Improvements in a fast potentiometric seawater alkalinity determination

• Main Authors: Pérez, Fiz F., Ríos, Aida F., Rellán, Trinidad, Álvarez, Marta
• Format: Article in Journal/Newspaper
• Language: Spanish; English
• Published: Universidad Autónoma de Baja California 2000
• Subjects: PH; Alkalinity; Potentiometry; Seawater; Carbon dioxide; Referencia; North Atlantic Deep Water; North Atlantic
• Online Access: http://hdl.handle.net/10261/56954

19 páginas, 12 figuras, 1 tabla During the Cither 3 cruise along WOCE section A14, where 107 full-water column stations were surveyed, pH and alkalinity were measured potentiometrically. Corrections carried out on the raw data set have allowed us to improve the data quality. The correction procedure was focused on monitoring: (i) calibrations, (ii) liquid junction potential and (iii) seawater sub-standards; CO2 reference material (CRM) has been used to check this procedure. Accuracy of pH15 measurements (NBS scale) and alkalinity was 0.004 and 1.4 μmol.kg–1, respectively. Certified total inorganic carbon on CRM, batch 24, is 1987.55 μmol.kg.–1. A value of 1987.8 ± 2.2 μmol.kg–1 was obtained following the correction procedure. This improvement was independently verified by means of the covariances between nitrate and pH, and between silicate and normalized alkalinity in North Atlantic Deep Water. This work was supported by CICYT (grant number ANT94-1168-E) and IFREMER (University contract number 94-1430-087). Peer reviewed