Column Screening for the UPLC Separation of Plastic Additives as Part of Extractables and Leachables Workflows

Significance of the Topic

Effective selection of chromatographic columns is pivotal in extractables and leachables workflows, particularly when analyzing polymer additives in pharmaceutical packaging and medical devices. Robust column screening ensures reliable detection of compounds spanning a broad polarity and molecular weight range, thereby safeguarding product quality and patient safety.

Objectives and Study Overview

This application note demonstrates a systematic approach to evaluate five diverse UPLC columns for separation of eighteen common plastic additives. The primary goal was to identify column chemistries that maximize resolution and efficiency in a rapid screening format, using UV detection as the analytical endpoint.

Methodology and Instrumentation

A standard mixture of eighteen additives, including antioxidants, UV stabilizers, plasticizers, and flame retardants, was prepared in methanol at concentrations optimized for UV absorbance. Chromatographic experiments were performed on an ACQUITY UPLC H-Class system equipped with a photodiode array detector and controlled via MassLynx software. Separation used a binary gradient of water and acetonitrile with 0.1% formic acid, at 0.5 mL/min over a 14.45 min cycle.

Použitá instrumentace

• ACQUITY UPLC H-Class system with PDA detector
• ACQUITY UPLC BEH C18, CSH C18, HSS PFP columns
• CORTECS UPLC C8 and Phenyl columns
• MassLynx software for data acquisition and analysis

Main Results and Discussion

Screening across the five columns revealed distinct selectivity patterns. The CSH C18 column delivered baseline separation of all eighteen analytes in under 11 minutes, outperforming the standard BEH C18, which co-eluted certain species. Superficially porous CORTECS phases offered higher efficiency but varied retention behaviors: the C8 phase separated late-eluting hydrophobes more rapidly, while the Phenyl phase excelled with aromatic additives. The HSS PFP column introduced unique secondary interactions but required further mobile phase optimization to match the CSH C18 resolution.

Benefits and Practical Applications

Column screening of varied stationary phases accelerates method development, reducing time-to-result for extractables and leachables studies. The identification of an optimal column chemistry enables robust workflows in pharmaceutical quality control, packaging compatibility studies, and regulatory compliance testing.

Future Trends and Possibilities

Advances in stationary phase design, including mixed-mode and sub-2 µm particles, will expand selectivity options. Integration of high-resolution mass spectrometry with tailored column screening promises comprehensive profiling of unknown leachables. Additionally, machine learning algorithms may predict optimal column choices based on molecular descriptors, further streamlining method development.

Conclusion

A targeted column screening approach using five UPLC phases demonstrated that charged surface hybrid C18 provided the most comprehensive separation of a complex plastic additive mixture. Adopting such systematic strategies enhances chromatographic method robustness and efficiency in extractables and leachables research.

References

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