1. A sampling device adapted to be used in a system for the assessment of the number of particles in a liquid analyte material, the sampling device comprising a sample compartment including an exposing domain, said exposing domain allowing electromagnetic signals from a sample in the exposing domain to pass to a detection device so as to form spatial image of the exposing domain on the detection device, only one inlet through which a volume of a liquid sample representing the analyte material can be introduced, and having no sample outlet, a flow system having at least a channel allowing at least a portion of the volume of the liquid sample to flow within the sampling device, wherein at least a part of the channel through which the sample flows before entering the sample compartment has a plurality of bends or obstructions resulting in substantial turbulent flow in liquid passing the bends or obstructions, and said sampling device being configured to position said exposing domain in relation to said detection device to provide an assessment of said at least one particle parameter of the liquid analyte material, the device having data concerning dimensions of the device which influence the volume of the exposing domain, the data being readable by the detection device or another device adapted to read the data.