The metal contents of eleven black tea samples, four cultivated in Iran and seven imported, and their tea infusions were determined. Twelve elements consisting toxic metals (Al, As, Pb, Cr, Cd, and Ni) and essential mineral elements (Fe, Zn, Cu, Mn, Ca, and Mg) were analyzed using inductively coupled plasma atomic emission spectroscopy (ICP-AES). Al, Ca, Mg, and Mn ranged in black tea leaves at mg g(-1) levels, while Cr, Fe, Ni, Cu, Zn were at microg g(-1) levels. Analysis of variance showed no statistically significant differences among most elements determined in cultivated and imported black teas in Iran except for Ni and Cu. The extraction efficiency of each element into tea infusions was evaluated. The solubility of measured metals in infusion extracts varied widely and ranged from 0 to 59.3%. Among the studied elements, Cr, Pb, and Cd showed the lowest rates of solubility and Ni had the highest rates of solubility. The amount of toxic metals and essential mineral elements that one may take up through consumption of black tea infusion was estimated. The amount of realizing each element into tea infusions and acceptable daily intake, for safety consumption of black tea, was compared.

A simple, economical and reproducible benzoylation procedure was developed for the derivatization of biogenic amines (BAs) prior to high-performance liquid chromatography determination. The significant factors affecting biogenic amine benzoylation yield were optimized by central composite design. The derivatized BAs were extracted from basic aqueous solutions by 2-undecanol for direct HPLC injection. The obtained optimal conditions significantly decreased reagent consumption, uncertainty and time of analysis. The optimized method was used for further determination of BAs in real samples of nonalcoholic beers. The method showed good linearity (correlation coefficients > 0.997) and good recoveries (from 87.3 to 96.3%). The repeatability and reproducibility of the method were >4.6% and >6.7% respectively. Moreover, the detection limits of BAs were calculated between 0.02 and 0.09 mg ml À1 in non-alcoholic beers samples.

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