ASTM D5381-93(2021)

• Abstract:

  SIGNIFICANCE AND USE; 5.1 The identification of pigments in a sample of liquid paint or paint film is often important for regulatory purposes. Many inorganic pigments or extenders utilized in past paint formulation are now regulated by federal, state, or municipal health authorities. XRF is one of the more common and convenient methods employed to characterize the pigment composition of a paint formulation. ; 5.2 XRF techniques, in general, do not provide the ability to identify the chemical nature of organic pigments. There are instances where XRF techniques, used in tandem with other analytical methods, such as solid state Carbon 13 Nuclear Magnetic Resonance (C-13 NMR), can identify the organic pigments utilized in coatings. However, XRF provides only an elemental sketch of the inorganic pigmentation. The chemical composition of the pigments is inferred by the analyst from the samples, color, elemental information, and common sense. Small impurities are often found in pigments, so the relative XRF intensities also serve to guide the analyst in proposing the probable pigment present.; SCOPE; 1.1 This guide covers the general considerations for proper use of X-ray fluorescence (XRF) spectroscopy. Because many differences exist between XRF instruments, no detailed operating instructions are provided. The analyst should follow the instructions provided by the manufacturer for his instrument. ; 1.2 The analyst is encouraged to consult the chemical literature, various trade journals, pigment supplier publications, etc., as well as the instrument manuals from the manufacturer. ; 1.3 XRF is commonly employed to determine the elements present in inorganic pigments and extenders, often in concert with other analysis techniques. Organic pigments cannot normally be identified solely by XRF. On occasion, organic pigments contain heavier elements that can distinguish between major classes of these pigments or may serve to distinguish one of the two distinct pigments. However, the analyst should be wary of a qualitative pigment identification solely by XRF technique. ; 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific hazard information see Section 3 on Radiation Concerns. ; 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

• Status: Published
• Publication Date: 31-Jan-2021
• ICS: 87.060.10 - Pigments and extenders
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.21 - Chemical Analysis of Paints and Paint Materials

• Refers: ASTM D3925-02(2010) - Standard Practice for Sampling Liquid Paints and Related Pigmented Coatings
• Effective Date: 01-Dec-2010
• Refers: ASTM D3925-02 - Standard Practice for Sampling Liquid Paints and Related Pigmented Coatings
• Effective Date: 10-Aug-2002
• Refers: ASTM D3925-91(1996) - Standard Practice for Sampling Liquid Paints and Related Pigmented Coatings
• Effective Date: 15-Sep-1991

Overview

ASTM D5381-93(2021), Standard Guide for X-Ray Fluorescence (XRF) Spectroscopy of Pigments and Extenders, is an international standard developed by ASTM International. This guide provides general considerations for the proper use of X-ray fluorescence spectroscopy in the analysis of pigments and extenders, particularly in liquid paints and paint films. XRF spectroscopy is a fast, non-destructive quantitative and qualitative analytical technique widely used in the coatings industry to determine the elemental composition of inorganic pigments and extenders. The standard underscores the regulatory significance of identifying pigments, especially as many previously used inorganic components have become regulated by health authorities.

Key Topics

• Scope of XRF Use: Focuses on using XRF spectroscopy to identify and characterize inorganic pigments and extenders in paints and coatings. The guide does not supply detailed instrument operating instructions due to the diversity of available XRF instruments but refers users to manufacturer documentation.

• Analytical Limitations: While XRF is effective for detecting and analyzing elements in inorganic pigments, it generally does not identify organic pigments. Sometimes, if organic pigments include heavier elements, XRF may distinguish between major classes. For full identification, XRF results are often combined with other analytical techniques, such as carbon-13 NMR.

• Sample Considerations: Paint and pigment samples can be analyzed in solid or liquid forms. Liquid samples are typically sealed and analyzed under helium purge, while solid samples such as powders, pellets, or paint chips are also prepared to minimize contamination and optimize results.

• Instrument Calibration & Operation: The standard emphasizes following instrument manufacturer guidelines for setup, operation, and calibration. Regular calibration, often with standard reference materials such as Stainless Steel #316, is recommended to ensure reliable results.

• Data Interpretation: XRF provides an elemental profile, with data typically interpreted using computer software. However, analysts should supplement this with knowledge of paint composition, color data, and established pigment profiles to accurately infer which pigments and extenders are present.

• Safety Practices: The guide raises awareness of radiation safety, requiring proper dosimetry for personnel, X-ray surveys after equipment maintenance, and compliance with all applicable safety regulations and company policies.

Applications

• Regulatory Compliance: XRF analysis is essential for demonstrating compliance with health and environmental regulations concerning toxic elements in paints and coatings. It enables analysts to detect and quantify elements linked to restricted or controlled substances.

• Quality Assurance in Manufacturing: Paint and pigment manufacturers use XRF spectroscopy for routine quality control, ensuring the elemental specifications and consistency of batches.

• Forensic Analysis: XRF is also used in the forensic analysis of paint samples, assisting in investigations and sourcing by identifying the elemental fingerprint of particular pigments or extenders.

• Heritage Science and Conservation: Conservators apply XRF to study the composition of historical coatings and artworks, minimizing damage and preserving the integrity of valuable objects.

Related Standards

• ASTM D3925: Practice for Sampling Liquid Paints and Related Pigmented Coatings.
• ISO 3497: Determination of elemental composition by X-ray spectrometric analysis.
• ISO 12677: Chemical analysis of refractory products by XRF.

Keywords: X-ray fluorescence (XRF), pigment analysis, paint extender identification, ASTM D5381, inorganic pigments, elemental analysis, coatings, regulatory compliance, spectroscopy, quality control.

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For comprehensive XRF instrument operation and analysis, always refer to the equipment manufacturer’s documentation and consult relevant chemical literature or industry publications. Following ASTM D5381 ensures accurate pigment characterization and supports regulatory, safety, and quality requirements in paint analysis.

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D5381 − 93 (Reapproved 2021)
Standard Guide for
X-Ray Fluorescence (XRF) Spectroscopy of Pigments and
Extenders
This standard is issued under the fixed designation D5381; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This guide covers the general considerations for proper
D3925 Practice for Sampling Liquid Paints and Related
use of X-ray fluorescence (XRF) spectroscopy. Because many
Pigmented Coatings
differences exist between XRF instruments, no detailed oper-
ating instructions are provided. The analyst should follow the
3. Radiation Concerns
instructions provided by the manufacturer for his instrument.
3.1 Modern XRF instrumentation has been designed to
1.2 The analyst is encouraged to consult the chemical
minimize exposure of laboratory personnel to X-ray radiation
literature, various trade journals, pigment supplier
during instrument use. However, most laboratories use dosim-
publications, etc., as well as the instrument manuals from the etry to monitor personnel who are normally present around the
manufacturer. XRF instrument while it is in operation. Such dosimetry
devices are normally read on a monthly basis.
1.3 XRF is commonly employed to determine the elements
3.2 After XRF instrument maintenance (especially where
present in inorganic pigments and extenders, often in concert
the X-ray tube, detector, or shielding has been moved or
with other analysis techniques. Organic pigments cannot nor-
replaced), an X-ray survey of all areas around the instrument
mally be identified solely by XRF. On occasion, organic
(while in operation) is recommended. The results of such a
pigments contain heavier elements that can distinguish be-
survey should be documented and stored for future reference.
tween major classes of these pigments or may serve to
3.3 It is recommended that the laboratory check its compli-
distinguish one of the two distinct pigments. However, the
ance with all applicable local, state, and federal requirements.
analyst should be wary of a qualitative pigment identification
Many companies also have policies concerning use of X-ray
solely by XRF technique.
equipment in their laboratories.
1.4 This standard does not purport to address all of the
3.4 It is common laboratory practice to post placards on all
safety concerns, if any, associated with its use. It is the
entrances to the laboratories containing X-ray equipment that
responsibility of the user of this standard to establish appro-
indicate its presence.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
4. Summary of the Guide
For specific hazard information see Section 3 on Radiation
4.1 A general guide for qualitative elemental analysis of
Concerns.
paint and paint components is provided. Knowledge of the
1.5 This international standard was developed in accor-
elements present in a sample can be used to infer the identity
dance with internationally recognized principles on standard-
of pigments and extenders that may be present. The absence of
ization established in the Decision on Principles for the
specific pigments and extenders can be proven by the absence
Development of International Standards, Guides and Recom-
of their constituent elements. The presence or absence of toxic
mendations issued by the World Trade Organization Technical
elements can be demonstrated. Analysis consists of irradiating
Barriers to Trade (TBT) Committee.
the test specimen with monochromatic X-rays and determining
the energy or wavelength of the fluorescent X-ray emitted by
the specimen. Since different elements emit X-rays with
This guide is under the jurisdiction of ASTM Committee D01 on Paint and
Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.21 on Chemical Analysis of Paints and Paint Materials. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 1, 2021. Published February 2021. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1993. Last previous edition approved in 2014 as D5381 – 93 (2014). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D5381-93R21. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5381 − 93 (2021)
different energy and wavelength under these conditions, the 7.1.1 Liquid paint samples may be introduced directly into
element content of the specimen can be determined by exami- the sample containers and the container sealed to prevent
nation of the X-ray spectrum. The spectrum is recorded either spillage. Normally, the XRF specimen chamber is purged with
on chart paper or magnetic media. Identification of the con- helium while running liquid samples.
stituent
...