A pipette holder that includes: (i) a base; (ii) a recess made in the base, which can removably house a well support; (iii) a pipette support comprising a first housing into which can be inserted a pipette equipped with one or more tubular pipette cones that each comprise a tip intended for pipetting liquid, the first housing opening out onto the recess of the base, the pipette support being translationally mobile relative to the base in a direction parallel to an axis of the pipette cones and mobile between a first position in which the tip of each pipette cone is inserted in a well of the well support and at least one second position in which the tip is outside the well; and (iv) a second housing which can removably house a magnetized part.