ISO 14388-2:2014 PDF

Scope: This part of ISO 14388 specifies a suite of methods used to determine the net acidity in acid sulfate soils. This part of ISO 14388 specifies a method for measuring chromium reducible sulfur (SCR) by iodimetric titration of distilled hydrogen sulfide trapped as zinc sulfide, following acidic chromous chloride digestion. This method determines inorganic sulfides (e.g. pyrite, marcasite, greigite, mackinawite) and elemental sulfur in acid sulfate soil without interferences from organic sulfur and oxidized forms of sulfur such as sulfate. On a separate test portion of soil, the pH in a 1 mol/l KCl soil suspension (pHKCl) is determined. When pHKCl is < 6,5, titratable actual acidity (TAA) is then determined. Subsequently, potassium chloride extractable sulfur (SKCl), calcium (CaKCl), and magnesium (MgKCl) can also be determined. Where jarosite is identified in the soil (or where pHKCl is < 4,5), net acid-soluble sulfur (SNAS) is determined by the difference between hydrochloric acid extractable sulfur (SHCl) and potassium chloride extractable sulfur. On samples where pHKCl is < 6,5, acid neutralizing capacity is determined by measuring either inorganic carbon (CIN) by combustion furnace, or ANCBT (ANC measured by back-titration of acid remaining following an acid digest).

ISO 14388-2:2014 Referenced Document

ISO 1042:1998 Laboratory glassware - One-mark volumetric flasks
ISO 10694:1995 Soil quality - Determination of organic and total carbon after dry combustion (elementary analysis)
ISO 14254:2001 Soil quality - Determination of exchangeable acidity in barium chloride extracts
ISO 14388-3:2014 Soil quality - Acid-base accounting procedure for acid sulfate soils - Part 3: Suspension peroxide oxidation combined acidity and sulfur (SPOCAS) methodology
ISO 1770:1981 Solid-stem general purpose thermometers
ISO 3696:1987 Water for analytical laboratory use; Specification and test methods
ISO 385-1:1984 Laboratory glassware; Burettes; Part 1 : General requirements
ISO 385-2:1984 Laboratory glassware; Burettes; Part 2 : Burettes for which no waiting time is specified
ISO 648:2008 Laboratory glassware - Single-volume pipettes
ISO 835-1:1981 Laboratory glassware; Graduated pipettes; Part 1 : General requirements
ISO 835-2:1981 Laboratory glassware; Graduated pipettes; Part 2 : Pipettes for which no waiting time is specified
ISO 835-3:1981 Laboratory glassware; Graduated pipettes; Part 3 : Pipettes for which a waiting time of 15 s is specified
ISO 8655-1:2002 Piston-operated volumetric apparatus - Part 1: Terminology, general requirements and user recommendations
ISO 8655-2:2002 Piston-operated volumetric apparatus - Part 2: Piston pipettes
ISO 8655-3:2002 Piston-operated volumetric apparatus - Part 3: Piston burettes

2014 ISO 14388-2:2014 Soil quality - Acid-base accounting procedure for acid sulfate soils - Part 2: Chromium reducible sulfur (CRS) methodology