Apparatus for robotically performing sanger dideoxynucleotide DNA sequencing reactions using controlled pipet

A robotic system for automatically performing DNA sequencing, comprising:

• a robot having an arm mounted for motion in vertical and horizontal planes;
• a hand for said robot arm having means for pipetting a fluid from a microtiter plate well;
• a microtiter plate having a well formed therein, said well having a bottom, a reagent solution contained in said well;
• a plurality of work surfaces, each having means for supporting a microtiter plate;
• a plurality of reservoirs, each having means for holding a reagent;
• first storage means for storing microtiter plates;
• sensing means for generating a signal in response to said pipetting means making contact with said microtiter plate well bottom;
• and
• a programmable controller having (i) first logic means for instructing said robot to move said pipetting means toward said microtiter plate well bottom by a series of discrete incremental movements, each of said discrete incremental movements in said series being separated by a finite period of time, said series of incremental movements including a set of incremental movements in which each discrete incremental movement is successively smaller than each previous discrete incremental movement in said set, and (ii) second logic means for determining whether said pipetting means has made contact with said microtiter plate well bottom based on said signal from said sensing means during said finite period of time between each of said discrete incremental movements in said set of movements.