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Control samples for the determination of pH in low ionic strength waters: consensus values from interlaboratory tests
M J Gardner1, J E Ravenscroft, C Ackers
1WRC, Henley Road Medmenham, Marlow SL7 2HD, UK.
Talanta
|January 1, 1997
Summary
Interlaboratory tests reveal challenges in pH determination for low ionic strength waters. New quality control materials are proposed to improve accuracy by addressing atmospheric carbon dioxide effects.
Area of Science:
- Environmental Science
- Analytical Chemistry
Background:
- Accurate pH determination is crucial for environmental monitoring.
- Low ionic strength waters present unique challenges for standard pH measurement techniques.
- Existing quality control materials may not adequately represent real-world conditions.
Purpose of the Study:
- To report on interlaboratory tests using low ionic strength buffer solutions.
- To provide data for developing more realistic quality control materials for pH determination.
- To discuss the impact of atmospheric carbon dioxide on pH measurements.
Main Methods:
- Conducting a series of interlaboratory tests.
- Analyzing test data and background information.
- Evaluating the effect of atmospheric carbon dioxide.
Main Results:
- Interlaboratory tests highlighted variability in pH measurements.
- Atmospheric carbon dioxide significantly affects the pH of low ionic strength reference samples.
- Specific control samples demonstrated suitability for routine use.
Conclusions:
- Development of improved quality control materials is necessary for accurate pH determination in low ionic strength waters.
- Routine use of recommended control samples can enhance measurement reliability.
- Understanding and mitigating CO2 interference is key for precise environmental pH monitoring.
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