Patent ID: 8858692

Claim:
A filter system comprising: a housing; a filter medium disposed within the housing; an optical analyte sensor characterized by a first region that exhibits a first response to an analyte of interest and a second region that exhibits a second, different, response to an analyte of interest, the optical analyte sensor comprising a detection medium and disposed within the housing such that the detection medium is in fluid communication with the filter medium; and an optical reader comprising a first assembly comprising at least one light source and at least one detector and a second assembly comprising at least one light source and at least one detector; wherein the optical reader is attached to the housing such that at least a portion of light emitted by at least one light source of the first assembly is reflected from the first region of the optical analyte sensor and captured by at least one detector of the first assembly, and at least a portion of light emitted by at least one light source of the second assembly is reflected from the second region of the optical analyte sensor and captured by at least one detector of the second assembly; and, wherein each of the first and second assemblies comprises first and second light sources and a detector disposed between the first and second light sources and wherein the first and second light sources are characterized by different spectral profiles.