Determining Phenolic Compounds in Whisky using Direct Large Volume Injection and Stir Bar Sorptive Extraction

In this study, a method was developed for quantitative determination of seven phenolic compounds in scotch whisky. Two different whisky brands were analyzed by Stir Bar Sorptive Extraction (SBSE), based on novel EG-Silicone Twisters, combined with thermal desorptiongas chromatography-mass spectrometry (TD-GC-MS). Direct Large Volume Injection (LVI) -GC-MS was used as reference method. Optimized methods for LVI-GC-MS and SBSE-TD-GC-MS analysis were used for quantitative determination of the target compounds: phenol, o-,m-, and p-cresol, guaiacol, 4-ethylguaiacol, and 4-ethylphenol. Both methods were evaluated regarding linearity of calibration, reproducibility, and limits of detection (LOD), or limits of quantifi cation (LOQ), for the target compounds. These values were calculated for pure whisky (40 % v/v, ethanol/ water). Target compound LODs for the SBSE-TD-GC-MS method range from 1.2 ng/mL (guaiacol) to 6.9 ng/mL (4ethylguaiacol) based on extraction of 5 mL ethanol/water sample. LODs of LVI-GC-MS range from 90 ng/mL (phenol) to 210 ng/mL (4-ethylguaiacol) based on injection of 20 μL ethanol/water sample. Coeffi cients of determination (R2) for the calibration curves were found to be higher than 0.999 for the SBSE-based method and between 0.991 and