AOAC SPDS Meeting Book March 19 2015

Challenges  Chemical differentiation of oolong tea and black tea/orange pekoe tea  Variation of tea catechins content due to • Different geographic locations • Seasonal changes • Different processing methods of tea products • Different extraction methods • Different solvents  Interference from other ingredients.

Existing Methods – General Literatures • HPLC (UPLC) UV‐MS: Identification and quantitation  catechins, caffeine, flavonoids, phenolics, amino acids • HPTLC: Identification  • NMR: Metabolic Profiling • FTIR and NIR: Identification, Differentiation 

• GC: Aroma and flavor • UV: Total polyphenols