Automated and quantitative headspace in-tube extraction for the accurate determination of highly volatile compounds from wines and beers.

摘要: Abstract An automatic headspace in-tube extraction (ITEX) method for the accurate determination of acetaldehyde, ethyl acetate, diacetyl and other volatile compounds from wine beer has been developed validated. Method accuracy is based on nearly quantitative transference sample to ITEX trap. For achieving that goal most methodological aspects parameters have carefully examined. The vial sizes trapping materials were found be critical due pernicious saturation effects ethanol. Small 2 mL vials containing very small amounts (20 μL 1:10 diluted sample) a trap filled with 22 mg Bond Elut ENV resins could guarantee complete vapors. requires 100× 0.5 mL pumping strokes at 60 °C takes 24 min. Analytes are further desorbed 240 °C into GC injector under 1:5 split ratio. proportion analytes finally transferred ranged 85 99%. validation showed satisfactory figures merit. Determination coefficients better than 0.995 in all cases good repeatability was also obtained (better 7% cases). Reproducibility 8.3% except acetaldehyde (13.1%). Detection limits below odor detection thresholds these target well normal ranges occurrence. Recoveries not significantly different 100%, case acetaldehyde. In such it determined able break some adducts this compound forms sulfites. However, problem avoided after incubating glyoxal. can constitute general reliable alternative analysis difficult matrixes.