A method and a micropipetting apparatus is described for dispensing a
liquid volume into a vessel via pipetting needle without any contact
between the needle and a liquid contained in the vessel. The method
comprises forming a drop at the delivery tip of the pipetting needle, the
drop being retained at the tip by adhesion forces, and ejecting the drop
from the tip of the pipetting needle by focusing at the tip of the
pipetting needle a mechanical excitation wave applied at an excitation
point at some distance from the tip of the pipetting needle. The
apparatus comprises a pipetting needle, an electromechanical transducer
mechanically connected with said pipetting needle for mechanically
exciting the pipetting needle with a pulse of mechanical waves that
propagate through the needle, and an electrical signal generator for
generating an excitation pulse signal and for applying this signal to the
electromechanical transducer.