Abstract: A sampler (10), in particular for use in testing the dissolution behavior of pharmaceutical products, wherein the sampler (10) comprises: a vial holder (20) for accommodating a plurality of vials (22a, 22b); a sampling needle assembly (30) with a plurality of sampling needles, wherein the sampling needle assembly (30) and the vial holder (20) may be moved relative to one another in such a way that the sampling needles of the sampling needle assembly (30) may be inserted into the vials of the vial holder (20); and a pump unit (40) with a plurality of diaphragm pumps (42a, 42b) which are designed to convey a fluid via the sampling needle assembly to the vials in the vial holder (20) and to withdraw a fluid therefrom.