Recent Research Advancements of Coffee Quality Detection: Targeted Analyses vs. Nontargeted Fingerprinting and Related Issues

Table 2

Key parameters in liquid and gas chromatography.

Key characteristics	LC	GC
Targeted compound	Relative molecular mass is large (1000–2000), high boiling point, and difficult to volatilize	Relatively small molecular mass (<1000), low boiling point, and volatile [60]
Columns	Tens to hundreds of millimeters [61]	A few meters to tens of meters and different capillary columns [62]
Mobile phase	Liquids, single or mixed water, acetonitrile, and methanol	Gases, such as H2, N2, Ar, He, and CO2 [63]
Flow rate	≤1.0 mL/min, normally [64]	20–100 mL/min, normally [64]
Detection time	HPLC > UPLC	A few to tens of minutes
Detector	Ultraviolet detector (UV-detector), mass spectrometry (MS), diode array detector (DAD), fluorescence detector (FLD), and refractive index detector (RID) [65]	Flame ionization detector (FID), thermal conductivity detector (TCD), electron capture detector (ECD), flame photometric detector (FPD), nitrogen phosphorus detector (NPD), and MS [63, 66]
Others	Room temperature detection, using a flat-headed injection needle	In the gasification chamber gasification, higher detection temperature, using a pointed injection needle