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Introduction to IEC 62321 on Chemical Analysis of Electronics

Chemical analysis is the process of examining samples to understand their composition and properties. It involves various techniques and methods to determine the presence and concentration of specific chemicals in electronic products. This text will introduce chemical analysis under standard IEC 62321, including sample preparation, screening processes, quality assurance, and the significance of comprehensive test reports.

The Gist of IEC 62321

In chemistry testing of electronics, chemists define a sample as a substance made of polymers, metals, or plastic materials. It is a representative specimen that undergoes various tests and evaluations to gather information about its chemical composition. These samples can exist in diverse forms, such as powders, liquids, solids, or complex structures like electronic components.

IEC 62321 is a standard published by the International Electrotechnical Commission titled: Determination of certain substances in electrotechnical products. Its objective is to detail the best common practices for testing electrical and electronic equipment (EEE).

IEC 62321 is made of a dozen of parts, including:

  • Part 1 – Introduction and overview
  • Part 2 – Disassembly, disjointment and mechanical sample preparation
  • Part 6 – Polybrominated biphenyls and polybrominated diphenyl ethers in polymers by gas chromatography- mass spectrometry (GC-MS)
  • Part 8 – Phthalates in polymers by gas chromatography-mass spectrometry (GC-MS), gas chromatography-mass spectrometry using a pyrolyzer/thermal desorption accessory (Py/TD-GC-MS)

This compilation of standards primarily serves RoHS (Restriction of Hazardous Substances) assessments of EEE. To get familiar with the entire RoHS testing process, let us discuss IEC 62321-1 – introduction and overview.

IEC 62321

IEC 62321-1

The sections of this part of IEC 62321 describe the following five testing steps.

Table - Five Steps of Analytical Testing, as Outlined by IEC 62321-1


Key Points

1. Sample Preparation

Mechanical methods like microwave digestion and grinding to ensure homogeneity of samples

2. Screening Process

Evaluating chemical concentrations in samples

3. Techniques for Chemical Screening

Destructive (ICP-MS) and non-destructive (XRF) methods

4. Quality Assurance in Chemical Analysis

Ensuring accuracy and reliability of test methods

5. Comprehensive Test Reports

Documenting analysis details and responsible personnel

Let us detail the critical aspects of these sections.

Step 1. Sample Preparation: Ensuring Homogeneity

Before analysis, it is essential for the requester and the laboratory to agree if they need to prepare a homogenous sample. Homogeneity ensures that the sample is consistent throughout, enabling accurate and reliable results. In some cases, depending on the specific requirements of the analysis or chemical testing, the sample may require additional preparation steps to ensure its suitability. Mechanical sample preparation techniques, including microwave digestion and grinding, can be employed to break down the sample and enhance its homogeneity.

EU RoHS product categories

Step 2. Screening Process: Evaluating Chemical Concentrations

Once the technician adequately prepares the sample, the screening process can commence. Screening involves the evaluation of the chemical concentration within the sample, for example, substances outlined in RoHS. The primary objective of this screening is to determine if the concentrations of these substances meet the specified regulatory limits.

The screening process often employs X-Ray Fluorescence Spectroscopy (XRF) as the preferred technique due to its versatility and wide range of applications, such as testing the amount of heavy metals present in the sample. However, it is worth noting that alternative approaches exist and may be utilized depending on the specific requirements of the analysis. These techniques are either destructive or non-destructive. Destructive methods involve altering or destroying the sample during analysis, while non-destructive techniques allow for preserving the sample’s integrity.

IEC62321-1 Chemical Screening

Step 3. Techniques for Chemical Screening

Considerations for the choice of the analysis technique depend on the nature and value of the sample. For instance, If the sample is of considerable historical or monetary value, such as an old coated piece embedded with precious gold, non-destructive methods such as XRF are suggested to avoid damaging or altering the precious artifact. Conversely, destructive methods like inductive-coupled plasma can be employed when dealing with quality control samples selected randomly from bulk production, as they provide more detailed information about the chemical composition.

To illustrate further, hexavalent chromium, a restricted substance under RoHS, can be primarily screened by measuring the total amount of chromium present in the sample. XRF can achieve this determination in a non-destructive way, while   provides this determination destructively. Since the amount of hexavalent chromium is generally lower than the total chromium content, if the total chromium concentration satisfies the RoHS requirements, further investigations may not be necessary. However, if the total amounts of chromium or bromine exceed the EU RoHS limits (100 ppm for total chromium and 1000 ppm for total bromine), additional steps in the screening process, such as UV-Vis spectroscopy for chromium or gas chromatography for bromine, become crucial to ensure compliance.

While non-destructive methods are typically sufficient for uniform materials, more complex samples demand additional considerations. In these cases, experts recommend creating a proper sample through mechanical sample preparation techniques, such as grinding or dissolving it in an appropriate solvent. This approach aids in achieving a homogeneous and representative sample, allowing for accurate analysis of the complex material. Electronic products, in particular, pose a challenge due to their diverse composition, encompassing polymers, metals, coatings, and various additives. Thus, the analyst must adjust the testing matrix to ensure comprehensive analysis.

XRF spectrum

Step 4. Quality Assurance in Chemical Analysis

Throughout the analysis process, maintaining quality assurance is of utmost importance. This quality assurance involves implementing rigorous quality control measures to validate the accuracy and reliability of the test methods. These quality control tasks include measuring a blank solution before starting the analysis to ensure there is no contamination or interference and monitoring internal-standard responses to assess the consistency of the analytical method. ISO 17025 serves as a universal standard for quality control in laboratories.

Technicians often perform independent measurements in replicates to increase the certainty of the results. By conducting multiple measurements of the same sample under identical conditions, analysts can evaluate the analytical method’s precision and repeatability. It also allows for a better assessment of the uncertainty associated with the results. A common practice is to perform six replicates or more, with the analyte concentration falling within 3 to 5 times the estimated method detection limit to increase the trustability of the results.

Step 5. Comprehensive Test Reports: Documenting Analysis Results

Upon completion of the analysis, the lab generates a comprehensive test report to document the findings. This report is a vital record of the entire analytical process and contains crucial information for traceability and accountability purposes. It typically includes the name and address of the laboratory, as well as the responsible personnel involved in the analysis. Complete details regarding the sample, including its origin, collection method, and any relevant characteristics, are also included. Additionally, the report provides a detailed description of the analysis method utilized, including the techniques, instruments, and parameters employed. By providing this comprehensive information, the test report facilitates transparency and aids stakeholders and regulatory bodies in interpreting and utilizing the analysis results effectively.

IEC 62321 Methodology for Reliable Test Reports

In conclusion, the analysis of samples encompasses the five steps above, ranging from sample preparation to screening and subsequent analysis of specific chemicals. The choice of analysis techniques, whether destructive or non-destructive, depends on the nature of the sample and the analysis requirements. Stringent quality control measures ensure the results’ accuracy, reliability, and traceability. By adhering to these protocols, laboratories can provide comprehensive test reports that contribute to informed decision-making and regulatory compliance.

If you have any further questions or need assistance with chemical analysis, please don’t hesitate to contact Enviropass. We are here to help you with your analytical needs and provide expert guidance. Contact us today to discuss your requirements and how we can support your endeavors.