Accurate Determination of 2,4,6-Trichloroanisole in Wines at Low Parts Per Trillion by Solid-Phase Microextraction Followed by GC-ECD

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Abstract
A headspace solid-phase microextraction (HS-SPME) procedure at 30 °C with a 100 μm PDMS fiber of a saturated NaCl solution stirred at 1100 rpm combined to GC-ECD for the 2,4,6-trichloroanisol (TCA) determination in wines has been developed. Due to the matrix complexity and ethanol absorption into the fiber, the internal standard selection was crucial to obtain unbiased results. Thus, matrix effects were observed when analyzing different types of Spanish wines (white, early, and vintage red wines) spiked with TCA at low concentration levels (i.e., -1). In contrast, the use of 2,4,6-tribromoanisole (TBA) as internal standard overcame these matrix effects, whereas the use of 2,4,6-trichlorophenyl ethyl ether led to inconsistent results. The developed HS-SPME-GC-ECD methodology reaches a limit of quantitation for TCA in wine within 2.9−18 ng L-1, with a relative standard deviation of 2.5−13.4%, depending on the TCA concentration level and wine characteristics. This analytical method is comparable to the existing methodologies based on HS-SPME followed by GC-MS in terms of accuracy, precision, length of determination, and length of quantification; however, analysis cost is reduced. Keywords: SPME-headspace; TCA; GC-ECD; internal standard selection; wine; matrix effect; musty odor