Availability of essential elements in Indian and US tea brands

Fifteen different brands of Indian tea leaves and seven US brands of flavoured tea were analysed for Na, K, Mn, Cu and Br by thermal neutron activation analysis (TNAA). Mn was also analysed by spectrophotometric and atomic absorption spectrometry (AAS) methods. In Indian tea, Mn concentration was found to be in the range 371-758 μg/g with a mean concentration of 575 ± 96 μg/g whereas in US tea it was in the range 79-768 μg/g with a mean concentration of 329 ± 231 μg/g. Na and Cu contents were also widely different in tea leaves from India and the USA but K contents were similar in the two tea leaves. Bromine was absent in tea leaves from the USA. Several standard or certified reference materials (SRMs/CRMs), including two tea leaves standards, were also analysed for data validation.