Schedule B3 - COAG Standing Council on Environment and Water

5.1.4.4 Partitioning of dry samples to obtain representative analysis portions
The analysis portion of the dry sample must be a representative sample. For sufficiently dry
samples, use of a chute splitter (riffler) is recommended, or the entire sample should be
thoroughly mixed and divided using the ’cone-and-quarter‘ technique or by any other suitable
sampling apparatus. This equipment should be made of appropriate material (i.e. stainless
steel) to avoid contamination.
Repeat partitioning to obtain the desired amount of analysis portion (including any replicate
analyses and extra portions required for quality assurance purposes). Store the remaining
homogenised dry sample separately in a glass screw-cap jar or other appropriate vessel.
Note: Mechanical grinding of dry soil, for example, in a ring mill, will mix the sample, but use
of the cone-and-quarter technique or a mechanical sample divider is preferred, to avoid subsampling
only the larger particles.
5.2 Summary – non-volatiles and semi-volatiles
5.2.1 Preparation of dried samples (e.g. non-volatiles):
1. Remove vegetation and large stones and other particles (> 5 mm) unless they are to be
included for bulk analysis. Record proportion by weight with a description of each fraction
of material removed.
2. Air-dry at least 25% by weight or 200 g of the laboratory sample, whichever is the smaller,
including sufficient amounts for repeat analyses or other analysis on this same sample
including moisture content (using field-moist sample).
3. Samples may also be oven dried at 40 ± 3°C. Sample is dry when the loss in soil mass is not
greater than 5% per 24 hours. (Note caveats in 5.1.4.)
4. Grind to disaggregate the soil particles, using a clean mortar and pestle.
5. Pass through a 2 mm mesh sieve.
6. Weigh and set aside the particles >2 mm diameter for later analysis if required (and to
examine for large particles of solid contaminant if necessary).
7. Partition the fraction