The invention provides a system for detection of at least one analyte present in a fluid, the system comprising a detector comprising an assay configured to detect presence of the analyte in the fluid, the detector comprising a specimen sampling region for the fluid and a protective seal partially covering the detector, wherein only the specimen sampling region is uncovered by the fluid-protective seal, and wherein the fluid-protective seal provides resistance to acid. The system can be fully submerged in an acidic solution and still retain is functionality.
