Optical osmometer for chemical detection

• US 5,279,793 A
• Filed: 09/01/1992
• Issued: 01/18/1994
• Est. Priority Date: 09/01/1992
• Status: Expired due to Fees

• Current Assignee: Alexander J. Glass
• Original Assignee: Alexander J. Glass
• Inventors: Glass, Alexander J.
• Primary Examiner(s): Johnston, Jill A.
• Application Number:
  US07/938,940
• Time in Patent Office: 504 Days
• Field of Search: 422/82.05-82.08, 422/82.11, 422/82.13, 250/227.14, 385/12, 385/13, 128/634
• US Class Current: 422/82.06
• CPC Class Codes: G01N 13/04 Investigating osmotic effects
• CPC Class Codes: G01N 21/8507 Probe photometers, i.e. with optical measuring part dipped into fluid sample

Abstract

A fiber optic optical osmometer (50) includes a fiber optic probe (20) inserted into a chamber (24) including a filter member (10 ) and a diaphragm (14) responsive to a pressure change in the chamber. The filter member transmits a fluid including an analyte into the chamber. A reagent within the chamber reacts with the analyte to form a reaction product. The filter member retains the reaction product in the chamber creating a pressure change. The diaphragm is illuminated by light directed to it from the fiber optic probe. Light reflected from the diaphragm is returned via the fiber optic probe to a detector and measurement electronics. As the diaphragm responds to pressure changes in the chamber, light returned to the detector is modulated proportional to the pressure change. The pressure change may be interpreted as a measure of the concentration of the analyte in the fluid.

Claims

1. An apparatus for detecting concentration of an analyte in a fluid, comprising:

a chamber having a reagent therein, said chamber including a filter member permeable to the analyte and the fluid;

said filter member for transmitting the fluid and the analyte into said chamber to react with the reagent and form a concentration of a reaction product proportional to the concentration of the analyte in the fluid;

said filter member impermeable to said reaction product for retaining said reaction product therein to cause a pressure change in said chamber, said pressure change related to the concentration of reaction product formed;

said chamber including a pressure sensitive member deformable by said pressure change within said chamber; and

optical means for illuminating said pressure sensitive member and receiving an optical signal reflected therefrom, said optical means arranged such that deformation of said pressure sensitive member modulates said optical signal, whereby measurement of said optical signal modulation provides a means for determining the concentration of the analyte.

2. The apparatus of claim 1 further including means for computing the analyte concentration from said optical signal modulation.

3. The apparatus of claim 1 further including means for determining the temperature of said chamber.

4. The apparatus of claim 1 wherein said filter member is a dialysis fiber.

5. The apparatus of claim 4 wherein said optical means includes a fiber optic element.

6. The apparatus of claim 5 wherein said pressure sensitive member is a diaphragm.

7. The apparatus of claim 6 further including means for measuring the temperature of said chamber.

8. The apparatus of claim 7 further including means for computing the analyte concentration from said optical signal modulation.

9. An apparatus for detecting concentration of an analyte in a fluid, comprising:

first and second cylindrical chambers joined in an end-to-end relationship and generally coaxial, said chambers separated by a diaphragm deformable by a pressure change in said first chamber;

said first chamber having a reagent therein for reacting with the analyte to form a reaction product, and said first chamber having a generally cylindrical wall including a filter member, said filter member permeable to the analyte and the fluid for transmitting the fluid and the analyte into said chamber to react with the reagent and form a concentration of said reaction product proportional to the concentration of the analyte in the fluid, and said filter member impermeable to said reaction product for retaining said reaction product in said first chamber to cause said pressure change therein, said pressure change related to the concentration of reaction product formed;

said second chamber having a substantially cylindrical wall including a semipermeable filter member; and

said second chamber including fiber optic means for illuminating said diaphragm and receiving an optical signal reflected therefrom said fiber optic means arranged such that deformation of said diaphragm modulates said optical signal, whereby measurement of said optical signal modulation provides a means for determining the concentration of the analyte.

10. The apparatus of claim 9 further including means for measuring the temperature of the fluid.

11. The apparatus of claim 9 further including means for detecting said optical signal and means for computing the analyte concentration from said optical signal modulation.

12. An apparatus for detecting the concentration of an analyte in a first fluid, comprising:

first and second cylindrical chamber joined in an end-to-end relationship and generally coaxial, said chambers separated by a diaphragm said diagram having an original shape deformable by a pressure change in said chambers;

said first chamber having a reagent therein for reacting with the analyte to form a reaction product, and said first chamber having a generally cylindrical wall including a semipermeable filter member, said filter member permeable to the analyte and the first fluid for transmitting the first fluid and the analyte into said first chamber to react with the reagent and form a concentration of said reaction product proportional to the concentration of analyte in the fluid, and said filter member impermeable to said reaction product for retaining said reaction product in said first chamber to create a first pressure change therein, said first pressure change related to the concentration of reaction product formed and said first pressure change deforming said diaphragm from said original shape;

said second chamber including fiber optic means for illuminating said diaphragm and receiving an optical signal reflected therefrom, said fiber optic means arranged such that said optical signal changes from a first value to a second value responsive to said deformation of said diaphragm; and

said second chamber including means for receiving a measurable fluid pressure to create a measurable second pressure change in said second chamber, said second pressure change equal to said first pressure change for restoring said diaphragm to said original shape, said original shape restoration detectable by a change in said optical signal from said second value to said first value, whereby measurement of said second pressure change provides a means for determining the concentration of the analyte.