An Automated Procedure for Laboratory and Shipboard Spectrophotometric Measurements of Seawater Alkalinity: Continuously Monitored Single-step Acid Additions

Authors

Xuewu Liu, University of South FloridaFollow
Robert H. Byrne, University of South FloridaFollow
Michael Lindemuth, University of South Florida
Regina Easley, University of South Florida
Jeremy T. Mathis, Pacific Marine Environmental Laboratory

Document Type

Article

Publication Date

2015

Keywords

Alkalinity, Seawater, Spectrophotometry, Indicator, CO2 system, Ocean acidification

Digital Object Identifier (DOI)

https://doi.org/10.1016/j.marchem.2015.06.008

Abstract

Building on the spectrophotometric procedure of Yao and Byrne (1998), an automated analysis system has been developed for laboratory and shipboard measurements of total alkalinity at a rate of 6 samples per hour. The system is based on single-point hydrochloric acid (HCl) titrations of seawater samples of a known volume with bromocresol purple as an indicator. The titration is continuously monitored using visible spectroscopy to guide the titration rate according to the real-time pH of the samples. Each titration is terminated just below the equivalence point to achieve a precision and accuracy near 1 μmol kg⁻¹.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Marine Chemistry, v. 174, p. 141-146

Scholar Commons Citation

Liu, Xuewu; Byrne, Robert H.; Lindemuth, Michael; Easley, Regina; and Mathis, Jeremy T., "An Automated Procedure for Laboratory and Shipboard Spectrophotometric Measurements of Seawater Alkalinity: Continuously Monitored Single-step Acid Additions" (2015). Marine Science Faculty Publications. 1780.
https://digitalcommons.usf.edu/msc_facpub/1780