Electronic base material tested for halogen-free definition applying Metrohm Combustion IC

Significance of the Topic

The restriction of hazardous substances, notably halogens, in electronic materials is a critical requirement under RoHS and related IEC standards. Accurate determination of chlorine and bromine in polymeric base materials for printed circuit boards (PCBs) ensures compliance, promotes environmental safety, and upholds product quality in electronics manufacturing.

Objectives and Study Overview

This application note evaluates the performance of Metrohm Combustion IC for quantifying halogen content in PCB base materials according to IEC 61189-2, fulfilling the limits set by RoHS and IEC 61249-2-21. The study aims to demonstrate analytical precision, robustness, and workflow efficiency.

Methodology

Samples of PCB base material were combusted at 1050 °C in an oxygen/argon mixture. The resulting combustion gases passed through an absorption solution and were analyzed using ion chromatography with conductivity detection. Intelligent Partial Loop Injection Technique (MiPT) with Inline Matrix Elimination optimized sample introduction and reduced interferences. Key parameters included a carbonate/bicarbonate eluent, 100 µL injection volume, 0.7 mL/min flow rate, and a 20 min runtime.

Instrumentation Used

• 930 Compact IC Flex with intelligent Partial Loop Injection (2.930.2560)
• IC Conductivity Detector (2.850.9010)
• MSM Rotor A (6.2832.000)
• Combustion Module (oven and ABD) (2.136.0700)
• Autosampler MMS 5000 (6.7304.030) with solid sampling kit (6.7302.000)
• Metrosep A Supp 5 – 150/4.0 (6.1006.520) and guard column Metrosep A Supp 4/5 Guard/4.0 (6.1006.500)
• Metrosep A PCC 1 HC/4.0 column (6.1006.310)

Main Results and Discussion

Analysis of three replicates yielded a mean chlorine concentration of 746.6 mg/kg (RSD 2.8 %) and bromine at 88.4 mg/kg (RSD 2.6 %). Sulfur remained below the quantification limit. The low relative standard deviations demonstrate high repeatability and suitability for routine halogen screening. The method’s sensitivity meets regulatory thresholds for halogen-free definitions.

Benefits and Practical Applications

• Reliable quantification of chlorine and bromine in PCB materials
• Compliance testing for RoHS and IEC standards
• Automated workflow with minimal sample preparation
• High throughput and robust precision for quality assurance

Future Trends and Potential Applications

Advances may include extending the technique to additional halogens and other heteroatoms, coupling with mass spectrometry for speciation, further miniaturization for field analysis, and enhanced automation for large-scale screening in electronics manufacturing.

Conclusion

Metrohm Combustion IC offers a streamlined, precise, and robust solution for the determination of chlorine and bromine in electronic base materials. The method aligns with regulatory requirements and supports quality control in PCB production.

References

• Directive 2011/65/EU on the Restriction of Hazardous Substances (RoHS)
• IEC 61249-2-21: Materials for Printed Boards
• IEC 61189-2: Test Methods for Electronic Components