Abstract: There is disclosed herein a machine for performing nucleic acid amplification under computer control. The machine utilizes any one of a number of heating and cooling systems under control of a host computer which directs the heating and cooling systems to heat and cool a reaction-chamber-containing heat exchanger at appropriate times in the process. The reaction chambers are pre-loaded with the nucleic acid(s) to be amplified, a thermostable enzyme to catalyze polymerization, specific oligonucleotide primers, and four different nucleotide triphosphates. Also disclosed is the process for the amplification chain reaction implemented by the machine, which utilizes a thermostable enzyme.

Abstract: An improved liquid handling device used for transferring a selected quantity of liquid from one receptacle to another. The device includes a meniscus tracking feature which minimizes mixing in a liquid sample and contact between the sample and a sample-handling pipette during a liquid-transfer operation. Further included is a volume-correcting feature for improving the accuracy of volume withdrawn into or dispensed from the pipette during a liquid handling operation.

Abstract: An automatic liquid transfer system includes a horizontally translatable table and a vertically translatable set of pipettes. The table accommodates a titer tray having a multiplicity of receptacles to be filled, or holding liquid samples to be diluted, and a rack housing plural rows of disposable tips. During each cycle in a serial dilution process, a fresh set of tips are picked up by the pipettes and used to transfer liquid in a sterile manner from a sample or diluent source to a row of wells in the titer tray, or from one row to a succeeding row of wells where it is mixed with diluent. Thereafter, the tips are discharged back into the rack to maintain sterile conditions during the process. A sensor is provided on the machine to detect whether all of the tips in each set are disengaged and another set successfully picked up.