SESH · ADVANCED FRAGRANCE ACADEMY
Interpret peak-based analytical reports and avoid false claims of complete reverse-engineering.
Follow sample introduction, column separation and detection. This GC schematic is not a SESH perfume test and does not independently establish sensory experience.
Open full-size image ↗Two linked tools, two different jobs
Gas chromatography separates analytes under selected column and temperature conditions, while mass spectrometry supplies ion-fragmentation information to support identification using libraries and standards. A chromatographic peak is not a named perfume note. Less volatile, thermally sensitive or otherwise unsuitable constituents may require different methods and preparation.
What a peak represents
A peak has a retention time and a detector response associated with one or more analytes under specified conditions. Retention time alone is not unique identification; a library mass-spectrum match is often tentative until corroborated by reference standards or orthogonal evidence. Co-elution can complicate assignments.
Peak area is not a universal ingredient percentage
A larger peak area does not automatically equal a larger formulation percentage. Detector responses vary by analyte and sample preparation may alter recoveries. Reliable quantification needs appropriate calibration, internal standards where relevant, validated response factors and uncertainty estimates. An uncalibrated area-percent table is not a complete perfume formula.
Linalool contains an OH alcohol group. One functional group is insufficient to predict every molecule’s odour or the performance of a mixture.
Open full-size image ↗What the chromatogram misses
Constituents may lie below detection limits or outside the chosen analytical method. Trace odorants can matter disproportionately to smell. GC-MS does not automatically reveal blending order, accord design or sourcing. Detecting linalool alone cannot prove whether it was plant-derived or synthetically produced.
Make a bounded analytical conclusion
A hypothetical 20-peak report can support tentative constituent identification and controlled comparison between similarly prepared samples. It cannot establish a 100% proprietary formula or universal natural origin. Document the method, sample prep, calibration, detection limits and identification confidence. Analytical evidence complements sensory evaluation rather than replacing it.
Case study: the dominant peak may not dominate odor
A hypothetical chromatogram shows a much larger peak for A than for B, yet panelists report an odor character associated with B. Detection thresholds and odor impact can explain the discrepancy. Detector response and sensory dominance are different measurements.
Practical desk-based exercise
Interpret four hypothetical GC-MS peaks. For each, state identification certainty, whether quantitative calibration exists and whether sensory significance is established or speculative.
Three diagrams summarizing the lesson
GC-MS analytical sequence
- Suitable sample preparation
- GC: chromatographic separation
- MS: mass-spectrum evidence
- Interpret with standards and calibration
Three peak misconceptions
- Peak ≠ marketed perfume note
- Peak area ≠ automatic concentration
- Library match ≠ conclusive identity
Boundaries of reporting
- Detection limit and preparation
- Compounds outside method range
- Origin not automatically known
- Odor impact not automatically proved
Scientific terms
- Retention time
- Time an analyte takes to elute from a column under defined conditions.
- Mass spectrum
- Ion pattern that helps support compound identification.
