Development and validation of a method for the analysis of halophenols and haloanisoles in cork bark macerates by stir bar sorptive extraction heart-cutting two-dimensional gas chromatography negative chemical ionization mass spectrometry.

ABSTRACT

A method has been developed for the quantitative determination in cork bark macerates of 7 halophenols and 5 haloanisoles with demonstrated or suspected contribution to the cork taint off-flavour. Macerates were extracted with stirbar (20 mm polydimethylsiloxane-coated) sorptive extraction under optimized conditions (pH 3.5, 20% NaCl and 60 min). The bars were analysed by automated thermal desorption, heart-cutting two-dimensional gas chromatography and negative chemical ionization-mass spectrometry. Matrix effects were compensated for by a "matrix matched" calibration curve. Limits of detection were in the range 0.03-0.24 ng L-1, below the corresponding odor thresholds. Linearity (0.983 ≤ R2 ≤ 0.998), intra- and inter-day precision (5.4-14.3%) and accuracy (89-126%) were satisfactory. The analysis of 48 natural cork bark samples affected/not-affected bya cryptogamic disease (yellow spot) revealed compositional differences in 2,4,6-trichloroanisole (2,4,6-TCA), 2,4,6-trichlorophenol (2,4,6-TCP) and also in 2,6-dibromophenol, 2,3,4- and 2,4,5-TCP, 2,3,4-TCA and 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP). In addition, the contents of 2,4,6-TCP and 2,4,6-TCA, and 2,3,4,6-TeCP and some TCPs presented strong linear correlations.