Disposable self-calibratable electrode package

Claim 1

In a system employing a chemistry analysis machine, for measuring a plurality of distinct characteristics of a body fluid sample or a calibration fluid and having means for receiving electrical signals proportional to each of the characteristics, the improvement separate from the analysis machine including: a replaceable cartridge of a given shape, having a box-like body adapted to be plugged into the analysis machine and to be thus connected for a single use in electrical and mechanical engagement with the analysis machine and to be disconnected after use for replacement with a fresh cartridge, the cartridge including; (a) a fluid flow channel and a plurality of planar ion and gas sensor electrodes in a bank adjacent to the fluid flow channel positioned so as to be contacted by fluid contained in the channel, each electrode being adapted to generate an electrical signal proportional to the respective ion or gas concentration characteristic of the fluid sample, (b) reference electrode disposed in a reference solution well which has a reference fluid channel communicating with the fluid flow channel at a point downstream of the sensor so as to provide a stable liquid junction between the reference electrode and the fluid in the fluid flow channel; (c) first and second containers, the first container containing a calibration liquid with zero head space, of known chemical characteristics, tonometered with gas, and isotonic with relation to blood and the second container containing a reference solution hypertonic with relation to the blood and the calibration liquid; (d) cartridge inlet means adapted to receive a body fluid test sample; (e) a reference flow line establishing fluid communication between the container of reference solution and the reference solution well, said well and said reference flow line being separated from the fluid flow channel by said liquid junction; and (f) means to selectively and repeatedly direct the flow of said tonometered liquid or said body fluid sample over the bank of electrodes, whereby said cartridge is adapted to generate a plurality of electrical signals proportional to the ion or gas concentration of the sample.