AS 4439.2:2019 pdf free.Wastes, sediments and contaminated soils Part 2: Preparation of leachates – Zero headspace procedure.
WARNING — SAFETY PRECAUTIONS AS DEFINED IN AS 2243.1, AS 2243.2 AND AS 2243.3 SHOULD BE TAKEN.
Sufficient sample solids shall be present to provide enough leachate to support each of the necessary analyses, taking into account the limits of detection of the various analytical methods used. Additionally, enough sample shall be collected to support any repeat analyses which may be required.
Leaching shall be carried out as soon as possible after receipt of the samples. The leaching shall be completed within 7 days.
NOTE Samples should be refrigerated until testing is completed unless refrigeration results in irreversible physical change.
Where precipitation occurs, the entire sample, including the precipitate, shall be extracted. Preservatives shall not be added to samples before leaching.
Samples shall be collected and stored in a manner to prevent loss of volatile components, i.e. in polytetrafluoroethylene (PTFE) lined screw-capped glass containers, filled to capacity, and opened only immediately prior to preparation for leaching. A sample stored in this PTFE container shall not be used for the determination of PFAS analytes.
7.2 Reduction of sample particle size
Due to the size of the leaching vessel, the possibility of damage to its inner wall, and in order to minimize sampling error, the particle size of the test sample (consisting of at least 250 g), should be reduced to 2 mm to 3 mm. This may be confirmed visually by comparison with a ruled scale, or by screening the material.
Fragments larger than 4 mm may be removed before particle size reduction if they —
(a) comprise less than 10 % by mass of the sample;
(b) are appreciably different in character from the bulk of the sample (e.g. stones, fragments of twigs); and
(c) are not expected to contribute significantly to the leaching of analytes.
If the sample consists mainly of large particles, or if the larger particles are not significantly different to the bulk of the material, then the whole test portion should be reduced to a maximum particle size of 2 mm to 3 mm in such a way as to minimize any loss of analytes of interest.
The sample, mortar and pestle (see Clause 6.9) shall be chilled to less than 4 °C prior to the particle size reduction. Care shall be taken during the particle size reduction to prevent the generation of heat. The particle size reduction should be performed as quickly as possible to reduce the loss of analytes.AS 4439.2 pdf download.