Abstract: A single-use sensing device for a clinical chemistry analyzer system includes a carrier which supports a capillary passage. Species selective sensors are located within a test chamber portion of the capillary passage. A rotatable multichamber reservoir having a calibrant chamber for holding calibrant fluid and a sample chamber for containing a sample fluid is rotated first to a calibrant test position and then to a sample test position. In the calibrant test position, the calibrant chamber is connected to the inlet end of the capillary passage to draw calibrant fluid into the test chamber. In the sample test position, the sample chamber is connected to the inlet end to draw sample fluid into the test chamber and purge the calibrant fluid from the test chamber. A set of sensor readings are taken at each position, and concentration values are derived from the two sets of readings.

Abstract: An ion selective electrode includes a conductive electrode body which is supported by an insulating substrate. A convex dome-shaped membrane containing an electroactive species is deposited over and is directly in contact with the electrode body and a surface of the substrate surrounding the electrode body. The membrane has its greatest height above the electrode body and slopes down to meet the surface of the substrate. A moat formed in the insulating substrate surrounds the space from the electrode body to define the outer boundary of the dome-shaped member.