Microfluidic element for analysis of a sample liquid

A microfluidic element for analyzing a fluid sample, said microfluidic element comprising a substrate and a microfluidic transport system having a channel structure, the microfluidic transport system being enclosed by the substrate and a covering layer, wherein

• the channel structure comprises a channel with two side walls, and a chamber which adjoins the channel,
• the channel comprises a channel section and a valve section adjoining the channel section,
• the two side walls run parallel to each other in the channel section,
• the chamber has a chamber wall with an inlet orifice in which area of the chamber wall is greater than area of the inlet orifice in the same plane, and the chamber has a chamber side wall that adjoins the chamber wall,
• the inlet orifice in the chamber wall adjoins the valve section, so that a fluid can flow out of the channel through the inlet orifice of the chamber wall and into the chamber,
• the valve section is provided with a fluid transport cross-section that enlarges in width in a flow direction, wherein in width, the fluid transport cross-section of the valve section at the inlet orifice is larger than a fluid transport cross-section in the channel section at a transition from the channel section to the valve section, and wherein the fluid transport cross-section of the valve section enlarges continuously from the transition to the inlet orifice, and
• an end of the valve section, which has dimensions which differ from the chamber, forms a capillary stop such that a fluid flowing through the channel is stopped at the end of the valve section at the inlet orifice of the chamber, and wherein
• a rib is positioned in the valve section between two valve section side walls such that two adjacent valve section sub-channels are formed, which both end at the chamber wall of the chamber and in which one of the valve section sub-channels is narrower than the other, wherein the distance of the first valve section sub-channel from the second valve section sub-channel at the chamber wall is at least twice the width of the narrower valve section sub-channel.