Determination of lead in calcium carbonate by flow-injection hydride generation with dc plasma atomic emission detection

Flow-injection hydride generation, coupled with de plasma atomic emission spectrometry has been used for the determination of trace lead concentrations in calcium carbonate matrices. The use of ferricyanide combined with sodium tetrahydroborate(III) enable the production of plumbane from acid solution. The plumbane is separated in a new gas-liquid separator and delivered to the plasma for determination. Detection limits for the technique are 0.7 ng ml(-1). Precision of measurements at the 20 ng ml(-1) level was 1.6% RSD. In an investigation of interferences, it was found that Fe(II), Fe(III), Cd(II), Co(II), Mn(II), Ni(II) and Zn(II) do not interfere. The presence of copper(II) at 1 mu g ml(-1) reduced the signal from lead by 50%. Samples can be analyzed at a rate greater than 60 h(-1). (C) 1998 Elsevier Science B.V. All rights reserved.