An evaluation of the temperature control system of the Centrifichem 400

We evaluate the manufacturer's temperature calibration procedure for the Union Carbide Centrifichem 400 using a procedure developed in our laboratories. We substituted a Yellow Springs, Inc., Model 45 CU Cuvette Thermometer with a thermistor probe for the mercury thermometers. This dramatically shortened the time required for temperature measurements by eliminating the time required for the mercury thermometers to equilibrate. The cuvette temperature measurements with the YSI 45 CU accurately reflect the analyzer equilibrium temperature only when the YSI 45 CU thermistor probe is in the same cuvette as the analyzer thermistor. We also evaluated the accuracy and precision of the temperature control system and the time required to reach thermal equilibrium. We found that temperature equilibration occurs in less than a minute and has a range of less the +/- 0.1 degree C from the mean temperature. Our procedure for monitoring temperature equilibration gave improved accuracy and precision.