Nozzle and method for flow cytometry

A nozzle for a flow cytometer having a housing, whose internal cross-section tapers along its longitudinal axis from its second end to an outlet at its first end, and in which, for a core flow liquid, a feed tube having a circular internal cross-section is arranged, which has an inlet opening, and that discharges into an outlet opening arranged at its first end at a distance from the outlet, wherein an inlet for a sheath flow liquid is arranged at the housing, wherein the housing has an inner wall that is rotationally symmetric to its longitudinal axis, wherein a leading element, which has a first end section, which is arranged in a tapered section of the housing and the edges of which run at a distance from the inner wall of the housing, wherein the leading element extends along the longitudinal axis to a larger degree along a first dimension perpendicular to and intersecting the longitudinal axis up to a distance to the inner wall of the housing than it extends in a second dimension that is perpendicular to and intersecting the longitudinal axis and the first dimension, wherein the leading element extends from its first end, which lies in the plane of the first end of the feed tube or is offset by a distance from the first end of the feed tube, up to its second end, which is arranged at a distance from the second end of the housing, wherein the leading element at its first end has a first end section and a second end section opposite the first end and adjacent to it, which is tapered towards the second end of the leading element opposite the first end in its first dimension, wherein the leading element has its largest extension in the first dimension between the first and the second end section.