ISO 9964-2:1993

Overview

ISO 9964-2:1993 is an international standard published by ISO, detailing the method to determine potassium concentration in water samples using atomic absorption spectrometry (AAS). This standard is part of a series dedicated to water quality assessment-specifically focusing on the measurement of sodium and potassium ions. The method described applies to raw and drinking water with potassium levels typically ranging from 5 mg/l to 50 mg/l, with flexibility for extension through sample dilution.

The technique involves adding a caesium chloride solution to suppress ionization, followed by direct aspiration of the sample into an air/acetylene-flame atomic absorption spectrometer. The absorbance is measured at a wavelength of 766.5 nm, providing a reliable and precise means of determining dissolved potassium content.

Key Topics

• Scope and Range: Applicable to raw and drinking water samples containing 5 mg/l to 50 mg/l of potassium, with potential for broader application if samples are diluted accordingly.
• Principle of Method: Utilizes caesium chloride as an ionization suppressant and flame atomic absorption spectrometry for detection and quantification.
• Sample Preparation: Includes guidelines for filtering particulate matter, using appropriate reagents of analytical grade, and ensuring consistency in sample and solution preparation.
• Calibration: Describes the preparation of calibration solutions and the construction of calibration curves critical for accurate determination.
• Interferences: Standard acknowledges the minimal interference from common ions in water, contributing to the robustness of the method.
• Apparatus Requirements: Specifies the need for a compatible atomic absorption spectrometer, appropriate glassware, and stringent cleaning protocols to prevent cross-contamination.
• Reporting: Outlines requirements for reporting results, including identification of samples, adherence to the method, and documentation of any deviations.

Applications

ISO 9964-2:1993 is widely used in the following contexts:

• Drinking Water Quality Control: Ensures public health by monitoring potassium levels, which is critical for compliance with regulatory standards.
• Environmental Monitoring: Applied in the assessment of water bodies to detect potential contamination or natural variations in potassium content.
• Water Treatment Facilities: Utilized to evaluate the effectiveness of treatment processes and to monitor water chemistry before and after processing.
• Research Laboratories: Provides a standard methodology for academic and industrial research focused on water chemistry and environmental science.
• Regulatory Compliance: Supports water suppliers and regulatory agencies in meeting analytical quality standards for routine water analysis.

Related Standards

For comprehensive water quality assessment and analytical best practices, the following related ISO standards are relevant:

• ISO 9964-1:1992: Water quality - Determination of sodium by atomic absorption spectrometry.
• ISO 9964-3:1996: Water quality - Determination of sodium and potassium by flame emission spectrometry.
• ISO 5667-1:1980: Water quality - Sampling - Guidance on the design of sampling programmes.
• ISO 5667-2:1991: Water quality - Sampling - Guidance on sampling techniques.

Practical Value

Adherence to ISO 9964-2:1993 ensures:

• Consistency and Reliability: Laboratories worldwide achieve comparable results in potassium determination.
• Data Quality Improvement: Reduces analytical errors through stringent calibration and sample handling protocols.
• Regulatory Confidence: Facilitates acceptance of results by regulatory authorities and customers by employing recognized standards.

By following this ISO guideline, organizations and laboratories can confidently report water potassium concentrations, contributing to safer drinking water and effective environmental management.