PURPOSE:To highly precisely determine Pb without the use of an organic extraction solvent, by a method wherein Pd is dissolved in a solution in which a sample is dissolved by acid, the Pb in the solution is then coprecipitated togetherwith the Pd through reduction of the solution, and only the Pb in sediment is dissolved by acid to perform an atom absorbance analysis. CONSTITUTION:In an atom absorbance analysis of Pb in steel, a Zn alloy, a sample is dissolved into acid, such as aqua regia by an oxidizing acid, such as HClO4, and after it is condensated until salt is separated out, it is cooled, filtered, and washed by water, a citric acid solution and Pd as an opacifying agent and sodium formate as a reducer are added to a total of a filtering liquid and a washing water, and the mixture is adjusted to pH5 to bring an overflow capacity into a fixed capacity. The solution is quietly boiled to separate the Pd into a metallic shape, and simultaneously, the Pb is allowed to agglomerate and settle. The sediment is filtered, it is washed by water, and the Pb is dissolved through addition of nitrate and HClO4 to the sediment at each filter paper. If a crystalline deposition is made after cooling, the work is dissolved by heating after adding aqua regia and is cooled to bring it into a fixed capacity. A fixed capacity is then collected to perform an atom absorbance analysis. This permits the micro-Pb to be determined highly precisely.
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