Abstract
The levels of some selected essential, non-essential, toxic elements and water-soluble inorganic anions (WSIAs) leached from green tea (GT) leaves infusion in boiled water at various time breaks were determined. A number of 29 GT samples were analyzed by Inductively Coupled Plasma-Mass/optical emission Spectrometry (ICP-OES/MS) and Ion chromatography (IC). The levels of studied elements and WSIAs (F-, Cl-, NO3-, PO (3-)(4) and SO42-) leached from GT leaves in boiled water increased on growing infusion time. Chemical speciation (labile and complexed fractions) of P, Al, Cu, Pb and Cd in GT leaves in boiled water was estimated. At 95% confidence level (P > 0.50), the student t-test values as calculated for essential and toxic metals were smaller than the critical value indicating no significant differences between element concentrations in the tested samples. The average daily dietary intake (ADDIs) for selected elements and the average daily intake (ADI) and the chronic reference dose (RFD) for Cd (mu g kg(-1) BW day(-1)) were critically determined. Evaluation of inorganic composition allows quantification of the leaching percentage and the hazard beyond provisional acceptable average daily intake (ADI) values.
Practical applications: WSIAs plays a significant role in green tea quality monitoring. Calculation and speciation of the mineral configuration and selected elements of GTs is of prime importance to evaluate the intake of hazard metals and biocomponent associated with the eating of infusions. Therefore, the levels of WSIAs leached in boiled tea infusions using IC and ICP-OES/MS were determined. However, the number of GT samples and their origins are limited. The work clearly indicated that, the differentiation and classification of tea samples from various provinces in many countries could be possible employing pattern recognition and analytical techniques. The levels of the elements K, P, Si, Fe, Cu, Al, Pb and Cd may be used as appropriate descriptors for identification of GTs origin.