Abstract: The contents of cadmium in tea samples including green tea, oolong tea, jasmine tea, and Pu,er tea were determined using microwave digestion followed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The linear range was from 0 to 100μg/L (R2 = 0.9998). The limit of detection (LOD) for cadmium was 1.88μg/L. The spike recovery was ranged from 95.7% to 102.3% with a relative standard derivation (RSD) of 1.1%. In conclusion, the method is a rapid, convenient, and highly sensitive method to determine cadmium content in tea samples. The contents of cadmium in randomly sampled forty tea samples were between 0.017 mg/kg and 0.138 mg/kg with an average of (0.082±0.028) mg/kg. The average content of cadmium in green tea showed a significant difference when compared with other tea samples (P＜0.05).

Key words: tea, cadmium, microwave digestion, inductively coupled plasma atomic emission spectroscopy (ICP-OES)