Table 2.

Advantages and disadvantages of GC, HPLC, and their derivative methods to analyze VVOCs.

Methods		Advantages	Disadvantages	References
GC and its derivative methods	GC	Simply, sensitively and efficiently separate and detect VVOCs.	High cost when using expensive standard, and not suitable to determinate compounds with poor thermal stability	Murray, 2001; Bartle and Myers, 2002; Marín et al., 2002; Yu et al., 2012; Chen et al., 2013a; Chauhan et al., 2014; Zhou et al., 2017, 2020; Song and Liu, 2018
	GC-MS	Qualitatively and accurately describe the VVOC profiles from the different vinegar samples according to robust available GC-MS databases.	Contribution of each VVOC to the overall aroma and flavor of vinegar and the characteristic aroma-active and odor-active compounds cannot be detected.
	SPME-GC-MS	Automatically absorb and concentrate VVOCs, avoid loss and pollution of VVOCs in sample pretreatment, and cut down sample preparation time, solvent usage and disposal costs.	Some VVOCs, such as acetoin, cannot be accurately detected owing to that the fibers are not sensitive to them.
	GC-O	Directly determine key aroma active VVOCs, especially those with high odor intensities but the low concentration via the olfaction systems, such as the human olfactory or the olfactometric detectors.	Not efficient for the qualitative analysis of VVOCs.
	GC-O-MS	Simultaneous detection of aroma-active VVOCs and acquisition of their corresponding chemical structural information due to combination of MS and olfactometric detector.	The working conditions may AFPfect the synchronization of the retention time of VVOCs in MS and the olfactometric detectors.
	HS-SPME-GC x GC-TOMS	A very powerful and effective technique to analyze VVOCs due to high resolution, high sensitivity, high peak capacity and structured chromatograms, and especially qualitatively differentiate ions with similar m/z.	The standard mass spectrometry library is not rich enough, and it needs better and faster data processing software to treat huge data produced by HS-SPME-GC x GC-MS. High costs and careful maintenance are need.
HPLC and its derivative methods	HPLC	A rapid, easy and precise separative and quantitative method for VVOCs with poor volatility and poor thermal stability.	Low sensitive and not suitable for some VVOCs.	Theobald et al., 1998; Yan and Wang, 2013; Wu et al., 2019
	DLLME-HPLC	A method with good sensitiveness, accuracy, short process and small wastes.	The extract solvents, such as chlorobenzene, chloroform, carbon tetrachloride and carbon disulfide, are toxic and harmful to the environment.