Electrochemical sensor devices are provided, in various amperometric, potentiometric, and conductometric sensor device configurations. An amperometric sensor device may include a structural body which has at least one reservoir that has at least one opening; a working electrode located within the reservoir; analyte sensor chemistry located within the reservoir and deposited on at least the working electrode; an auxiliary electrode located outside of the reservoir; a reference electrode; at least one reservoir cap closing the opening to isolate the working electrode and analyte sensor chemistry within the reservoir and to prevent an analyte outside of the reservoir from contacting the analyte sensor chemistry; and means for rupturing or displacing the reservoir cap to permit the analyte from outside of the reservoir to contact the analyte sensor chemistry.