Abstract: A self-calibrating hybrid spectrophotometer comprises a receptacle for receiving the cuvette, first and second optodes that are configured to permit light to enter the cuvette, third and fourth optodes that are configured to permit light to leave the cuvette, and a controller that is configured to control delivery of light to one of the first and second optodes. Light entering one of the first and second optodes is received at the third and fourth optodes after having interacted with the turbid sample along different paths having different lengths. Measurements made at the third and fourth optodes in response to having illuminated both the first and second source optodes provide two slopes of optical transmittance as a function of path length. The spectrophotometer uses these slopes to identify a slope that is indicative of the absorption coefficient and the reduced scattering coefficient of the sample.

Abstract: An apparatus for earning out near-infrared spectroscopy using intensity-modulated near-infrared radiation or pulsed near-infrared radiation includes sources and detectors. For each source, there exists first and second distances. The first distance is a distance between the source and a first detector. The second distance is a distance between the source and the second detector. For each source, the difference between these two distances is the same. Additionally, wherein, for each source, the detector at a shorter distance is the same detector that is at a longer distance for the other source. A processor derives, from signals received by the detectors, a parameter indicative of two matched slopes. Tins parameter is either phase of the intensity-modulated near-infrared radiation or mean time-of-flight data for the pulsed near-infrared radiation. The processor then provides output data based on an average of the matched slopes.