Abstract: A probe head used in robotic assays for transferring liquid in miniscule quantities. The probe head includes an array of liquid transferring needles which move as a unit with the probe head. As the needles contact a surface, high spots or other irregularities on the surface are accommodated by needle compliance to assure all needles ultimately touch the surface. Touching contact assures reliable liquid transfer.

Abstract: A releasably attachable manual dispensing aid is operable with a syringe having a syringe body and a syringe plunger that is movable within the syringe body. The dispensing aid includes a dispensing aid body that is releasably attachable to the syringe body. The dispensing aid further includes a dispensing aid plunger that is attachable to the syringe plunger, and has a slide that is slidable within the dispensing aid body. A fine adjustment, bottom stop, Chaney stop, and/or drag brake for the slide are optionally provided. An electronic linear position measuring device has a first portion fixed to the dispensing aid body and a second portion fixed to the dispensing aid plunger. Optionally, the dispensing aid includes a microprocessor that receives as inputs a calibration value for a particular syringe and the position signal, and determines as an output signal the true volume of liquid displaced by the syringe plunger movement.