Liquid sample dispensing methods for precisely delivering liquids without crossover

• US 6,463,969 B1
• Filed: 04/10/2001
• Issued: 10/15/2002
• Est. Priority Date: 04/10/2001
• Status: Expired

• Current Assignee: Siemens Healthcare Diagnostics Incorporated (Siemens AG)
• Original Assignee: Dade Behring, Inc. (Siemens AG)
• Inventors: Devlin, William Jackson Sr.
• Primary Examiner(s): Douglas, Steven O.
• Application Number:
  US09/829,651
• Publication Number:
  US 20020144747A1
• Time in Patent Office: 553 Days
• Field of Search: 141/129, 141/130, 422/99, 422/100, 738/633.2, 738/649.1, 436/43, 436/180, 356/246
• US Class Current: 141/130
• CPC Class Codes: B01L 3/0293 for liquids
• CPC Class Codes: B01L 9/00 Supporting devices; Holding devices
• CPC Class Codes: G01N 2035/1034 Transferring microquantities of liquid
• CPC Class Codes: G01N 35/1016 Control of the volume dispensed or introduced
• CPC Class Codes: Y10T 436/11 Automated chemical analysis
• CPC Class Codes: Y10T 436/2575 Volumetric liquid transfer

Abstract

A method for reducing carryover of and delivering liquid taken from a source container by a dispensing means to a target container by spinning the target container so that any liquid within the target container is removed from the dispensing means prior to dispensing liquid into the target container.

Claims

1. A method for reducing carryover of first target vessel liquid contained in a first target vessel and a sampling pipette containing source liquid, the method comprising:

spinning the first target vessel so that first target vessel liquid contained therein is displaced away from the central portion of the target vessel;

forming a first droplet of source liquid at the nozzle of the sampling pipette;

lowering the sampling pipette into the central portion of the target vessel a distance sufficient to cause the first droplet of source liquid to contact the bottom of the first target vessel without the sampling pipette or the droplet touching first target vessel liquid disposed therein, so that the first droplet of source liquid is spun off from the sampling pipette into the target vessel.

2. The method of claim 1 further comprising:

spinning a second target vessel so that second target vessel liquid contained therein is displaced away from the central portion of the second target vessel;

forming a second droplet of source liquid at the nozzle of the sampling pipette;

lowering the sampling pipette into the central portion of the second target vessel a distance sufficient to cause the second droplet of source liquid to contact the bottom of the second target vessel without the sampling pipette or the droplet touching second target vessel liquid disposed therein, so that the second droplet of source liquid is spun off from the sampling pipette into the second target vessel.

3. The method of claim 1 wherein the target vessel is axially symetrical.

4. The method of claim 1 wherein the sampling pipette is either a permanent or disposable sampling pipette.

5. A method for reducing carryover of first target vessel liquid contained in a first target vessel and a sampling pipette containing source liquid, the method comprising:

inclining the first target vessel so that first target vessel liquid contained therein is displaced away from the central portion of the target vessel;

forming a first droplet of source liquid at the nozzle of the sampling pipette;

lowering the sampling pipette into the central portion of the target vessel a distance sufficient to cause the first droplet of source liquid to contact the bottom of the first target vessel without the sampling pipette or the droplet touching first target vessel liquid disposed therein, so that the first droplet of source liquid is spun off from the sampling pipette into the target vessel.

6. The method of claim 5 further comprising:

inclining a second target vessel so that second target vessel liquid contained therein is displaced away from the central portion of the second target vessel;

forming a second droplet of source liquid at the nozzle of the sampling pipette;

lowering the sampling pipette into the central portion of the second target vessel a distance sufficient to cause the second droplet of source liquid to contact the bottom of the second target vessel without the sampling pipette or the droplet touching second target vessel liquid disposed therein, so that the second droplet of source liquid is spun from the sampling pipette into the target vessel.

7. The method of claim 5 wherein the target vessel is axially symetrical.

8. The method of claim 5 wherein the sampling pipette is either a permanent or disposable sampling pipette.

9. A method for delivering an amount of liquid from a source vessel into a target vessel, the method comprising:

aspirating a known volume of liquid from the source container into an aspirating probe;

dispensing a major portion of the volume of liquid into the target vessel while the target vessel is stationary, at the same time leaving a minor portion of liquid within the aspirating probe;

spinning the target vessel so that the major portion of liquid contained therein is displaced away from the central portion of the target vessel;

forming a droplet of the minor portion of source liquid at the nozzle of the sampling pipette;

lowering the sampling pipette into the central portion of the target vessel a distance sufficient to cause the droplet of source liquid to contact the bottom of the target vessel without the droplet touching liquid disposed therein, so that the droplet of source liquid is spun off from the sampling pipette into the target vessel.

10. The method of claim 9 wherein the target vessel is axially symetrical.

11. The method of claim 9 wherein the sampling pipette is either a permanent or disposable sampling pipette.

12. A method for delivering an amount of source liquid from a source vessel into a target vessel containing target liquid therein, the method comprising:

aspirating a known volume of source liquid from the source container into an aspirating probe;

spinning the target vessel so that target liquid contained therein is displaced away from the central portion of the target vessel;

lowering the sampling pipette into the central portion of the target vessel a distance sufficient to cause a major portion of the volume of source liquid to contact the bottom of the target vessel without the major portion touching target liquid disposed therein, so that the major portion of source liquid is spun off from the sampling pipette into the target vessel;

continuing to spin the target vessel so that all liquid contained therein is displaced away from the central portion of the target vessel;

forming a droplet of the remaining droplet portion of source liquid at the nozzle of the sampling pipette;

lowering the sampling pipette into the central portion of the target vessel a distance sufficient to cause the remaining droplet portion of source liquid to contact the bottom of the target vessel without the remaining droplet portion touching liquid disposed therein, so that the remaining droplet portion of source liquid is spun off from the sampling pipette into the target vessel.

13. The method of claim 12 wherein the target vessel is axially symmetrical.

14. The method of claim 13 wherein the sampling pipette is either a permanent or disposable sampling pipette.