Instrument and method for automatically heat-sealing a microplate

A system for processing involving pipetting and/or analyzing liquid samples equipped with at least one instrument for automatically heat-sealing a microplate provided with a plurality of open-top wells surrounded by protruding rims, said wells being configured for receiving said reaction mixtures, said instrument comprising:

• a heating device for heating a thermally fixable sealing cover disposed over said microplate adjacent said wells, the sealing cover comprising regions in opposite relationship with respect to said protruding rims, wherein the heating device comprises:
• (a) a plurality of discrete electrically conductive heating elements each individually configured to generate Ohmic heat, the heating elements configured to exclusively contact the sealing cover in said regions;
• and
• (b) a plurality of non-heated zones positioned adjacent to the heating elements and in opposite relationship with respect to the open-top wells of the microplate when said heating device is in thermal communication with said sealing cover;
• a cooling device for actively cooling said microplate;
• and
• a controller configured to control activity of said heating and cooling devices in a manner to heat said sealing cover so as to thermally fix it to said microplate and to actively cool said microplate so as to keep a temperature of said reaction mixtures below a predefined temperature when heating said sealing cover, the controller being configured to exclusively heat the plurality of discrete electrically conductive heating elements so as to thermally fix said regions of said sealing cover to said microplate.