Analysis of Coffee Packaging and Filter Leachates from Various Single-Serve Coffee Pod Suppliers Using GCxGC-TOFMS

Significance of the Topic

The widespread use of single‐serve coffee pods has raised concerns about the transfer of plastic additives, including phthalates and bisphenol A, into brewed beverages. Understanding and detecting these low‐level contaminants is essential for consumer safety, regulatory compliance, and quality assurance in the food industry.

Objectives and Study Overview

This study aimed to evaluate potential leachates from various commercial coffee pod materials by:

• Extracting brewed coffee with dichloromethane to isolate organic contaminants.
• Applying comprehensive two‐dimensional gas chromatography coupled with time‐of‐flight mass spectrometry (GCxGC‐TOFMS) for enhanced separation and detection.
• Demonstrating the method’s sensitivity by spiking brewed coffee with a phthalate and bisphenol A standard mixture.

Methodology and Instrumentation

Coffee brewed under standardized conditions (~215 mL) was cooled and extracted with 10 mL dichloromethane. Aliquots were directly injected into the GCxGC‐TOFMS system without further cleanup. Key parameters included splitless injection, helium carrier gas, a 60 m primary column (Rxi-1ms) followed by a 1 m secondary column (RTX-200), and a 2 s modulation period. Data acquisition spanned m/z 40–700 at 100 spectra/s. Automated deconvolution and peak detection in ChromaTOF® software enabled reliable identification of trace compounds.

Instrumentation Used

• LECO Pegasus® 4D GCxGC‐TOFMS system
• ChromaTOF® 4.50 data processing software

Key Results and Discussion

Non‐spiked coffee extracts revealed over 1,200 chromatographic features, with large endogenous peaks such as caffeine producing vertical streaks under cryogenic modulation. Spiked samples at 50 ppb per compound showed clear separation of phthalate isomers and bisphenol A, even in cases of near‐coelution on the first dimension. Unique fragment ions (e.g., m/z 163, 149) allowed unambiguous differentiation of analytes from matrix interferences like ethyl vanillin. Sub‐10 ppb levels of diisobutyl phthalate, di-n-butyl phthalate, di-n-pentylphthalate, and benzyl butyl phthalate were confidently detected in unspiked samples.

Benefits and Practical Applications

• High peak capacity and cryofocusing boost detection of low‐level contaminants in complex food matrices.
• Automated deconvolution reduces manual interpretation and enhances throughput.
• Applicable to routine QA/QC of single‐serve pod products, supporting regulatory monitoring and material screening.

Future Trends and Potential Applications

Advances in GCxGC stationary phases and faster acquisition rates will further improve sensitivity and resolution. Integration with high‐resolution accurate‐mass spectrometry could enable non‐targeted screening of emerging contaminants. Expanded libraries and AI‐driven deconvolution promise streamlined workflows for complex food safety applications.

Conclusion

The combination of dichloromethane extraction and GCxGC‐TOFMS provides a robust, sensitive approach for detecting plastic additives in single‐serve coffee. The method’s high separation power and automated deconvolution ensure confident identification of both expected and unexpected leachates, offering a valuable tool for industry and regulatory laboratories.