Enhanced RoHS Compliance Testing with Agilent 5800 ICP-OES

Significance of the Topic

Increasing waste of electronic equipment demands strict control of hazardous substances in plastics used in these products to protect health and environment. Compliance with RoHS regulations requires accurate detection and quantitation of restricted elements such as Cd, Cr, Pb, and Hg in polymer materials to ensure product safety and facilitate recycling.

Aims and Study Overview

This study presents a robust method for multi element analysis of plastics employing an Agilent 5800 Vertical Dual View Inductively Coupled Plasma Optical Emission Spectrometer. Certified reference material and two real life plastic samples from consumer electronics and electric vehicles were analyzed to demonstrate compliance with RoHS limits and to evaluate method performance across essential metrics.

Methodology

Samples were prepared by removing metal components and digesting approximately 250 mg in a single stage microwave program using aqua regia followed by dilution to 50 mL. Calibration standards covered working ranges for As, Cd, Cr, Pb, Hg, Sb, Sn, S, and Zn. Continuing calibration verification solutions and an yttrium internal standard at 5 mg/L monitored stability and corrected for matrix effects. Spike recovery experiments assessed accuracy in complex matrices.

Used Instrumentation

• Agilent 5800 VDV ICP-OES with vertical plasma and solid state radio frequency generator
• SeaSpray concentric glass nebulizer, double pass cyclonic spray chamber, Easy Fit semi demountable torch with quartz injector
• Cooled Cone Interface for axial view trace element measurement
• SPS 4 autosampler and ICP Expert software with Intelligent Rinse functionality
• MARS 6 microwave digestion system with iPrep vessels

Main Results and Discussion

• Calibration linearity for all analytes was excellent with correlation coefficients R > 0.9995
• Low detection limits (LOD) and quantitation limits (LOQ) well below RoHS thresholds, for example Cd LOD 0.19 µg/L and Pb LOD 3.30 µg/L
• Method detection limits considering sample prep were sufficient to meet at least one hundredth of RoHS limits
• CRM recoveries ranged from 97 to 106 % confirming accuracy of the digestion and analysis procedure
• Spike recoveries in real life samples fell between 94 and 108 %, with relative standard deviations below 2.3 % indicating high precision
• Long term stability over seven hours showed CCV recoveries within 100 ±10 % and RSDs under 1.4 % for all analytes
• Internal standard recoveries remained within 100 ±7 % across the entire sequence, reflecting robust matrix tolerance
• Intelligent Rinse reduced rinse times by 20 to 30 % while maintaining analytical integrity

Benefits and Practical Applications

• Efficient compliance testing for RoHS and similar regulations in electronics manufacturing and recycling
• Increased throughput through adaptive rinse and automated method setup
• Reduced reagent and argon consumption, lowering operational costs
• Reliable performance for routine quality control of plastic components in various industries

Future Trends and Potential Applications

• Integration of AI driven method optimization and data analysis for enhanced accuracy and speed
• Adoption of high throughput and fully automated sample preparation systems
• Miniaturized and portable ICP-OES instruments for on site screening of materials
• Expansion to new regulatory frameworks and emerging contaminants beyond current RoHS scope
• Coupling with complementary techniques such as mass spectrometry for isotope and speciation studies

Conclusion

The Agilent 5800 VDV ICP-OES coupled with single stage microwave digestion provides a sensitive, accurate, and stable solution for multi element analysis of plastics. This method supports efficient RoHS compliance testing by delivering reliable quantitation of critical heavy metals within regulatory limits, while offering operational advantages in throughput and cost effectiveness.

Reference

1. Baldé C P et al Global E waste Monitor 2024 International Telecommunication Union and United Nations Institute for Training and Research
2. Directive 2011 65 EU on Restriction of Hazardous Substances in Electrical and Electronic Equipment
3. Commission Delegated Directive EU 2023 1437 adapting Annex IV to Directive 2011 65 EU regarding mercury exemption
4. Ramona M G Madalina E G Waste Electrical and Electronic Equipment A Review on the Identification Methods for Polymeric Materials Recycling 2019 4 32
5. Nham T T Monitoring Heavy Metals by ICP OES for Compliance with RoHS and WEEE Directives Agilent Publication IO 040 2010
6. Intelligent Rinse for ICP OES Agilent Publication 5991 8456EN
7. RoHS 3 EU Directive 2015 863 Overview and Requirements