Determination of trace amounts of copper and lead in water by flameless atomic absorption spectroscopy

Abstract

Direct determination of trace amounts of copper and lead in water was investigated by flameless atomic absorption spectroscopy using a carbon tube atomizer. A sample solution (20μl) was atomized by passing a high electric current through the atomizer. The concentrations of copper and lead were calculated directly from the calibration curves by measuring the absorption peak heights of copper at 324.7 nm and of lead at 283.3 nm.The absorbances of copper and lead were decreased by the addition of high concentrated acids. The absorbance of copper was decreased by the addition of 1000-fold silver, barium, lithium, and strontium, and that of lead was also decreased by the addition of 1000-fold silver, barium, cobalt, lithium, mercury, and strontium. The background absorption such as molecular absorption and light scattering of a matrix salt was corrected by measuring the absorbance of the salt at the non-resonance line.This method was applied to the direct determination of trace amounts of copper and lead in river water and industrial waste water. The analytical results were in good agreement with those obtained by a method of atomic absorption combined with a solvent extraction. The limits of detection were 0.2 ppb of copper and 0.4 ppb of lead when the signal to noise ratio was 2. The coefficients of variations were less than 4% in both determinations.