New Approach to Food Smell Analysis Using Combination of GCMS™ and GC-SCD (2)

Importance of Food Odor Analysis via GCMS and GC-SCD

Food aromas, particularly those of fermented foods like kimchi, depend heavily on sulfur-containing compounds that often occur in trace amounts. Conventional GCMS excels in broad qualitative profiling but may miss low-abundance sulfur analytes due to limited sensitivity and coelution. Employing sulfur chemiluminescence detection alongside GCMS enables targeted, sensitive analysis of sulfur odorants, enhancing accuracy in flavor and quality evaluation of food products.

Objectives and Study Overview

This study investigates a dual-instrument approach combining GCMS for comprehensive qualitative analysis with GC-SCD for selective, high-sensitivity detection of sulfur species. Using residual headspace odors from a washed kimchi container, the method aims to detect and identify sulfur compounds that contribute to food smell and might be overlooked by GCMS alone.

Methodology and Instrumentation

• Sample Preparation: A kimchi container was rinsed, cut, and 1 g of material placed in a 20 mL vial, heated to 80 °C for 30 min. Headspace volatiles were collected onto a DVB/CAR/PDMS SPME fiber.
• GC-SCD Setup: Nexis GC-2030 with SCD-2030 detector, InertCap 5MS/Sil column (30 m×0.32 mm, 0.5 µm), carrier gas He at 44.5 kPa, column program 50 °C (5 min) to 250 °C at 10 °C/min, detector in H₂/N₂/O₂/O₃ gas streams at specified flows.
• GCMS Setup: AOC-6000 autosampler, GCMS-QP2020 NX with same column and carrier conditions, EI ionization at 70 eV, scan mode, SPME desorption at 250 °C, event time 0.3 s.

Main Results and Discussion

The combined technique enabled identification of 36 sulfur-containing compounds, including allyl methyl sulfide, dimethyl disulfide, and various polysulfides and isothiocyanates. GC-SCD chromatograms revealed four additional sulfur species masked in GCMS total ion chromatograms due to peak overlap. Enhanced selectivity facilitated clear resolution of coeluting analytes, confirming the synergy between detectors.

Benefits and Practical Applications

• Elevated Sensitivity: Selective detection of sulfur odorants at trace levels.
• Comprehensive Profiling: Broader compound coverage through complementary detectors.
• Quality Control: Improved assessment of food freshness, spoilage, and flavor quality in research and industrial QA/QC settings.

Future Trends and Potential Applications

Advancements may involve miniaturized or portable GC-SCD modules, integration with time-of-flight or high-resolution mass spectrometry, and applications in environmental odor monitoring, fragrance development, and metabolomics. Data-driven algorithms and machine learning could further refine compound identification and odor profiling.

Conclusion

Integrating GCMS and GC-SCD effectively enhances detection and identification of sulfur-based odorants in food matrices. This dual approach overcomes limitations of conventional GCMS, enabling robust and sensitive analysis of trace sulfur compounds crucial for flavor and quality evaluation.

Reference

Application Note No. M289, Shimadzu Corporation, February 2020.