Abstract: Improved method for the pick up and delivery of a liquid test sample and diluent therefore by a single syringe having a syringe valve for placing the syringe barrel in fluid connection with either a diluent pick up line or a sample pick-up line. The method is comprised essentially of the steps of priming the apparatus, picking up the diluent through the diluent pick-up line and thereafter with a continuing downward stroke of the syringe plunger picking up a percentage volume of liquid sample. Preferably, an air bubble is picked up in the end of the sample pick-up line before the sample pick-up cycle. After the full downward stroke of the syringe plunger, the diluted sample is delivered by depressing the plunger to its zero volume setting.An apparatus is provided having a computer controlled syringe plunger drive which includes a zero volume switch, and a computer controlled syringe valve having branch ports adapted to be connected to a diluent and a sample pick-up line.