The opal glass method (OGM) is a standard technique used by the ocean optics community to measure the spectral absorption coefficients of algal suspensions. We present and evaluate this method for its potential application to measurements of the inherent optical properties (optical absorption and scattering coefficients) of dilute mammalian cell suspensions, as an alternative to the integrating sphere method. In a series of controlled experiments on absorbing and scattering phantoms (Evans blue dye and polystyrene spheres 1-20 μm in diameter), separation of absorption and scattering was possible with less than 20% error in absorption coefficient estimates for particles with major scattering components in the size range of 2-5 μm.
A. Sefkow, M. Bree, and M.-A. Mycek, "Method for Measuring Cellular Optical Absorption and Scattering Evaluated Using Dilute Cell Suspension Phantoms," Appl. Spectrosc. 55, 1495-1501 (2001)