Microcomputer-controlled remote pipetter: design and evaluation of a prototype system

A prototype remote pipetter has been designed and evaluated. The principle of operation for the pipetter is the displacement of liquid via a calibrated, screw-driven plunger. Variably sized aliquots of 1 to 1000 μ1 can be delivered. A stepping motor is used to move the plunger, and its position is verified with a linear variable differential transformer. The unit is controlled by a microcomputer. Besides the required operation sequences and error checking, a self calibration check has been designed into the software. Accuracy and precision of plunger movements corresponding to delivery of aliquots ranging from 100 to 500 μ1 are 0.3 μ1 and 0.4 μ1 respectively. Nonlinearity over the full range of plunger travel is 0.02%