Sample testing: participants analyze blind samples using GC-MS or FTIR data

Here’s a detailed framework for a sample testing session using blind samples in an Oud Quality Assessment Course:

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1. Objective

• Train participants to identify authentic vs. synthetic or adulterated Oud using chemical data.
• Develop skills in chromatogram interpretation, peak assignment, and comparative analysis.
• Promote critical thinking, accuracy, and reproducibility in lab assessments.

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2. Preparation of Blind Samples

Step	Details
Sample Selection	Include a variety of samples: high-grade authentic, low-grade, diluted, and synthetic-mimicked oils or chips
Coding / Blinding	Assign a random alphanumeric code to each sample (e.g., B-01, B-02, etc.)
Data Generation	Acquire GC-MS or FTIR spectra for each sample in advance or provide pre-recorded chromatograms/spectra
Distribution	Ensure participants cannot identify samples by appearance or scent during the initial chemical analysis

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3. Analytical Task for Participants

1. GC-MS Analysis (for volatile compounds)
   • Identify major sesquiterpene peaks: α-Guaiene, δ-Guaiene, Agarospirol, etc.
   • Compare peak ratios to reference data.
   • Detect synthetic markers: guaiacol, isoeugenol, vanillin.
   • Note any solvent residues or unusual peaks.
2. FTIR Analysis (for functional group fingerprinting)
   • Identify characteristic O-H, C=O, C=C, and CH2/CH3 stretches.
   • Detect abnormal peaks indicative of adulteration.
   • Compare spectra to reference authentic Oud spectra.
3. Comparative Analysis
   • Match blind samples against reference profiles.
   • Classify as: Genuine, Low-grade, Synthetic, or Adulterated.
   • Record confidence level in identification.

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4. Evaluation Metrics

Criterion	Scoring / Weight
Accuracy of Peak Identification	25%
Detection of Adulteration / Anomalies	25%
Comparative Analysis / Classification	25%
Report Clarity & Justification	25%

Optional: Include time efficiency and peer discussion contribution as bonus points.

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5. Reporting Format for Participants

Sample Analysis Table:

Sample Code	Identified Sesquiterpenes	Chromones Detected	Synthetic / Adulteration Indicators	Classification	Confidence Level	Notes
B-01	α-Guaiene, δ-Guaiene, Agarospirol	THPEC, EPEC	None	Genuine	High	Matches ISO 4730 reference
B-02	α-Guaiene	Low chromones	Guaiacol detected	Adulterated	Medium	Suspected synthetic addition

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6. Debriefing / Discussion

• Compare participant classifications with the actual sample identity.
• Discuss common errors, e.g., misidentifying peaks or missing minor chromones.
• Highlight chemical-sensory correlation, if aroma notes are also evaluated.
• Provide guidance on interpreting complex chromatograms and spectra.

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7. Learning Outcomes

By the end of the session, participants will be able to:

1. Correctly read and interpret GC-MS chromatograms and FTIR spectra.
2. Detect adulteration or dilution in blind Oud samples.
3. Apply ISO 4730 chemical benchmarks for authenticity verification.
4. Prepare structured analytical reports for quality assessment.

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