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Spectrophotometric determination of pH and alkalinity in seawater using pH indicator dyes.

Research Project

Project/Area Number 05554014
Research Category

Grant-in-Aid for Developmental Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field 地球化学
Research InstitutionHokkaido University

Principal Investigator

TSUNOGAI Shizuo  Hokkaido University, Graduate School of Environmental Earth Science Professor, 大学院・地球環境科学研究科, 教授 (00001587)

Co-Investigator(Kenkyū-buntansha) WATANABE Shuichi  Hokkaido University, Graduate School of Environmental Earth Science Instructor, 大学院・地球環境科学研究科, 助手 (00167131)
Project Period (FY) 1993 – 1994
Project Status Completed (Fiscal Year 1994)
Budget Amount *help
¥11,200,000 (Direct Cost: ¥11,200,000)
Fiscal Year 1994: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1993: ¥9,400,000 (Direct Cost: ¥9,400,000)
KeywordsSeawater / pH / Spectrophotometory / Carbon Dioxide / Alkalinity / pH Indicator / Dissolved Inorganic Carbon / Precise Determination of pH / 溶存炭素 / pH指示薬
Research Abstract

In the study of the oceanic carbon system, the precise determination of pH is essentially necessary. The method using a pH electrode is insufficient for the purpose. We have considered to use a dye method for the pH measurement. Recent development in the spectrophotometer makes possible the application. We have made further improvement for the spectrophotometer system. The system can measure the adsorbance curve within 2.5 sec. with an accuracy of 0.0001 of absorbance. Using the system and seawater sample of 70ml, we have the precision of <plus-minus>0.001 pH unit. The method have been successfully applied to the actual seawater samples on board the research vessel, Hakuho Maru in 1994-199
Alkalinity determination is improved by combining a single-step titration and the spectrophotometric pH determination using Bromophenol Blue. We have the precision of <plus-minus>0.001mue

Report

(3 results)
  • 1994 Annual Research Report   Final Research Report Summary
  • 1993 Annual Research Report

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Published: 1993-04-01   Modified: 2016-04-21  

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