Arrangement for measuring the concentration of optically active substances dissolved in a solution

摘要

The invention relates to an arrangement for measuring the concentration of optically active substances, in particular of glucose, dissolved in a solution, polarised light from a light source being passed through the solution located in a cuvette and the arrangement having at least one photodetector receiving a measurement signal as well as a photodetector receiving a reference signal. An essential feature of the invention is that a polarising optical waveguide (6) having at least one Y-junction (5) is provided, into one branch (4) of which waveguide the light from the light source (2) is injected and to the other branch (7) of which waveguide the photodetector (13) receiving the measurement signal is coupled, that a GRIN lens (9) is furthermore provided, with the aid of which the light is extracted from the waveguide (6) at the unbranched end and sent collimated to the cuvette (1), and that, in the transmission direction behind the cuvette (1) a lambda /4 plate (10) and a mirror (11) are arranged one after the other, the mirror (11) being positioned such that the light reflected from the mirror (11) propagates through the lambda /4 plate (10) and the cuvette (1) in the opposite direction, and that the measurement signal emerging from the cuvette (1) is coupled back into the waveguide (6) by means of the GRIN lens (9). <IMAGE>