Figure 1. GC × GC/TOF-MS chromatography 3D plot of the extracts of Luzhoulaojiao liquor L9 extracted by liquid-liquid extraction (a) and solid-phase microextraction (b).

The 1st dimension time is the retention time in the vapor pressure dimension and the 2nd dimension time is the retention time in the medium dimension, and the plots of abundant compound were red while the ones with low concentration were blue. A larger number of peaks were detected from the extracts by LLE than that by SPME. By performing SPME, some peaks invisible using LLE could be detected due to the specificity of the fiber. Usage of SPME and LLE can facilitate comprehensive chemical analysis in the Luzhoulaojiao liquor.