A two-run heart-cut multidimensional gas chromatography method using flame ionization and mass spectrometry for automated and robust determination of nearly complete wine aroma-volatile profiles

A quantitative analytical method capable of determining the concentrations of 81 aroma-relevant wine volatiles covering nine orders of magnitude was developed and validated in this study. The method is based on stir bar sorptive extraction (SBSE) of 200 mu L of wine diluted with 1.8 mL NaCl brine with pH 3.5. Volatiles thermally desorbed from the stir bars were separated in two runs in a heart-cut multidimensional gas chromatographic system and quantified using either a flame ionization detector (FID) in the first dimension (27 aroma compounds) or a mass spectrometer in the second dimension (54 aroma compounds, transferred to 22 cuts). Typical limits of compound detection lay around 0.02 mg/L by FID or ranged from 0.001 to 0.30 mu g/L by mass spectrometry detector, liying below the corresponding odor thresholds in all cases. Linearity, reproducibility, and recovery were considered satisfactory for most compounds, with typical R2 values of 0.989-0.999, relative standard deviation below 10 % for 37 compounds and between 10 and 20 % for 44 compounds, and recovery rates of approximately 100 % (85-109 %) for all but acetaldehyde. An analysis of 20 wine samples completed our validation of the method, showing that a single-sample preparation procedure combined with heart-cut multidimensional two-detector gas chromatography can determine wine volatile concentrations ranging from 350 mg/ L of isoamyl alcohol to 3.8 ng/L of 3-isobutyl-2-methoxypyrazine.

Automated summary

A quantitative analytical method was developed and validated in this study to determine the concentrations of 81 aroma-relevant wine volatiles. The method utilizes stir bar sorptive extraction and multidimensional gas chromatography with flame ionization detector or mass spectrometer. The method demonstrated good linearity, reproducibility, and recovery, and was successfully applied to analyze 20 wine samples.