AS 4439.3:2019 Wastes, sediments and contaminated soils
5.1 General requirement
Unless otherwise specified, all reagents shall be of analytical reagent grade. All containers shall meet the requirements of Clause 6.1.
5.2 Reagent water
Water of laboratory Grade 1 in accordance with ISO 3696 shall be used.
5.3 Leaching fluid
5.3.1 General .
The leaching fluid shall be tested immediately before use to ensure conformity to the specified pH value. Leaching fluids not prepared immediately prior to use shall also be examined for indication of contamination or deterioration. In the presence of microbial growth, colouration, solid or suspended matter, the solution shall be discarded and fresh leaching fluid prepared.
5.3.2 Leaching fluid pH 2.9
Leaching fluid pH 2.9 shall be prepared as follows:
(a) Add 5.7 mL of glacial acetic acid (P2o = 1.01 g/mL) to 900 mL of water.
(b) Dilute to 1 L with water. The pH of this fluid should be 2.8 to 3.0 and adjustment of pH is not permitted. .
5.3.3 Leaching fluid pH 5.0
Leaching fluid of pH 5.0 shall be prepared as follows: .
(a) Add 5.7 mL of glacial acetic acid (p20 = 1.01 g/mL) to approximately 900 mL of water.
(b) Add 64.3 mL of 1 mol/L sodium hydroxide solution, dilute to 1 L with water and mix well.
(c) Where the pH is not 4.9 to 5.1, adjust by dropwise addition of 1 mol/L acetic acid or 1 mol/L sodium hydroxide solution as appropriate.
(d) Store in an airtight container.
5.3.4 Leaching fluid pH 9.2
Leaching fluid of pH 9.2 shall be prepared as follows: .
(a)  Dissolve 38.2 g of sodium tetraborate decahydrate (borax) in approximately 900 mL of water.
(b) Dilute to 1 L with water and mix well. The pH of this fluid shall be 9.1 to 9.3. Where the pH is not between these levels the fluid shall be discarded. The pH shall not be adjusted.
(c) Store in an airtight container.
6.1 General
All devices with which the sample or leaching fluids come into contact shall be made of a material(s) which will not leach or adsorb analytes, such as –
(a) glass;
(b) polytetrafluoroethylene (PTFE); .
(c) High Density Polyethylene (HDPE) for Per- and Polyfluoro Alkyl Substances (PFAS) determinations [or other fluorine free plastics);
(d) stainless steel Type 316; or
(e) polyethylene, polypropylene or polyvinyl chloride when only inorganic analytes will be determined. These components shall be cleaned so that they do not contribute significantly to the level of analyte being determined.