ISO 12914-2012 PDF

Full title and description

ISO 12914:2012 — Soil quality — Microwave-assisted extraction of the aqua regia soluble fraction for the determination of elements. Specifies a closed‑vessel microwave extraction procedure using aqua regia to produce an extract suitable for instrumental determination of selected trace and major elements in soils and soil‑like materials.

Abstract

This International Standard defines a microwave‑assisted aqua regia extraction method as an operationally defined procedure to release the aqua regia–soluble fraction of elements from soils for subsequent analysis (e.g., AAS, ICP‑OES, ICP‑MS). The method notes limitations (it is not a total digestion for refractory matrices) and gives procedural parameters and quality‑control recommendations. Typical microwave conditions and practical cautions (volatile element handling, contamination risks) are described.

General information

• Status: Withdrawn (revised).
• Publication date: February 2012 (edition 1).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 13.080.10 — Chemical characteristics of soils.
• Edition / version: Edition 1 (2012).
• Number of pages: 7 pages (official ISO English edition).

Scope

ISO 12914:2012 applies to the microwave‑assisted extraction of elements from all types of soil and soil material using aqua regia as the extracting reagent. It is intended to produce the aqua regia‑soluble fraction for subsequent instrumental determination of trace and major elements; it does not claim to produce a total dissolution of refractory compounds (for example SiO2, TiO2, Al2O3). The method is presented as a modular extraction procedure to be used with appropriate quality control and reference materials.

Key topics and requirements

• Definition of the aqua regia‑soluble fraction and caution that this is an operationally defined, not total, digestion.
• Closed‑vessel microwave extraction parameters (example: heating to about 175 °C for ~10 min in a closed vessel — procedural details and tolerances provided in the standard).
• Requirements for reagents, apparatus, and sample pretreatment (homogenization, subsampling) in accordance with related soil sampling standards.
• Quality‑control measures: use of blanks, certified reference materials, replicate digests and checks for contamination and volatile element losses.
• Suitability of extracts for downstream instrumental techniques (FAAS, GFAAS, HGAAS, CVAAS, ICP‑OES, ICP‑MS) and noted analytical interferences (e.g., chloride).

Typical use and users

Used by environmental testing laboratories, soil scientists, research institutions, and regulatory monitoring bodies for routine monitoring and determination of the aqua regia‑soluble metal fraction in soils, sludge and soil‑like materials. Also used by laboratory managers to harmonize extraction procedures and by method developers when comparing extraction performance.

Related standards

ISO 12914:2012 has been revised and its scope incorporated into later work on aqua regia digestions (see ISO 54321:2020, which provides updated procedures for aqua regia digestion of soils, sludge and treated biowaste and specifies both thermal and microwave approaches). Other related references include general sample pretreatment and characterization standards (for example ISO standards on sample preparation and soil quality modules).

Keywords

soil quality; aqua regia; microwave extraction; soil digestion; element determination; ICP‑MS; ICP‑OES; AAS; extraction method; environmental monitoring.

FAQ

Q: What is this standard?

A: ISO 12914:2012 is an ISO method specification describing a closed‑vessel microwave‑assisted aqua regia extraction to obtain the aqua regia‑soluble fraction of elements in soil for instrumental analysis.

Q: What does it cover?

A: It covers the principle, safety remarks, reagents and apparatus, sampling and sample pretreatment, the microwave extraction procedure and performance/quality control for determining the aqua regia‑soluble elemental fraction. It clarifies limitations (not a total digestion for refractory minerals).

Q: Who typically uses it?

A: Environmental and commercial testing laboratories, regulators, researchers and any organization needing a standardized aqua regia extraction protocol for soils and related materials.

Q: Is it current or superseded?

A: ISO 12914:2012 has been withdrawn and was revised by later work; ISO documents indicate it was superseded by ISO 54321 (published 2020) which consolidates and updates aqua regia digestion procedures. The original ISO 12914:2012 listing is shown as withdrawn. National implementations may record specific withdrawal dates.

Q: Is it part of a series?

A: It is part of ISO/TC 190 (Soil quality) chemical‑method modules and is related to other ISO soil analysis and sample‑preparation standards; the method is a module that can be used alongside complementary ISO soil quality standards.

Q: What are the key keywords?

A: aqua regia, microwave extraction, soil quality, element determination, soil digestion, ICP, AAS, extraction method.