Abstract: An apparatus for introducing a specimen into a flow cytometer comprises: a syringe having a hollow barrel containing the specimen, a plunger partially within the barrel and a needle that extends into a volume of a nozzle of the flow cytometer; a one-way port in the nozzle forming a seal against the needle; a mounting platform coupled to both the syringe and to the flow cytometer; and a syringe pump coupled to the plunger, the syringe pump comprising a motor, a drive mechanism coupled to the motor; and a clamping mechanism coupled to the drive mechanism, wherein the motor operates the drive mechanism so as to cause the clamping mechanism to depress the plunger into the barrel.