Patent ID: 8383047
Filing Date: 2013-02-26
Classification: A61B,G01N

Abstract:
1. A sensor for measuring the concentration of an assay substance, the sensor comprising an optical fiber which extends longitudinally into a cavity defined by a surrounding wall, the optical fiber having an end portion within the cavity, the end portion terminating in a tip which is provided with an optically active substance which has optical properties which depend on the concentration of the assay substance; wherein the cavity is filled with an encapsulating material which is permeable to the assay substance and which encapsulates the end portion of the optical fiber, and the surrounding wall is provided with at least one flow path for communicating the cavity with a region to be sampled; and wherein the optical fiber includes a glass fiber and an outer buffer layer, a terminating portion of the optical fiber is devoid of the buffer layer, the terminating portion of the optical fiber passes through a gas isolation collar and into the cavity, the gas isolation collar being bonded to the terminating portion of the optical fiber in substantially gas-tight fashion, and the buffer layer terminating short of the gas isolation collar.