Apparatus and methods for parallel processing of multiple reaction mixtures

Apparatus for parallel processing of multiple reaction mixtures, said apparatus comprising a reactor having an exterior surface, one or more vessels in the reactor for holding said reaction mixtures, each vessel having a central longitudinal axis, a cannula having a longitudinal axis, a distal end, and a port generally adjacent said distal end for transfer of said reaction material to or from the cannula, one or more cannula passages in the reactor extending between said exterior surface of the reactor and said one or more vessels, the one or more cannula passages being adapted for insertion of the cannula through a selected cannula passage and into a respective vessel, and for withdrawal of the cannula from the selected cannula passage and respective vessel, and a sealing mechanism in each cannula passage for sealing against leakage of gas therepast when the cannula is inserted into or withdrawn from the selected cannula passage, wherein said sealing mechanism comprises a valve movable between a closed position for closing the cannula passage and an open position permitting movement of the cannula past the valve, and a seal in the passage sealingly engageable with the cannula when the valve is in its open position.