Optical measurement system for determination of transmitted and scattered radiation

An optical measurement system for determination of transmitted and scattered radiation of a liquid sample contained in a capillary and subject to measurement radiation, said measurement radiation having an optical axis being essentially at a right angle to a central axis of said capillary, comprising a first detector being provided for picking up transmitted radiation, which is positioned close to or on said optical axis of said measurement radiation, and a second detector defining an optical axis and being provided for picking up scattered radiation, which is placed at a distance from said first detector in a direction of said central capillary axis, wherein said first detector and said second detector are positioned on different sides of a plane ε, which contains said central capillary axis and is at a right angle with said optical axis of said measurement radiation wherein said capillary is placed in a bore of a measurement block and is provided with at least one optical separating element between an input region of said measurement radiation and an output region of said scattered radiation, wherein said separating element covers an annular gap between said capillary and the wall of said bore.