The presence and concentration of a light absorbing constituent in a fluid medium is determined in-situ by immersing in such medium a probe having a prism at one end whose refractive index is greater than that of the medium and causing light including a wavelength absorbable by such constituent to traverse...http://www.google.fr/patents/US4829186?utm_source=gb-gplus-shareBrevet US4829186 - Methods and apparatus for measuring the light absorbance of a fluid medium
Methods and apparatus for measuring the light absorbance of a fluid medium
