Coulometric TCO2 analyses for marine studies; an introduction

摘要: Abstract Progress in the introduction of coulometry for analysis total carbon dioxide (TCO2) marine waters is described. An extractor—stripper removes CO2 that measured coulometrically by quantity electricity (coulombs) used to electrogenerate OH− ions titration acid formed reaction and ethanolamine. The equivalence point detected photometrically with thymolphthalein as indicator, Faraday's Law relates coulombs equivalents titrant generated determined so there are no standard curves needed or titrants standardize store. Accuracy was adding gelatin capsules containing 100–1500 μg C pure CaCO3 into stripper, accuracies better than ± 1 were achieved. best precision natural seawater (± error) 0.5 μmol l−1 found 17 samples Bermuda coastal having a mean TCO2 2007.2 (0.05% CV). Sources error precautions discussed. This method, which has been successfully at sea, can be study variety phenomena involving TCO2.