Cosmetic Products Analysis by Pyrolysis-Comprehensive Two-Dimensional Gas Chromatography with Time-of- Flight Mass Spectrometry Detection (Py-GCxGC-TOFMS)

Significance of the Topic

Complex cosmetic formulations require advanced separation techniques to ensure quality control and trace impurity detection in personal care products. Pyrolysis combined with comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry (Py-GCxGC-TOFMS) addresses this need by offering high-resolution analysis with minimal sample preparation.

Objectives and Study Overview

This study evaluated Py-GCxGC-TOFMS for profiling three commercial mascara formulations labeled Sample 1, Sample 2, and Sample 3. The goals included:

• Differentiating minor compositional variations
• Identifying trace contaminants
• Demonstrating the enhanced separation capacity of GCxGC

Methodology

The approach involved thermal degradation of approximately 1 mg of each sample at 750 °C for 15 seconds, followed by comprehensive GC separation and TOFMS detection. Data processing used spectral deconvolution and retention time matching to compare peak lists across samples.

Used Instrumentation

• Pyrolysis Unit: CDS 2000 at 750 °C for 15 seconds
• One-Dimensional GC: Agilent 6890 with Rtx-1MS column (30 m × 0.25 mm × 0.25 μm)
• Comprehensive GCxGC: Agilent 6890 with LECO Thermal Modulator and secondary DB-WAX column (1 m × 0.1 mm × 0.1 μm)
• Mass Spectrometer: LECO Pegasus TOFMS (EI 70 eV, m/z 35–400)

Main Results and Discussion

One-dimensional analysis yielded 114–120 peaks per sample. Automated comparison flagged formulation differences such as presence or absence of specific monomers and additives. GCxGC-TOFMS expanded detection to over 500 peaks, revealing distinct chemical class patterns (alkanes, alkenes, nitriles, acids) in two-dimensional contour plots. Extracted ion chromatograms simplified cross-sample comparison, showing nitrile deficiency in Sample 2 and acid deficiency in Sample 3.

Benefits and Practical Applications

• Minimal sample preparation and low sample consumption
• Enhanced chromatographic resolution for complex mixtures
• Reliable identification of trace components for quality control and deformulation

Future Trends and Applications

Emerging developments may include higher modulation frequencies for sharper peaks, integration with chemometric tools for automated fingerprinting, and extension of the technique to other cosmetic categories and polymer-based materials.

Conclusion

Py-GCxGC-TOFMS demonstrates powerful capabilities for detailed characterization of cosmetic formulations, offering high peak capacity, rapid analysis, and robust contaminant detection. This makes it a valuable tool for analytical chemists in quality assurance, regulatory compliance, and product development.