Determination of Estragole in Fennel Herbal Teas by HS-SPME and GC–MS

Abstract

Estragole, a volatile phenylpropanoid contained in a variety of edible herbs, has been demonstrated to be genotoxic and carcinogenic, and its addition as a flavoring substance to foodstuffs has been banned by the regulatory bodies of the European Union. Fast and accurate analytical methods for its determination in herbs are thus necessary to assess the dietary exposure of this substance in humans and, in particular, to sensitive groups. In the present study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography–mass spectrometry (GC–MS) was applied for determination of estragole in infusions from different widely used commercial herbal teas based on Foeniculum vulgare (fennel) seeds. The optimized HS-SPME extraction conditions involved the use of a polydimethylsiloxane fiber exposed to the herbal infusion for 20 min at 50°C followed by GC–MS analysis. The method was fully validated for linearity, sensitivity, accuracy, and precision and applied to real samples; the level of estragole in infusions of commercial fennel seed teas was found to be within 50–250 µ`⁻¹.

Keywords:

• Estragole
• Gas chromatography–mass spectrometry
• Herbal teas
• Solid phase microextraction

Acknowledgments

The authors wish to thank Uni Rimini SpA for supporting the present work. This work was supported by Regione Emilia Romagna, Italy (Funding POR FESR 2007–2013).

Notes

^a Sample type as reported in Table 1.

^b Estragole concentration spiked to the commercial samples.

^a Sample type as reported in Table 1.

^b Intraday precision (n = 6).

^c Inter-day precision (n = 18).