Volatile Phenols: Direct Analysis Using Large-Volume Injection-Online Trapping-Gas Chromatography-Tandem Mass Spectrometry (LVI-GC-MS/MS) and Aroma Contribution to Different Aroma-Type of Baijiu

A robust technique using large-volume direct injection-online trapping coupled with gas chromatography-triple quadrupole mass spectrometry (LVI-GC-MS/MS) was developed for volatile phenol analysis in Chinese Baijiu. The sample (20 μL) was injected into a multimode injector with a fritted deactivated glass liner packed with Tenax resin. The injection parameters were optimized to eliminate interfering compounds and enrich the analytes. The developed method had correlation coefficients with R2 in the range of 0.9994–0.9999, the standard deviations were less than 4%, the limits of quantification (LOQs) ranged from 0.10 to 0.66 μg/L, and recoveries were from 87 to 115% in different Baijiu matrices. The method was further applied to study volatile phenols in Baijiu, and it was demonstrated that the concentrations of p-cresol and m-cresol in strong aroma-type Baijiu were significantly higher than those in other aroma types of Baijiu samples.