Determination of Cadmium in Saudi Arabian Imported Green Tea Samples By ICP-MS

Author(s): Seham A. Al-Ansi, Ahmed A. Othman and Mohammed A. Al-Tufail

Cadmium (Cd) in nine different Saudi Arabian imported green tea samples originated from China has been determined using inductively coupled plasma mass spectrometry (ICP-MS). Tea infusion and microwave acid digestion procedures are used for sample pre-treatment. Infusion is prepared from 2.0 g of tea samples in 100 mL boiled distilled and de-ionized water, digestion is performed with 25% (v/v) nitric acid. Samples are diluted 50 times with 1.0% (v/v) nitric acid solution which contain rhodium as an internal standard before aspiration into ICP-MS. The method showed, limit of quantification of 0.001 mg/L, 0.001 – 0.200 mg/L linearity range (r = 0.9999) and relative standard deviation (% RSD) value for reproducibility (inter-day precision) of 19%. The concentrations range of cadmium (total) in the analyzed green tea samples is 0.081 - 34.295 mg/kg. The total concentration of cadmium released 2% - 20% into tea infusions with boiling water. The calculated average daily intakes of cadmium in tea infusions was low and within the bounds of safety (< 0.001 mg/kg/day).

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