Introduction: The regulatory importance of heavy metals for packaging safety
The chemical safety of packaging materials is one of the most basic requirements of the European Union Packaging Regulation (PPWR) and its predecessor, Directive 94/62/EC on packaging and packaging waste. This legal framework strictly regulates the occurrence of four priority heavy metals in packaging materials to minimize the environmental impact of packaging, to ensure the integrity of recycling processes, and risks to human health from soil, water and air in the waste disposal phase to avoid. Nano-Test Labor Services carries out the heavy metal analyzes required under the PPWR with the latest measuring devices and GLP-compliant validation procedures; We not only provide our customers with reliable analytical data, but also a comprehensive service that includes the interpretation of the results in a regulatory context.
Regulated heavy metals under the PPWR and Directive 94/62/EC
The PPWR and its underlying directive 94/62/EG set clear and binding limits for the heavy metal concentrations that may be found in packaging materials. Accordingly, it is forbidden for the packaging or individual packaging components to have a concentration of lead (Pb), cadmium (CD), mercury (Hg) and hexavalent chromium (Cr(VI)) with 100 ppm (mg/kg) of the exceeds total weight. This threshold applies not only to the final form of Packaging, but applies separately to all packaging components, including inks, paints, coatings, adhesives, dyes and recycled raw materials.
The following table summarizes the regulated heavy metals, their chemical symbols, the total concentration limit in the context of PPWR and the typical reasons for their occurrence in packaging materials:
| Heavy metal | Chemical symbol | PPWR Overall Limit (PPM) | Typical reasons for the occurrence in packaging |
|---|---|---|---|
| Lead | PB | ≤ 100 (Sum of four metals) | PVC stabilizers, pigments, solders, recycled materials |
| Cadmium | Cd | ≤ 100 (Sum of four metals) | Bright yellow/orange/red pigments, PVC stabilizers, coatings |
| Mercury | HG | ≤ 100 (Sum of four metals) | Preservatives used as biocides, fungicides, catalyst residues |
| Hexavalent chrome | Cr(VI) | ≤ 100 (Sum of four metals) | Anti-corrosion coatings, chromate-containing surface treatments, pigments |
Note: The limit is calculated based on the dry weight of the packaging, the packaging component or the packaging waste. The limit of 100 ppm applies to the arithmetic sum of the concentrations of the four metals.
Analytical methodology and instrumentation in the Nano Test Laboratory
In the nano test laboratories, the quantitative determination of heavy metals in packaging samples is carried out in full compliance with internationally recognized standard methods (EN 15586, EPA 3052, ISO 11885, EN ISO 17294-2). Our analytical workflow is secured by the GLP principles in every phase - from sample preparation to data evaluation.
Sample preparation by microwave-assisted acid digestion
The homogenized packaging sample is first weighed on a high-precision scale and then in a closed microwave digestion system under controlled temperature and controlled pressure in a mixture of high-purity nitric acid (HNO₃) and, if necessary, hydrochloric acid (HCl) or Hydrogen peroxide (H₂O₂) completely dissolved. This step ensures that the metals bound in the sample matrix are transferred to the free ionic form and processed for analysis. The solution obtained after decomposition is fed to instrumental analysis using suitable dilution factors.
Quantitative determination by ICP-MS and ICP-OES
Two complementary instrumental platforms for the quantitative determination of heavy metals are used in our laboratory. The following table compares the basic properties, advantages and scope of these two techniques in Nano-Test:
| Feature | ICP-MS (inductively coupled plasma - mass spectrometry) | ICP-OES (inductively coupled plasma – optical emission spectrometer) |
|---|---|---|
| Functional principle | Separation and counting of the plasma ionized elements based on their mass-to-charge ratio (m/z) | Measurement of the radiation emitted by the elements excited in the plasma at their characteristic wavelengths |
| Typical limit of determination (LOQ) | 0.001 – 0.1 ppm (in µg/l range) | 0.01 – 0.5ppm |
| Advantages | Determination in the ultra-track range; high sensitivity at very low concentrations; Possibility of isotopic analysis | Higher matrix compatibility; wide linear measuring range; Fast multi-element analysis |
| Scope of application for nano-test | Determination of lead (Pb), cadmium (CD), mercury (Hg) and other trace metals in the PPB range | Samples with higher concentrations, matrix effect management and complementary validation |
Specific method for determining hexavalent chromium (Cr(VI))
The analysis of hexavalent chromium (Cr(VI)) differs methodically from the determination of the total chromium. Cr(VI) is the most toxicologically risky chromium form and is subject to specific limit values within the framework of the PPWR. Cr(VI) determination in the nano-test laboratory is carried out by a validated method based on alkaline extraction (EPA 3060a), complex formation with diphenylcarbazide (DPC) and a quantitative measurement by UV-VIS spectrophotometry based. If necessary, additional validation is carried out using ion chromatography (IC).
Quality control and method validation
All heavy metal analyzes carried out in the Nano Test laboratory are carried out as part of a quality management system that is fully in line with the GLP principles and the requirements of ISO 17025 accreditation. The following table summarizes the quality control parameters and acceptance criteria used in each analysis series:
| Quality Control Parameters | Frequency of Application | Acceptance criterion |
|---|---|---|
| Blind sample | At least 1 per series | < LOQ (below the determination limit) |
| Certified Reference Material (CRM) | At least 1 piece per series | Recovery within ±10% of the certificate value |
| Recovery at Matrix Spike | For every matrix type in every series | Recovery rate between 80% and 120% |
| Duplicate analysis | 1 Piece per 10 samples | Relative Percentage Difference (RPD) ≤ 20% |
| Independent Quality Control Standard (IQC) | 1 of 10 samples | Within ±10% of the expected value |
The integrated service approach and the reporting of Nano-Test
As a Nano-Test Labor Services, we do not offer heavy metal analyzes as an isolated test, but as an integral part of the PPWR conformity process. The added value we offer our customers goes beyond pure analytical measurement and includes the following steps:
- Supply Chain Analysis: In the case of multi-layer and multiple-component packaging structures, a separate analysis is carried out for each individual layer or component (ink, adhesive, coating, main support material) to precisely determine the source of a possible limit value violation.
- Evaluation of regulatory conformity: The results obtained are compared with the total limit of 100 ppm, whereupon a declaration of conformity or non-conformity is issued for each component and the final packaging.
- Technical Reporting and Consulting: A comprehensive technical report will be prepared, containing all analytical data, quality control results and regulatory assessment. In the event of non-conformity, the customer is given recommendations for corrective actions to correct the cause of the problem.
To ensure the conformity of your European market packaging for heavy metals, fully meet the PPWR requirements and protect your supply chain from regulatory risks, you can contact our team of experts for detailed information on accredited heavy metal analyzes and technical advice. to get from Nano Test.