Determination of lead in natural and tap waters by flame atomic-fluorescence spectrometry

Abstract

A simple and rapid method is described for the determination of lead in water using a flame atomic-fluorescence system. The sample is acidified (1% nitric acid), prior to direct aspiration into a nitrogen-shielded air-hydrogen or air-acetylene flame of a purpose-built atomic-fluorescence spectrometer. The preparation and operation of the lead electrodeless discharge lamps used as the excitation source have been optimised by a five-factor simplex procedure. A routine detection limit of 2.5 µg l^–1 has been achieved regularly for lead in aqueous solution with the air-hydrogen flame, and 7 µg l^–1 with the air-acetylene flame. No significant chemical interferences were observed from a wide range of other cations and anions, and automatic background correction for scattered radiation was achieved using a continuum light source. Aqueous standards were used for calibration. The precision of the method was ascertained and accuracy established by satisfactory standard additions and recovery experiments and by comparison with results obtained by other methods.