Liquid sample handling system

Claim 1

An apparatus to prevent cross-contamination or errors in handling small liquid samples during filling, transferring or mixing of such liquid samples by repetitive use of the same pipette to transfer liquids between a plurality of sample receptacles having different quantities or types of liquid therein which includes a plurality of syringes, each having a barrel portion and a pipette tip member securable thereto for insertion into said sample receptacles to withdraw liquids from or inject liquids into said receptacles, and each syringe barrel including a body portion having a cylinder formed therein, a plunger positioned in and fluid sealed for reciprocal motion of said plunger through said cylinder, an elongated pipette tip member for covering the other end of said cylinder and forming a substantial portion of the fluid volume of said barrel, said tip member having one end frictionally engageable with a portion of the sidewall surface of said body portion to form a fluid seal with said cylinder, reciprocal means having finger members slidably surrounding the exterior of said barrel to contact said tip member to frictionally disengage said tip member from said sidewall surface, means for supporting a plurality of said pipette tip members in a vertical position for selective frictional engagement with said sidewall surface, means for receiprocating each of said barrels to frictionally engage said tips with said surface, and means for actuating said reciprocal means to disengage said tip member from said cylinder, whereby a different pipette tip member may be selectively and automatically changed after any insertion into fluid in a sample receptacle to prevent cross-contamination or errors in dilution or transfer of successive samples by residual fluid carried by a pipette tip member.

Claim 2

An apparatus to prevent cross-contamination or errors in handling small liquid samples during filling, transferring or mixing of such liquid samples by repetitive use of the same pipette to transfer liquids between a plurality of sample receptacles having different quantities or types of liquid therein which includes a plurality of syringes, each having a barrel portion and a pipette tip member securable thereto for insertion into said sample receptacles to withdraw liquids from or inject liquids into said receptacles, and each syringe barrel including a body portion having a cylinder formed therein, a plunger positioned in and fluid sealed for reciprocal motion of said plunger through said cylinder, an elongated pipette tip member for covering the other end of said cylinder and forming a substantial portion of the fluid volume of said barrel, said tip member having one end frictionally engageable with a portion of the sidewall surface of said body portion to form a fluid seal with said cylinder, reciprocal means having finger members slidably surrounding the exterior of said barrel to contact said tip member to frictionally disengage said tip member from said sidewall surface, means for supporting a plurality of said pipette tip members in a vertical position for selective frictional engagement with said sidewall surface, means for receiprocating each of said barrels to frictionally engage said tips with said surface, and means for actuating said reciprocal means to disengage said tip member from said cylinder, whereby a different pipette tip member may be selectively and automatically changed after any insertion into fluid in a sample receptacle to prevent cross-contamination or errors in dilution or transfer of successive samples by residual fluid carried by a pipette tip member.

Claim 5

A method for effecting sterile, automatic transfer or dilution of liquid samples between a plurality of rows of liquid receptacles comprising the steps of: a) positioning said plurality of rows of liquid receptacles for horizontal movement on a support table with each row of said plurality being indexable beneath a row of pipettes at a first work station, each of said liquid receptacles being filled with a predetermined volume of liquid at a known concentration; b) positioning a row of pipettes on a head assembly above said support table and vertically reciprocable relative thereto; c) arranging at least a row of pipette tips for horizontal movement on said support table at a second work station thereon; d) moving said support table to register said row of pipette tips with the pipettes on said head assembly; e) lowering said pipettes to engage the tips in the registered row and picking up the engaged tips; f) moving said table to index a row of receptacles at said first work stations under said row of pipettes; g) inserting the engaged tips in the liquid in said indexed row of receptacles and withdrawing at least some of the liquid therefrom into said pipettes; h) raising said pipettes; i) moving said table to index another row of receptacles under said pipettes; j) lowering said pipettes and expelling the liquid in said pipettes into the receptacles of said other row; k) raising said pipettes; 1) moving the table to bring a selected positon at said second work station into alignment with said pipettes; and m) discharging said engaging tips from said pipettes.

Claim 6

A method for effecting sterile, automatic transfer or dilution of liquid samples between a plurality of rows of liquid receptacles comprising the steps of: a) positioning said plurality of rows of liquid receptacles for horizontal movement on a support table with each row of said plurality being indexable beneath a row of pipettes at a first work station, each of said liquid receptacles being filled with a predetermined volume of liquid at a known concentration; b) positioning a row of pipettes on a head assembly above said support table and vertically reciprocable relative thereto; c) arranging at least a row of pipette tips for horizontal movement on said support table at a second work station thereon; d) moving said support table to register said row of pipette tips with the pipettes on said head assembly; e) lowering said pipettes to engage the tips in the registered row and picking up the engaged tips; f) moving said table to index a row of receptacles at said first work stations under said row of pipettes; g) inserting the engaged tips in the liquid in said indexed row of receptacles and withdrawing at least some of the liquid therefrom into said pipettes; h) raising said pipettes; i) moving said table to index another row of receptacles under said pipettes; j) lowering said pipettes and expelling the liquid in said pipettes into the receptacles of said other row; k) raising said pipettes; 1) moving the table to bring a selected positon at said second work station into alignment with said pipettes; and m) discharging said engaging tips from said pipettes.