Patent ID: 8858899

Claim:
A fraction collector arrangement comprising a fraction collector arm ( 4 ) and dispensing head ( 5 ) on said arm; a cassette tray ( 10 ); and at least one cassette ( 2 ); said cassette tray including plural predefined cassette holding positions; wherein said at least one cassette includes a plurality of receptacles, said receptacles being arranged at predefined positions in said at least one cassette and the at least one cassette being selectively positionable at one of a plurality of selectable positions with respect to said tray, wherein said cassette and the cassette tray each include complementary magnetic arrangements and mechanical positioners, whereby said cassette is retained at said one selectable position with respect to the tray by said complementary magnetic arrangement and wherein fractions of liquid are sequentially dispensed from said dispensing head into the plurality of receptacles arranged in said cassette, by movement of the dispensing head on the arm and wherein the complementary magnetic arrangement pulls said cassette against said mechanical positioners when said cassette is positioned on the tray.