An apparatus for analyzing optical properties of a sample includes a housing to receive a light source and a detector; a sample locus defined relative to the housing and positioned such that when a light source and a detector are in predetermined positions, the sample locus is subject to illumination by the light source and the detector is positioned to receive and detect light from the sample; a cover on the housing, the cover being movable in a hinged manner between an open position and a closed position; and a sample-receiving surface for receiving a free-standing sample in liquid or semi-solid form. When the cover is moved to the closed position it encloses the sample locus, with the sample-receiving surface being tilted away from horizontal during the closing movement and the sample being retained thereon by surface tension or adhesion and brought to the sample locus in an enclosed environment.