Determination of lead by hydride generation atomic absorption spectrometry with in situ, concentration in a zirconium coated graphite tube

A method is described for the determination of lead by the in situ concentration of lead hydride on a Zr coated graphite tube with subsequent detection by electrothermal atomic absorption spectrometry. The method gives a six-fold enhancement of sensitivity with respect to that using a pyrolytic graphite coated graphite tube for the sorption of lead hydride. The characteristic mass (i.e., the mass of analyte which provides a defined peak absorbance of 0.0044 A) is 52.8 pg. The relative standard deviation for ten replicate measurements is 2% at the level of 3 ng of lead. An absolute detection limit (3σ) of 242 pg is obtained. The proposed method has been applied successfully to the determination of lead in some reference materials and a tap water sample.