Method and apparatus for detecting particles, like biological macromolecules or nanoparticles

A detection apparatus being arranged for detecting particles, comprising:

• a separation device having a separation path and a separation force generator, said separation path having a source side in a sample container and a target side in a target container, the separation force generator being arranged for creating a separation force along the separation path for moving the particles along the separation path toward the target side, wherein the target container includes a detection volume and said separation path has an opening end located in the target container;
• a detection device being configured for detecting the particles in the detection volume:
• the detection device including:
• an illumination light source being arranged for providing illumination light,
• a reflecting detection surface being arranged with a fixed distance from the opening end in the target container, said reflecting detection surface restricting the detection volume,
• a sensor camera, and
• an optical system having imaging optics, said imaging optics being arranged as a common-path interferometer for both of directing the illuminating light to the detection volume and the reflecting detection surface and collecting output light from the reflecting detection surface in reflection, the output light comprising both light scattered from the particles in the detection volume and illuminating light reflected from the reflecting detection surface, and the optical system being arranged for directing the output light to the sensor camera;
• and
• an analyzing unit coupled with the detection device and including a computer being configured for analyzing the output light detected by the detection device and for obtaining specific particle features of the particles based on the analyzing of the output light.