This Standard specifies a method for the determination of peroxide pH (pH_OX), titratable peroxide acidity (TPA) and excess acid neutralizing capacity (ANC_E) in acid sulfate soil following digestion with 30% hydrogen peroxide.

NOTES:

1 The TPA measurement does not quantitatively recover retained acidity held in iron and aluminium hydroxy-sulfate minerals such as jarosite [KFe₃(SO₄)₂(OH)₆] and similar minerals. Methods to determine the retained acidity are given in AS 4969.6 and AS 4969.11.

2 The suspension obtained from this method can be analysed subsequently to determine peroxide sulfur, calcium and magnesium (AS 4969.5) followed by the determination of S_RAS on the digested soil residue (AS 4969.6).