CALIBRATION OF AN AUTOMATIC INSTRUMENT FOR BICARBONATE MONITORING

The performance of an automatic instrument which allows one to measure discontinously (every 20 minutes) bicarbonate alkalinity (BA) in comp lex organic solutions is evaluated. Bicarbonate concentration is deter mined from overpressure measurements in a sealed vessel where inorgani c carbon is completely converted to carbon dioxide after acidification of the sample. The accuracy of the instrument has been tested as a fu nction of various operating parameters (ratio of overhead ps volume in the vessel over the liquid sample volume, concentration of bicarbonat es and temperature). Error sources were evaluated and operating condit ions which yield satisfactory performance identified.