Research progress in identification method of Pu- erh tea

Fourier transform infrared spectroscopy( FTIR),Near infrared spectroscopy( NIRS),Nuclear magnetic resonance spectroscopy( NMR),Reverse phase- high pressure liquid chromatograph( RP- HPLC),Raman spectroscopy( Raman) Surface desorption atmospheric pressure chemical ionization source- mass spectrometry( SDAPCI- MS),Atomic absorption spectrometry( AAS),Simultaneous distillation extraction( SDE),Gas chromatograph- mass spectrometry( GC- MS),Electronic tongue( ET) and other identification methods of tea were cited in this text.The changes in the active substance content of different years and different regions of tea were demonstrated in this paper. The different effective substances between pu- erh tea and other tea were also expounded to readers,which would lay the foundation for identifications of Pu- erh tea.