| 摘要 |
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. |
