FREMGANGSMADE OG APPARAT TIL SEPARATION AF BAKTERIER

摘要

In a method of separating bacteria from a bacteria containing liquid sample by means of a dish-like centrifuge container (21) having an upper opening (25) defined by a radially inwardly extending rim portion (24), the following sequential steps are carried out. The centrifuge container is rotated at a high rotational speed. A volume of a high density component of a density higher than the density of the bacteria is introduced into the centrifuge container, whereupon a volume of a low density component having a density lower than the density of the bacteria is introduced into the container so that a two component gradient separation layer (60) comprising a high density layer (61) and a low density layer (62) is formed within the centrifuge container (21). The liquid sample is introduced through a supply tube (32) into the center of the centrifuge container, and owing to the centrifugal force generated by the rotation of the centrifuge container, the liquid is thrown outwardly from the center of the centrifuge container. The bacteria are forced into the low density component layer (62) and deposited in the interface (63) between the two layers (61) and (62), while the liquid sample is discharged (66) from the upper opening of the centrifuge container through a notch (26). A flushing agent is introduced into the centrifuge container and discharged from the upper opening thereof together with any material adhering at the peripheral surface of the gradient separation layer (60). The centrifuge container (21) is decelerated to a low rotational speed, whereafter a suction pipette (40) is activated and moved from a first position having its tip remote from the inner surface of the peripheral wall of the centrifuge container (21) to a second position having its tip arranged adjacent to said inner surface, while a volume of a transfer liquid is introduced into the centrifuge container so that liquid substance included in the centrifuge container is sucked off therefrom through the pipette tube (41) of the suction pipette (40).