

a peripheral sealing edge formed in said side wall portions, said sealing edge extending in sealing relation with a peripheral edge of said pipette sheet and secured thereto, thereby forming a manifold in direct fluid communication with each of said pipettes.

19. The multiple pipette sampler of claim 18, further comprising:

a filling tray formed from a plastic sheet, said filling tray having upwardly extending side wall portions dimensioned for engagement with said housing skirt;

a plurality of vent notches at corner portions of said filling tray; and

a plurality of concave liquid holding troughs formed in said tray, said troughs disposed to receive said pipettes when said housing is placed over said tray.

20. The multiple pipette sampler of claim 18, further comprising:

an aperture formed through said top surface of said housing, between said concave depressions; and

a sealing washer surrounding said aperture in coaxial relation therewith, said washer secured to said housing top surface and including peripheral edge portions overlying at least two of said concave depressions.

21. The multiple pipette sampler of claim 20, further comprising:

a pressure actuator having a body including a piston slidably received in an internal cylinder;

a passage extending through a bottom end face of said actuator body and in fluid communication with said cylinder; and

a sealing gasket secured on an end face of said bottom end face of said actuator body in coaxial relation with said passage, said sealing gasket dimensioned for engagement with said sealing washer on said housing top surface.

22. The multiple pipette sampler of claim 18, wherein said manifold includes an attachment means whereby said pressure varying means may be joined physically as well as pneumatically to said manifold, thereby allowing said pipette sheet, said housing, and said pressure varying device to be easily transported together during usage of said pipette sampler.

23. The multiple pipette sampler of claim 18, wherein a film of hydrophobic plastic surrounds said rim of each of said pipettes.