Determination of trace elements in medicinal activated charcoal using slurry sampling electrothermal vaporization...

The determination of Cd, Sb, Te, Hg, Tl and Pb in medicinal activated charcoal by ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) was described. EDTA was used as the modifier to enhance the volatility of elements studied. The influences of instrument operating conditions and slurry preparation on the ion signals were studied. A relatively low vaporization temperature of 1000°C was used, which separated the analyte from the major matrix components that improved ion signals. The method has been applied to determine Cd, Sb, Te, Hg, Tl and Pb in an NIST SRM 1633b Coal Fly Ash reference material and three brands of medicinal activated charcoal capsules using isotope dilution and standard addition calibration methods. The concentrations that are in ng g(-1) levels were in good agreement between different calibration methods. The precision between sample replicates was better than 7% with USS-ETV-ICP-MS technique. The method detection limit estimated from standard addition curves was 0.4, 0.3, 0.3, 0.3, 0.04 and 0.9 ng g(-1) for Cd, Sb, Te, Hg, Tl and Pb, respectively, in original medicinal activated charcoal.