GB/T 39560.1-2020Determination of certain substances in electrical and electronic products - Part 1: Introduction and overview (English PDF)

3.1.7 Reference material

Material, sufficiently homogeneous and stable with reference to specified properties, which has been established to be fit for its intended use in measurement or in examination of nominal properties.

3.1.8 Repeatability

Precision under repeatability conditions.

[GB/T 6379.1-2004, definition 3.13] [1]

3.1.9 Reproducibility

Precision under reproducibility conditions.

[GB/T 6379.1-2004, definition 3.17] [1]

3.1.10 Screening

Analytical procedure to determine the presence or absence of substances in the representative part or section of a product, relative to the value or values chosen as the criterion for presence, absence or further testing.

NOTE: If the screening method produces values that are not conclusive, then additional analysis or other follow-up actions may be necessary to make a final presence/absence decision.

3.2 Abbreviations

The following abbreviations are applicable to this Document.

AAS: Atomic Absorption Spectrometry;

C-IC: Combustion - Ion Chromatography;

CV-AAS: Cold Vapour Atomic Absorption Spectrometry;

CV-AFS: Cold Vapour Atomic Fluorescence Spectroscopy;

EPA: Environmental Protection Agency;

FRU: Field Replaceable Unit;

GC-MS: Gas Chromatography - Mass Spectrometry;

GLP: Good Laboratory Practice;

HPLC-UV: High-Performance Liquid Chromatography - Ultraviolet;

IC: Ion Chromatography;

IAMS: Ion Attached Mass Spectrometry;

ICP-MS: Inductively Coupled Plasma Mass Spectrometry;

ICP-OES: Inductively Coupled Plasma Optical Emission Spectrometry;

IS: Internal Standard;

IUPAC: International Union of Pure and Applied Chemistry;

LOD: Limit of Detection;

LOQ: Limit of Quantification;

MDL: Method Detection Limit;

PBB: Polybrominated Biphenyl;

PBDE: Polybrominated Diphenyl Ether;

PBMS: Performance-Based Measurement System;

PWB: Printed Wiring Board;

QC: Quality Control;

UV-VIS: Ultraviolet-Visible Spectroscopy;

XRF: X-Ray Fluorescence Spectroscopy.

4.1 Field of application

The contents of the test methods to determine the levels of certain substances are grouped into important steps:

a) analytical test methods;

b) laboratory implementation.

Analytical test methods were developed and validated to ensure their suitability to the task. The structure of each of the test methods are generally aligned in accordance with ISO 78-2:1999 where applicable, i.e.:

hexavalent chromium, etc.) in electrical and electronic equipment is widely used in reference to analytical testing methods. Screening methods provide the analyst a convenient approach to evaluate for the presence or quantity of certain substance(s) in samples. Screening may employ qualitative or semi-quantitative methods. In some cases, a quantitative method may be used for screening purposes if the actual targeted substance(s) are difficult to analyze directly (e.g., hexavalent Cr).

Depending on the screening results however, additional analysis methods may need to be employed to definitively verify the presence or quantity of certain substances. These definitive analysis methods are referred to as verification methods.

While X-ray fluorescence spectrometry (XRF) is the tool most commonly associated with the screening approach, it is not limited to this analytical measurement technique. Users of this family of standards will understand that multiple measurement techniques can be employed for the purpose of “screening”.

Screening for hexavalent chromium [Cr(VI)] for example, can be accomplished by a total chromium measurement using a non-destructive XRF analysis method. Similarly, total chromium analysis could be performed by a destructive analysis using an inductively coupled plasma measurement method. Either measurement can be effectively employed to evaluate for the presence or quantity of hexavalent chromium since the concentration of the hexavalent species can be no greater than the total chromium concentration value.

Likewise, a total bromine measurement using a non-destructive XRF analysis method or C-IC method can be used in the same fashion. Either measurement can be effectively employed to evaluate for the presence or quantity (PBBs) or (PBDEs) in a sample when relating the total bromine content to the composition of these compounds.

In both examples however, the detection of elevated total element levels requires additional verification method analysis (e.g., UV-VIS or GC-MS techniques) to confirm the potential presence or quantity of hexavalent chromium [Cr (IV)] or PBB/PBDE compound species.

It can therefore be seen that the prudent analyst can effectively employ different screening procedures to achieve the same result.

The screening procedure may be carried out either by directly measuring the sample (nondestructive sample preparation) or by destroying the sample to make it uniform (mechanical sample preparation). This decision shall be made by judging the uniformity of the sample. A screening of representative samples of many uniform materials (such as polymers, alloys, glass) may be carried out non-destructively, while for other more complex samples (such as an FRU), mechanical sample preparation may be an appropriate solution. Mechanical sample preparation is the same for both the screening and the verification test procedure.

Verification test procedures are often employed to confirm the presence or quantity of certain substances of concern after a screening procedure has been performed (e.g., to determine if the determination of limits of detection (LOD) and limits of quantification (LOQ). Where applicable, the LOD and LOQ section shall be consistent with the descriptions in 4.7. Examples of other method-specific quality control concerns include requirements regarding method blanks, calibration check standards, spike or surrogate samples, internal standard responses and the like.

4.5 Blank solution

Where applicable, the precision clause of the individual test method standards shall include repeatability and reproducibility statements (see Annex B of ISO 78-2:1999) supported by statistical data derived from interlaboratory study or the equivalent.

4.6 Adjustment to the matrix

Test methods for certain substances that are present at relatively low levels amongst other chemical elements or compounds at relatively high concentrations, or those that represent the major constituent of the sample, are very often material or matrix dependent. Therefore, the test methods shall be adjusted to the materials to be tested, either by introducing the appropriate blanks and matrix-adjusted calibration samples, or by a preparation step that separates the analyte from the adherent materials or the main matrix. The main material types (or matrices)

in electronic equipment are polymers (mostly technical polymers containing additives and sometimes having coated surfaces), metals or alloys (they may also be coated) and electronics.

Matrix adjustment may be difficult for electronic products.

4.7 Limits of detection (LOD) and limits of quantification (LOQ)

In its simplest form, a limit of detection (LOD) or method detection limit (MDL) is typically described as the lowest amount or concentration of analyte in a test sample that can be reliably differentiated from zero for a given measurement system.

Instrument detection limits represent an instrument’s ability to differentiate low concentrations of analytes from “zero” in a blank or standard solution, and are commonly used by manufacturers to demonstrate the measurement capability of a system (e.g., atomic absorption spectrometer). Whilst instrument detection limits are useful, they are often considerably lower than a limit of detection representing a complete analytical measurement process.

Complete analytical method detection limits (MDL) are most appropriately determined experimentally by performing replicate, independent measurements on low-level or fortified sample matrices (e.g., plastic) carried out through the entire test procedure, including sample digestion or extraction. A minimum of six replicates and analyte concentrations of 3 ~ 5 times the estimated method detection limit have been suggested as suitable for this analysis. The complete method detection limit for an entire test procedure is determined by multiplying the standard deviation of the replicates by an appropriate factor. IUPAC recommends a factor of 3 for a minimum of six replicates, whilst EPA utilizes a one-sided confidence interval with the multiplier equal to Student’s t value chosen for the number of replicates and the level of confidence (e.g., t = 3.36 for six replicates for 99 % confidence).

NOTE: An illustrative calculation example is given in Annex A.

The limit of quantification (LOQ) or estimated quantitation limit for a given measurement system is typically described as the lowest concentration that can be reliably determined within specified or acceptable limits of precision during routine laboratory operating conditions. The acceptable precision limit is often defined as 10% relative standard deviation or simply expressed as a fixed multiple (2 ~ 10) of the method detection limit.

4.8 Test report

The work carried out by the testing laboratory shall be covered by a report that accurately, clearly and unambiguously presents the test results and other relevant information. Each test report shall include at least the following information:

a) name, address and location of any laboratory involved in the analysis and name of the operator;

b) date of receipt of sample and date(s) of performance of test(s);

c) unique identification of report (such as a serial number) and of each page and total number of pages of the report;

d) description and identification of the sample, including a description of any product disassembly performed to acquire the test sample;

e) a reference to this standard, the method used or performance-based equivalent (including digestion method(s) and equipment);

f) the limit of detection (LOD) or limit of quantification (LOQ);

g) the results of the test expressed as milligram/kilogram (mg/kg) in samples tested;

h) any details not specified in this standard which are optional, and any other factors that may have affected the results. Any deviation, by agreement or otherwise, from the test procedure specified here.

The results of all quality control test (e.g., results from method blanks, matrix spikes, etc.) and a list of reference materials used and their origin shall be available upon request.

Corrections or additions to a test report after issue shall be made only in a further document suitably marked, e.g., “Amendment/Addendum to test report serial number XXX” (or as otherwise identified), and shall meet the relevant requirements of 4.2 ~ 4.6).

4.9 Alternative test methods

Alternative test methods, digestion methods or analytical techniques may be utilized once the performance effectiveness has been validated according to PBMS criteria, referenced in the quality control clauses of the test methods. Any deviation from the described test methods shall