Overview
ISO 739:1976 - "Sodium carbonate for industrial use - Preparation and storage of test samples" specifies a concise procedure for preparing and storing test samples of sodium carbonate intended for laboratory analysis. Originally published in 1976, the standard sets basic requirements to ensure representative, stable, and properly identified test specimens used in chemical analysis and quality control of industrial sodium carbonate (soda ash).
Key topics and requirements
- Scope: Defines the procedure for preparation and storage of test samples of industrial sodium carbonate for subsequent testing and analysis.
- Sampling workflow:
- Laboratory samples are to be prepared using the appropriate ISO sampling method referenced in the standard.
- A test sample should consist of approximately 500 g of the laboratory sample.
- Container and storage:
- Test samples must be placed in a perfectly dry, airtight container of a capacity such that the container is nearly filled by the test sample, minimizing headspace and exposure to moisture or CO2.
- Marking and traceability:
- Containers must be labelled with the origin and complete identification of the test sample and the date of bottling.
- Purpose: Ensures consistency and repeatability of subsequent chemical analyses (e.g., alkalinity, chloride, sulfate, iron, insoluble matter), by standardizing how samples are prepared, stored and identified.
Applications
ISO 739:1976 is practical for anyone involved in the quality control and laboratory testing of industrial sodium carbonate. Typical users include:
- Quality assurance and QC chemists in soda ash manufacturing plants
- Analytical and testing laboratories performing chemical assays on sodium carbonate
- Procurement and inspection teams validating material conformity
- Regulatory bodies and auditors assessing sampling and storage practice compliance
Using ISO 739 helps prevent sample contamination, moisture uptake, and CO2 absorption that can alter analytical results, thereby improving the accuracy of tests used for specification conformance, process control, and commercial transactions.
Related standards
ISO 739 is part of a suite of ISO methods relating to sodium carbonate testing. Relevant documents include:
- ISO 740 - Determination of total soluble alkalinity (titrimetric)
- ISO 741 - Determination of sodium hydrogen carbonate content (titrimetric)
- ISO 742 - Determination of chloride content (mercurimetric)
- ISO 743 - Determination of sulphate content (gravimetric and photometric)
- ISO 744 - Determination of iron content
- ISO 745 - Determination of loss of mass and of non-volatile matter at 250 °C
- ISO 746 - Determination of matter insoluble in water at 50 °C
Keywords: ISO 739:1976, sodium carbonate test samples, sample preparation, storage of test samples, industrial sodium carbonate, QC sampling, laboratory sample conditioning.
