Method and apparatus for determining the concentration of optically-active materials in a fluid
First Claim
1. In an apparatus for determining the concentration of optically-active substances, by polarimetry, in a carrier medium, the apparatus having a measurement vessel with two separated chambers in which said carrier medium and a reference medium are respectively disposed, to polychromatic light sources which generate respective light beams in respective propagation paths light beams, and means for identifying the concentration of a selected substance in said carrier medium by generating a comparative signal based on the respective resulting polarization arising in said light beams due to interaction with said carrier and reference media, said vessel having side walls which are transmissive for said light beams, the improvement comprising:
- means disposed in the respective propagation paths of said light beams for dispersing said light beams before said light beams are incident on said detector means and for thereby causing substance-dependent interaction of said light beams in said carrier and reference media;
means for identifying the concentration of a selected substance in said carrier medium by generating a comparative signal based on the respective resulting polarization arising in said light beams due to interaction with said carrier and reference media, andstray light detector means disposed on opposite sides of said measurement vessel for detecting stray light from said light beams deflected through said side walls of said measurement vessel by non-absorbing molecules in said carrier medium and for generating an electrical signal corresponding to said stray light for use by said means for identifying the concentration of said selected substance in the generation of said comparative signal to correct said comparative signal dependent on the magnitude of the detected stray light.
0 Assignments
0 Petitions
Accused Products
Abstract
In a method and apparatus for determining the concentration of optically-active substances in a fluid, such as glucose in the body fluids of a patient, two light sources are used to produce respective polarized light beams which pass through the substance to be analyzed and are incident on a detector. The second beam has a fixed polarization direction relative to the first beam. The light sources are alternatingly switched on and off at a known-frequency. A dispersing element is disposed in the path of each beam. A comparative signal is produced from the beams exiting the substance and incident on the detector. Due to the presence of the dispersive element in the path of each beam, it is possible to spectrally resolve the components of the comparative signals, so that the optical polarization contributed to the comparative signal by each substance in the fluid can be identified, and thus the concentration of a selected optically-active substance, even in the presence of multiple optically-active substances in the fluid, can be accurately identified.
-
Citations
19 Claims
-
1. In an apparatus for determining the concentration of optically-active substances, by polarimetry, in a carrier medium, the apparatus having a measurement vessel with two separated chambers in which said carrier medium and a reference medium are respectively disposed, to polychromatic light sources which generate respective light beams in respective propagation paths light beams, and means for identifying the concentration of a selected substance in said carrier medium by generating a comparative signal based on the respective resulting polarization arising in said light beams due to interaction with said carrier and reference media, said vessel having side walls which are transmissive for said light beams, the improvement comprising:
-
means disposed in the respective propagation paths of said light beams for dispersing said light beams before said light beams are incident on said detector means and for thereby causing substance-dependent interaction of said light beams in said carrier and reference media; means for identifying the concentration of a selected substance in said carrier medium by generating a comparative signal based on the respective resulting polarization arising in said light beams due to interaction with said carrier and reference media, and stray light detector means disposed on opposite sides of said measurement vessel for detecting stray light from said light beams deflected through said side walls of said measurement vessel by non-absorbing molecules in said carrier medium and for generating an electrical signal corresponding to said stray light for use by said means for identifying the concentration of said selected substance in the generation of said comparative signal to correct said comparative signal dependent on the magnitude of the detected stray light. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. In a method for determining the concentration of optically-active substances, by polarimetry, in a carrier medium, including the steps of directing respective light beams from two polychromatic light sources in respective propagation paths passing through both a carrier medium and a reference medium respectively contained in separate chambers of a measurement vessel having side walls which are transmissive for said light beams and wherein said respective light beams interact with said carrier and reference media such that polarization occurs, detecting said light beams upon emerging from said chambers and generating electrical signals corresponding to characteristics of said light beams, and means for identifying the concentration of a selected substance in said carrier medium by generating a comparative signal based on a respective resulting polarization arising in said light beams due to interaction with said carrier and reference media, the improvement comprising:
-
passing said light beams through a dispersing element for dispersing said light beams before said light beams are incident on said detector means; identifying the concentration of a selected substance in said carrier medium by generating a comparative signal based on a respective resulting polarization arising in said light beams due to interaction with said carrier and reference media; and detecting stray light from said light beams deflected through said walls of said measurement vessel by non-absorbing molecules in said carrier medium and generating an electrical signal corresponding to said stray light for use for identifying the concentration of said selected substance in the generation of said comparative signal by correcting said Comparative signal dependent on the magnitude of the detected stray light. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
-
Specification