Meat analysis: Method validation for boar taint analytics by SPME-GC/MS

Significance of the Topic

The prevention and reliable detection of boar taint are critical in modern pork production, particularly as the upcoming ban on surgical castration without anaesthesia drives interest in alternative management strategies. Accurate quantification of the key odour-active compounds—androstenone, skatole and indole—in adipose tissue is essential for ensuring product quality and consumer acceptance. An efficient, solvent-free sampling and enrichment technique such as headspace solid-phase microextraction (HS-SPME), coupled to gas chromatography/mass spectrometry (GC/MS), offers a rapid and sensitive approach suitable for routine screening in research and industrial laboratories.

Objectives and Overview of the Study

The primary goal of this work was to validate an HS-SPME-GC/MS method for simultaneous determination of the three principal boar taint compounds in fat samples, using deuterated internal standards. A key focus was the systematic evaluation of six different SPME fiber coatings to identify the most effective phase for extracting both polar and non-polar analytes under identical headspace conditions.

Methodology and Used Instrumentation

• GC/MS: Shimadzu GC-2010 Plus coupled with GCMS-QP 2010 Ultra
• Autosampler: Shimadzu AOC-5000 with PAL System PAL-xt
• Column: Macherey-Nagel Optima 5 HT, 30 m × 0.32 mm i.d., 0.1 µm film
• Carrier gas: Helium 5.0; injector temperature 270 °C; splitless mode
• SPME fibers tested: PDMS/DVB, PDMS (7, 30, 100 µm), polyacrylate (85 µm) and Carbowax/divinylbenzene (CWR 95 µm)

Laboratory standards of androstenone, skatole, indole, p-cresol and 2-aminoacetophenone were prepared in methanol, spiked into headspace vials along with deuterated analogues as internal standards. Equilibration and extraction were carried out at 100 °C, with 5 min pre-equilibration and 30 min extraction, followed by 20 min thermal desorption in the GC inlet. Quantification relied on selected ion monitoring of characteristic m/z transitions.

Main Results and Discussion

Extraction efficiency varied markedly with fiber polarity and coating thickness. Non-polar PDMS fibers yielded low response for the polar indole, skatole and p-cresol, despite showing strong androstenone signals that scaled with film thickness. The polar polyacrylate fiber improved recovery of polar analytes but did not maximize androstenone. The mixed Carbowax/DVB fiber with a 95 µm coating (CWR 95/10) achieved the best compromise, delivering the highest peak areas for indole, skatole and p-cresol, while maintaining strong androstenone extraction and consistent internal standard performance. Reproducibility across five replicates was within acceptable limits for all analytes.

Benefits and Practical Application of the Method

The validated HS-SPME-GC/MS approach is solvent-free, minimizes sample handling and cross-contamination risks, and is readily automated for high throughput. Its sensitivity and selectivity enable reliable monitoring of boar taint markers at trace levels in routine quality control, breeding trials and research on alternative castration methods.

Future Trends and Opportunities

• Integration with fast GC and high-resolution MS for even shorter runtimes and enhanced selectivity.
• Development of robust calibration protocols for complex matrices and co-extracted lipids.
• Implementation of portable SPME-GC/MS systems for on-site screening at abattoirs.
• Exploration of novel fiber chemistries targeting other potential odorants beyond the three classic markers.

Conclusion

The Carbowax/DVB SPME fiber (CWR 95/10) emerged as the optimal coating for simultaneous extraction of boar taint compounds in adipose tissue under standardized HS-SPME-GC/MS conditions. The method combines simplicity, sensitivity and reproducibility, satisfying the demand for reliable boar taint analytics in both research and industrial quality assurance.

References

• EFSA. Welfare aspects of the castration of piglets. EFSA-Q-2003-091, 2004.
• Dijksterhuis, G.B. et al. International study on androstenone and skatole in boar taint. Meat Sci. 54:261–269 (2000).
• Pawliszyn, J. Solid Phase Microextraction – Theory and Practice. Wiley-VCH, 1997.
• Fischer, J. New methods for quantifying boar taint compounds. Shaker Verlag, 2013.
• Arthur, C. & Pawliszyn, J. SPME with thermal desorption. Anal. Chem. 62:2145–2148 (1990).