Fiber optic chemical sensors based on polymer swelling
AssigneePolysense, Inc.
InventorsWilliam R. Seitz, Marian F. McCurley
Life of this patent
Estimating the term…
Abstract
Chemical sensors can detect the presence of chemical species in solution based upon polymer swelling in response to the chemical species. Polymer swelling is indirectly determined by measuring light reflected from a reflector affixed directly or indirectly to the polymer. Such that increase or decrease in the size of the polymer changes the distance between the reflector and a light source. Measurements of the light reflected from the reflector indicate the amount of swelling or shrinkage of the polymer in response to the chemical species.
Claims30
A detector for quantifying an analyte in a sample comprising:
- (a) a housing
- (b) light transmission means disposed within the housing such that light can be transmitted in both directions through the housing;
- (c) means for coupling a first end of the light transmission means to a light source;
- (d) means for coupling the first end of the light transmission means to a photodetector;
- (e) a reflective member movable between first and second positions with respect to the light transmission means wherein the reflective member is disposed adjacent to a second end of the light transmission means such that light transmitted through the light transmission means from the first end to the second end is reflected by the reflective member and at least partially recollected by the light transmission means and wherein the amount of light recollected depends on the position of the reflective member relative to the light transmission means;
- and
- (f) a polymeric detector element the volume of which varies in response to the amount of analyte in the sample, said detector element being mechanically connected to the reflective member and the light transmission means such that the position of the reflective member relative to light transmission means depends on the volume of the detector element.
A method for detecting an analyte in a sample, comprising
- (a) contacting the sample with a detector comprising a polymeric detector element, the volume of which depends on the amount of the analyte, a light transmission means and a reflector, arranged such that the light transmitted through the light transmission means is reflected by the reflector and recollected by the light transmission means to an extent determined by the volume of the sensing element being in contact with the sample for a period of time sufficient for the sensing element to come to its equilibrium volume;
- (b) introducing light through the light transmission means;
- (c) measuring the intensity of the light reflected and recollected by the light transmission means;
- and
- (d) comparing the reflected intensity with a standard to determine the amount of analyte.
Dependencies are inferred from the claim text.