Method and apparatus for optically measuring concentration of an analyte

A method for measuring the concentration of an analyte in a medium, comprising the steps of:

• providing a reagent whose optical properties change in response to the concentrations of said analyte;
• exposing said reagent to said analyte in said medium;
• directing a beam of radiant energy along an optical path into said reagent at a wavelength selected to affect said beam of radiant energy as a function of the concentration of said analyte;
• periodically directing a perturbing pulse of energy into said reagent to alter in a controlled manner both the concentration of said analyte along said path and the optical spectral characteristics of said reagents as a function of the concentration of said analyte;
• detecting the effect of said reagent on said beam of radiant energy while the response is changing due to the influence of the perturbing pulse, after the perturbing pulse starts or ends or both;
• determining the time rate of change of said effect;
• and
• correlating said time rate of change to the concentration of said analyte.

Apparatus for measuring the concentration of an analyte in a medium, comprising:

• means for directing a beam of radiant energy along an optical path into said medium at a first wavelength selected to cause a response of said analyte;
• means for periodically directing a perturbing pulse of energy into said medium and for altering in a controlled manner the concentration of said analyte along said path and thereby the response of said analyte to said beam of radiant energy;
• means for detecting the time rate of change of the intensity of radiation leaving said medium as the response of said analyte to said beam of radiant energy while the response is changing due to the influence of the perturbing pulse, after the perturbing pulse starts or ends or both;
• and
• means for correlating said time rate of change to the concentration of said analyte.

Apparatus for measuring the concentration of an analyte in a medium, comprising:

• a sensor element including a reagent whose optical properties change in response to the concentration of said analyte;
• means for exposing said reagent to said analyte in said medium;
• means for directing a beam of radiant energy along an optical path into said reagent at a wavelength selected to affect said beam of radiant energy as a function of the concentration of said analyte;
• means for periodically directing a perturbing pulse of energy into said reagent and for altering in a controlled manner both concentration of said analyte along said path and the optical spectral characteristics of said reagent as a function of the concentration of said analyte;
• means for detecting the time rate of change of the intensity of radiation leaving said reagent as the effect of said reagent on said beam of radiant energy while said effect is changing due to the influence of the perturbing pulse, after the perturbing pulse starts or ends or both;
• and
• means for correlating said time rate of change to the concentration of said analyte.