Pipetting apparatus and a method of pipetting a liquid

• US 20010016358A1
• Filed: 02/13/2001
• Published: 08/23/2001
• Est. Priority Date: 02/18/2000
• Status: Active Grant

• Current Assignee: Hitachi KOKI Company Limited (Koki Holdings Co., Ltd.)
• Original Assignee: Hitachi KOKI Company Limited (Koki Holdings Co., Ltd.)
• Inventors: Sato, Toyosaku, Inaniwa, Masahiro, Osawa, Hidetaka
• Granted Patent: US 6,773,927 B2
• Time in Patent Office: Days
• US Class Current: 436/180
• CPC Class Codes: B01L 3/0217 of the plunger pump type medical syringes A61M
• CPC Class Codes: Y10T 436/2575 Volumetric liquid transfer

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.

Claims

1. A pipetting apparatus comprising:

a pipette having a nozzle;

pipette holding means for holding said pipette;

a piston fluid-tightly sliding along an inner wall of said pipette;

piston holding means for holding a portion of said piston; and

instantaneous position changing means for changing a position of said piston with said piston holding means by a short distance with respect to said pipette holding means to jet a portion of a liquid in said pipette through said nozzle as a drop.

2. A pipetting apparatus as claimed in

claim 1

, wherein said instantaneous position changing means comprises a motor, said pipetting apparatus further comprises moderately position changing means for moderately changing said position of said piston with said motor to suck and discharge a desired amount of said liquid, and said motor is commonly used between said instantaneous position charging means and said moderately position changing means.

3. A pipetting apparatus as claimed in

claim 1

, wherein said instantaneous position changing means comprises a piezoelectric actuator.

4. A pipetting apparatus as claimed in

claim 1

, further comprising an attachable nozzle cap being attachable to said pipette and having a nozzle-cap nozzle for jetting said portion of said liquid through said nozzle and said nozzle-cap nozzle, a diameter of said nozzle-cap nozzle being smaller than that of said nozzle.

5. A pipetting apparatus as claimed in

claim 1

, further comprises;

detection means for detecting said portion of said liquid jetted from said pipette; and

confirming means in response to said instantaneous position changing means and said detection means for confirming that said portion of said liquid is jetted and outputting a confirmed result.

6. A method of pipetting a liquid with a pipette and a piston fluid-tightly sliding along an inner wall of said pipette comprising the steps of:

(a) sucking said liquid with said piston; and

(b) instantaneously changing a position of said piston with respect to said pipette by a short distance to jet a portion of a liquid in said pipette as a drop through said nozzle.

7. A method as claimed in

claim 6

, wherein said step (b) is repeated to jet a desired total amount of said liquid.

8. A method as claimed in

claim 6

, further comprising the step of determining said short distance in accordance with a desired amount of said liquid, wherein in step (b), said position of said piston is changed instantaneously by said short distance determined in accordance with said desired amount.

9. A method as claimed in

claim 6

, between said steps (a) and (b), further comprising the steps of attaching an attachable nozzle cap to said pipette at said nozzle, said attachable nozzle cap having a nozzle-cap nozzle of which diameter is smaller than that of said nozzle;

and

changing said position of said piston to fill with said liquid in said attachable nozzle cap, wherein in said step (b), said portion of said liquid is jetted through said nozzle and said nozzle-cap nozzle.

10. A method as claimed in

claim 6

, further comprising the steps of:

detecting said portion of said liquid jetted from said pipette; and

confirming that said portion of said liquid is jetted in response to said instantaneous position changing means and said detection means and outputting a confirmed result.

11. A pipetting apparatus comprising:

pipette holding means for holding a pipette having a nozzle and a piston fluid-tightly sliding along an inner wall of said pipette;

piston holding means for holding a portion of said piston; and

moving means for moving said piston with said piston holding means toward said nozzle by a short distance for a short time interval to jet a portion of a liquid in said pipette as a drop through said nozzle.

12. A pipetting apparatus as claimed in

claim 11

, wherein an amount of said drop is determined in accordance with a size of said nozzle, said short distance and said short time interval.