Abstract: A method of identifying and arranging test tubes, which includes providing a rack having an array of wells located at the intersection of mutually perpendicular columns and rows. The columns and rows are aligned on perpendicular edges of the rack. The test tubes are positioned in the wells and then marked with indicia to correspond to the location of the respective wells.

Abstract: A closure device is provided which includes a flexible cover with an array of protruding hollow caps which are formed integrally with and depend from the cover. The caps have cup shaped noses with cylindrical side walls joined to the cover by inwardly tapered intermediate wall sections. The caps form a friction fit with an array of mutually spaced receptacles, for example test tubes, deep well blocks or microwell plates.

Abstract: A pipettor including a body portion, a cylinder having an interior channel, and a filter plug disposed within the channel is disclosed. The filter plug may include a plurality of pores and may preferably be treated with a first chemical, so as to affect closure of the pores when the filter plug contacts a pipetted fluid. The pore closure helps contain leakage of the fluid into the pipettor by sealing the pipettor to additional fluid flow. The filter plug may also be treated with a second chemical to affect a change in the color of the filter plug upon contact with the pipetted fluid. The color change acts as a signal to an operator that possible contamination of the pipettor has occured. The color change and/or closure may also be affected by an aerosol generated from the pipetted fluid.

Abstract: A pipette tip with a volume capacity of at least about 1250 .mu.l that can be used with single channel or multichannel pippetors and that can be used effectively with microtiter tubes, test tubes and microtiter plates. The tip can be a single contiguous piece, typically formed of a material such as polypropylene. The total length of the pipette tip is about 4.0 inches. The tip includes a stem, a head and a midsection disposed between the stem and the head. The tip also includes a passageway that extends longitudinally through the head, the midsection and the stem.

Abstract: A pipetting system having a plurality of fittings whose spacing can be individually adjusted by sliding the fittings along a track. Changing the spacing is accomplished by releasing a clamping plate which secures the fittings to the track. The fittings are then slid into the desired position and reclamped. In addition, there is a stripper mechanism for removing disposable tips attached to the fittings. The release mechanism can be operated in any positioning of the fittings. The mechanism is trigger actuated.

Abstract: A computer controlled pipetting system with a hand held pipettor and a control assembly. The pipettor has a motor driven pump for aspirating and dispensing liquid through a pipette which is inserted to the pipettor. The control assembly has a keyboard for controlling operation of the pipetting system. A calibration pipette is inserted into the pipettor for establishing reference signals corresponding to a selected density and temperature of a liquid which is aspirated into the calibration pipette by the pump. The reference signals are stored in a memory and subsequently used for aspirating selected quantities of liquid into a laboratory pipette which is inserted into the pipettor in place of the calibration pipette.