A receptacle having a plurality of interconnected chambers arranged to permit multiple process steps or processes to be performed independently or simultaneously. The receptacles are manufactured to separate liquid from dried reagents and to maintain the stability of the dried reagents. An immiscible liquid, such as an oil, is included to control loading of process materials, facilitate mixing and reconstitution of dried reagents, limit
evaporation, control heating of reaction materials, concentrate
solid support materials to prevent clogging of fluid connections, provide minimum volumes for fluid transfers, and to prevent process materials from sticking to chamber surfaces. The receptacles can be adapted for use in systems having a
processing instrument that includes an
actuator system for selectively moving fluid substances between chambers and a
detector. The
actuator system can be arranged to concentrate an
analyte present in a sample. The
detector can be used to detect an optical
signal emitted by the contents of the receptacle.