Spectroscopic method to determine absolute concentration of substance

摘要

A spectroscopic method of determining the absolute concentration of a material whose absorption coefficient is known is used when the material is one of the constituents of a sample of a translucent substance, e.g. biological tissue whose spectroscopic qualities are unknown. Firstly, the sample's reflection characteristic and its extinction coefficient are measured. A filter medium whose extinction and scatter coefficients are known e.g. a fibre-optic cable is then interposed in the spectrometer lightpath and a characteristic optical parameter for the combination obtained. From the variables so measured an accurate determination of the required concentration is derived using an algebraic identity based on Kubelka-Munck theory.