Quantitation of Four Regulated Phthalates in Plastic Consumer Products by Gas Chromatography– Time-of-Flight Mass Spectrometry

Importance of the Topic

Phthalates are widely used plasticizers in consumer products but raise health concerns due to potential endocrine disruption. Regulatory bodies such as the European Union have banned specific phthalates in sensitive applications like children’s toys and food-contact materials. Accurate quantitation of these compounds in plastics is therefore essential for compliance testing and risk assessment.

Study Objectives and Overview

This application note demonstrates the quantitation of four regulated phthalates—diisobutyl phthalate, dibutyl phthalate, benzyl butyl phthalate, and bis(2-ethylhexyl) phthalate—in a range of plastic consumer products. The study covers surface extraction of two children’s toys, an ink pen barrel, and cross-linked high-density polyethylene (CL-HDPE) plumbing pipe, using a Pegasus BT GC–TOFMS system to achieve sensitive and reproducible measurements.

Methodology

The analytical workflow employed a non-destructive surface extraction: 1–2 g of each sample was sonicated in 10 mL chloroform for 20 minutes. After centrifugation, extracts were transferred to autosampler vials. Calibration standards were prepared in chloroform over a range of 20–10 000 pg/µL. Each extract and standard was injected (1 µL, split 10:1) into the GC–TOFMS system, and external calibration curves were generated in ChromaTOF software for quantitation.

Used Instrumentation

• Gas Chromatograph: Agilent 7890 with L-PAL3 autosampler
• Column: Rxi-5ms, 30 m × 0.25 mm × 0.25 µm (Restek)
• Carrier Gas: Helium, 1.4 mL/min constant flow
• Oven Program: 50 °C (1 min) to 330 °C at 30 °C/min, hold 20 min
• Mass Spectrometer: LECO Pegasus BT GC–TOFMS
• Ion Source Temperature: 250 °C; Transfer Line: 300 °C
• Mass Range: 40–700 m/z; Acquisition Rate: 10 spectra/s

Results and Discussion

Quantitative data expressed in ng/g revealed that all four phthalates were detected across tested samples. CL-HDPE pipe contained 491 ng/g diisobutyl phthalate and 1 011 ng/g bis(2-ethylhexyl) phthalate, while ink pen barrels and toys exhibited higher levels, particularly of bis(2-ethylhexyl) phthalate (up to 114 450 ng/g). Calibration curves for each compound displayed excellent linearity (R² ≥ 0.99995). Total ion and extracted ion chromatograms confirmed clear separation of target analytes. The full-scan TOF data also allowed post-acquisition screening of non-target additives, with automated deconvolution (NTD®) identifying additional polymer additives and co-eluting compounds with high library match scores.

Benefits and Practical Applications

• High Sensitivity: Low detection limits ensure compliance with regulatory thresholds.
• Comprehensive Screening: Full mass range acquisition allows simultaneous targeted quantitation and untargeted profiling.
• Efficient Workflow: Simple surface extraction avoids extensive sample preparation.
• Regulatory Compliance: Reliable quantitation supports product safety certification and quality control.

Future Trends and Potential Applications

The integration of time-of-flight mass spectrometry with advanced deconvolution algorithms will expand applications in non-targeted screening for emerging contaminants. Future work may focus on miniaturized extraction techniques, automated data processing pipelines, and broader libraries for polymer additive identification. Adaptation to high-throughput formats and coupling with complementary techniques (e.g., LC–HRMS) will further enhance analytical coverage.

Conclusion

The LECO Pegasus BT GC–TOFMS platform effectively quantified four banned phthalates in consumer plastics, demonstrating strong linearity, sensitivity, and reproducibility. Its ability to detect additional unknown additives in a single run highlights its utility for both routine compliance testing and comprehensive formulation analysis.