ISO 3696 Water for analytical laboratory use - Specification and test methods
1 Scope and field of application
This International Standard specifies the requirements and corresponding test methods for three grades of water for laboratory use for the analysis of inorganic chemicals.
It is not applicable to water for organic trace analysis, to water for the analysis of surface active agents, or to water for biological or medical analysis.
NOTE For some purposes (for example for certain analytical methods or for tests in which the water is required to be sterile or pyrogen-free or of specified surface tension), additional specific tests and further purification or other treatment may be necessary.
2 Description
The material shall be a clear, colourless liquid as assessed by visual inspection.
3 Classification
This International Standard covers three grades of water as follows:
Grade 1
Essentially free from dissolved or colloidal ionic and organic contaminants and suitable for the most stringent analytical requirements including those of high-performance liquid chromatography; should be produced by further treatment of grade 2 water (for example reverse osmosis or deionization followed by filtration through a membrane filter of pore size 0.2 μm to remove particulate matter or redistillation from a fused silica apparatus).
Grade 2
Very low in inorganic, organic or colloidal contaminants and suitable for sensitive analytical purposes, including atomic absorption spectrometry (AAS) and the determination of constituents in trace quantities; should be produced, for example, by multiple distillation, or by deionization or reverse osmosis followed by distillation.
Grade 3
Suitable for most laboratory wet chemistry work and preparation of reagents solutions; should be produced, for example, by single distillation, by deionization, or by reverse osmosis. Unless otherwise specified, it should be used for ordinary analytical work.
NOTE It is assumed that the initial feed stock water is potable and reasonably pure. If it is heavily contaminated in any respect, some pretreatment may be necessary.
4 Requirements
The material shall comply with the appropriate requirements of the Table. Testing for compliance shall be carried out by means of the methods specified in clause 7.
