ISO 22719:2008

Overview

ISO 22719:2008 - Water quality - Determination of total alkalinity in sea water using high precision potentiometric titration - is an international standard developed by ISO. This standard specifies an open-cell potentiometric titration method for the determination of total alkalinity in sea water. The results are expressed in moles per kilogram of sea water. Designed for high-precision and accuracy, the method is suitable for normal sea water samples with practical salinity ranging from 30 to 40 and typical oceanic levels of total alkalinity (2,000 µmol/kg to 2,500 µmol/kg).

The accurate determination of total alkalinity is fundamental for monitoring oceanic carbonate systems, supporting climate research, marine chemistry studies, environmental monitoring, and broader water quality assessments.

Key Topics

• Open-cell potentiometric titration: The standard describes a two-stage titration procedure using hydrochloric acid and sodium chloride to maintain ionic strength, measured via pH glass-reference electrodes.
• Sample preparation and handling: Includes guidelines for sea water sampling, storage, and preparation to maintain sample integrity.
• Apparatus and reagents: Details the required laboratory and, where appropriate, shipboard equipment, including calibrated balances, burettes, titration cells, pH meters, and specific reagent preparations.
• Data collection and calculation: Outlines procedures for recording titrant volume, electromotive force (EMF), and temperature at each point, with data processing involving non-linear least-squares fitting to correct for sulfate and fluoride reactions.
• Quality assurance: Provides recommendations for calibrating instruments, handling reference materials, and ensuring reproducibility and traceability of results.
• Expression of results: Specifies how final alkalinity values should be reported and provides example calculations for clarity and consistency.

Applications

Implementing ISO 22719:2008 offers significant value across various sectors:

• Marine science and oceanography: Provides a standardized, high-precision approach to measure total alkalinity, a critical parameter for studying the marine carbonate system, ocean acidification, and global carbon cycles.
• Water quality monitoring: Supports regulatory compliance and environmental monitoring programs by ensuring consistent and accurate assessment of sea water alkalinity.
• Climate research: Supplies robust, comparable data sets for modeling CO2 absorption in oceans, crucial for understanding and forecasting climate change impacts.
• Industrial and environmental laboratories: Enables laboratories to generate reliable, traceable alkalinity data in support of certification, research, or regulatory activities.
• Reference material development: Facilitates production and validation of certified reference materials for alkalinity in sea water, enhancing quality control processes.

Related Standards

When applying ISO 22719:2008, it is useful to consult several related ISO standards that support the methodology and quality assurance:

• ISO 5667-1: Water quality - Sampling - Part 1: Guidance on the design of sampling programmes and sampling techniques
• ISO 758: Liquid chemical products for industrial use - Determination of density at 20 °C
• ISO 3696: Water for analytical laboratory use - Specification and test methods
• ISO 8466-1: Water quality - Calibration and evaluation of analytical methods and estimation of performance characteristics

Together, these standards help ensure precise sampling, analytical reliability, and robust data for total alkalinity determinations in sea water.

Keywords: ISO 22719, sea water alkalinity, potentiometric titration, water quality standards, ocean alkalinity, marine chemistry, ISO water analysis, environmental monitoring, total alkalinity determination