The optimized HS-GC-MS was validated according to the guidelines reported by Green (Green, 1996) in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy. The linearity of the calibration curve was evaluated from 5 to 1200 ng in the headspace vials by plotting the peak area ratio of furan/d4-furan. The calibration data are summarized in Table 1 showing good linearity