Determination of Heavy Metals and Lanthanides in Indian Tea by Inductively Coupled Plasma Mass Spectrometry (ICP-MS)

In the present work, six heavy metals (Mo, Cd, SI), TI, Pb, and Bi) and eight lanthanides (12, Ce, Pr, Nd, Sm, Gd, Dy, and Yb) were determined at ng g(-1) levels in 77 Indian tea samples using inductively coupled plasma source mass spectrometry (ICP-MS) after microwave digestion of the solid samples. The samples included virgin tea leaves and processed tea samples collected from tea-producing regions as well as some commercially available in the market. The analytical procedure was validated by analyzing the certified reference material GSB-7 Tea Leaves. The results of the present work show that the heavy metal and lanthanide concentrations in tea samples from India, present at ng g-1 levels, are comparable to tea obtained from other tea-producing regions in the world. Due to the low extraction efficiency of heavy metals and lanthanides, their daily limit of intake was found to be below the WHO permissible intake values (Cd 11 ng/day, Mo 24.2 ng/day, Sb 6.4 ng/day, TI 18-75.7 ng/day, PI) 200-300 ng/day, and Bi 8-16 ng/day). The significant differences in the elemental concentration of heavy metals and lanthanides from the different tea-producing regions give an indication of the different degree of pollution in these regions.