Handheld electromonitor device

Apparatus for measuring the amount of an analyte in a liquid electrolyte which comprises:

• a housing substantially enclosing a data processing system including a power supply, a microprocessor, and a memory;
• a sensor insertable in the housing and comprising a colloidal gold working electrode, a reference electrode and a counter electrode adapted to be in contact with a sample of said electrolyte;
• an electrical connector adapted to couple signal output from the inserted sensor with the data processing system;
• a microchip positioned outside the housing and containing calibration data interrelating values of said signal output with amounts of said analyte in said electrolyte;
• a microchip reader on the housing operable to transfer calibration data from the microchip to the data processing system;
• circuitry within the housing configured to apply a square wave coulometric analytical technique to the sensor;
• a source of potential within the housing adapted to apply a potential to said circuitry;
• and wherein
• said microprocessor is programmed to apply said potential to said circuitry to measure the signal output from the sensor, and to compare said measured output signal with said calibration data to thereby determine the amount of said analyte in said electrolyte.