Determination of halogens in polymers and electronics using a combustion ion chromatography system

Importance of the Topic

Electronic devices and polymer-based products increasingly contribute to global waste streams. Alongside regulated metals like lead and mercury, halogens such as fluorine, chlorine, bromine, and iodine in polymer components present environmental and health concerns. International standards (eg. IEC 62321-3-2) and regional directives (eg. RoHS) demand reliable screening methods for halogens in polymers and electronics to ensure regulatory compliance and to inform waste management strategies.

Objectives and Study Overview

The study aimed to develop a robust, fully automated analytical workflow for quantifying key halogens in polymers and electronic materials. Using a combustion ion chromatography (CIC) approach, the authors sought to demonstrate accuracy, precision, and throughput advantages over traditional wet-chemistry digestions, while meeting screening requirements of IEC 62321-3-2.

Methodology

Polymer and printed circuit board (PCB) samples were cryogenically ground to fine powders to ensure homogeneity. Known masses (15–50 mg for polymers, 1–10 mg for PCB) were combusted in a controlled oxygen/argon environment. Combustion products (HX, SO₂) were absorbed in aqueous peroxide solution and delivered directly to ion chromatography. Electrolytically regenerated potassium hydroxide served as eluent with suppressed conductivity detection. Calibration ranges spanned 0.005–8 mg/L for chloride and 0.1–8 mg/L for fluoride, bromide, and iodide.

Used Instrumentation

• Mitsubishi AQF-2100H Automated Combustion System (with Horizontal Furnace, Gas Absorption Unit, Automatic Boat Controller)
• Thermo Scientific Dionex Integrion HPIC System (EGC 500 KOH eluent generator, CR-ATC trap column, AERS 500 suppressor, IonPac AS17-C guard and analytical columns)
• SPEX SamplePrep Freezer/Mill Cryogenic Grinder

Main Results and Discussion

Chromatographic separation of all four halide anions was achieved within 20 minutes. Calibration curves exhibited excellent linearity (r² ≥ 0.9996), except fluoride which followed a quadratic fit. Method precision (RSD < 0.5%) and retention time stability (< 0.2% RSD) demonstrated system robustness. Analysis of four polymer samples revealed variable halogen contents (fluorine: 0–513 mg/kg; chlorine: 4–95 mg/kg; bromine: 0–111 mg/kg; iodine: 0–1307 mg/kg). A PCB sample contained 1314 mg/kg F, 323 mg/kg Cl, and 25 742 mg/kg Br. Recovery experiments using certified reference polyethylene (ERM®-EC680k) yielded RSD of 1.03% and recoveries of 89.9–114%, confirming accuracy.

Practical Benefits and Applications

The CIC approach offers a streamlined, reagent-free workflow that eliminates acid digestions, reduces hazardous waste, and improves laboratory throughput. Fully automated sample combustion and direct injection into IC deliver reproducible, high-throughput screening of halogens. Manufacturers and contract laboratories can apply this method for RoHS compliance, quality control of polymers, and environmental monitoring of electronic waste.

Future Trends and Possibilities

Advancements may include miniaturized combustion modules, integration with mass spectrometry for simultaneous elemental profiling, and expanded applicability to other persistent halogenated compounds. Coupling CIC with hyphenated techniques could further enhance selectivity for emerging environmental contaminants in complex matrices.

Conclusion

The developed CIC method utilizing Mitsubishi AQF-2100H and Dionex Integrion HPIC systems provides a reliable, accurate, and automated solution for quantifying fluorine, chlorine, bromine, and iodine in polymers and electronics. High precision, good recoveries, and compliance with international standards make it well suited for regulatory screening and industrial quality control.

References

1. IEC 62321-3-2: Screening of halogen in polymers and electronics by Combustion-Ion Chromatography.
2. Mello PA, Barin JS, Duarte FA, et al. Analytical Methods for the Determination of Halogens in Bioanalytical Sciences: A Review. Anal Bioanal Chem. 2013;405:7615–7642.
3. Thermo Fisher Scientific. Technical Note 175. Configuring the Integrion RFIC Model of the Dionex Integrion HPIC System. Sunnyvale, CA; 2016.
4. Thermo Fisher Scientific. Technical Note 72211. Combustion Ion Chromatography with a Dionex Integrion HPIC System. Sunnyvale, CA; 2017.
5. Mitsubishi Chemical Analytech. Operation Manual for NSX-2100 Series Automatic Combustion Unit Model AQF-2100H, Section “Instruction Manual of Absorption Unit GA-210.”
6. Thermo Fisher Scientific. Application Note 72349. Determination of Chlorine, Bromine, and Sulfur in Polyethylene Materials Using Combustion Ion Chromatography. Sunnyvale, CA; 2017.