Abstract: The geographical traceability of tea from different production areas was studied by gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS) based on carbon and nitrogen stable isotope ratios in caffeine and amino acids. The results showed that GC-C-IRMS combined with compound specific stable isotope ratio analysis could be used to trace the geographical origin of tea. Chemometrics analysis showed that this method could effectively distinguish tea from different production areas, with accuracy of prediction and verification more than 85%. BP artificial neural network had the best authentication performance, with accuracy of prediction and verification of 100%. After further screening and identification, two characteristic marker compounds, δ15Nalanine and δ13Ctheanine, were obtained for Xiuya green tea from different production areas. This study can provide some technical support for geographical traceability of tea and help to establish a sound certification system for tea products.

Key words: tea; geographical traceability; caffeine; amino acids; carbon and nitrogen stable isotope ratios