Coulometric TCO2 analyses for marine studies; an introduction

A system was developed and tested for stripping total carbon dioxide from large volumes of seawater. The carbon dioxide was measured coulometrically by the quantity of electricity used to generate hydroxide ions for the titration of the acid formed by the reaction of carbon dioxide and ethanolamine. The equivalence point was detected photometrically with thymolphthalein as the indicator and Faraday's law related coulombs to equivalent of titrant generated and carbon dioxide determined. Accuracy was determined by adding pure calcium carbonate into the stripper. Sources of error were identified and precautions discussed. Field studies were used to demonstrate the efficiency of the method, which showed potential for a variety of marine carbon dioxide studies including carbon metabolism, water mass movement, analytical calibration and anthropogenic effects. Thirty nine references are included.