Determination of Lead(II) by Electrothermal Atomization Atomic Absorption Spectrometry after Coprecipitation with Gallium(III) Phosphate

Gallium(III) phosphate coprecipitates quantitatively 0.1-2.0 μg of lead(II) from 100-500 cm³ of a sample solution at pH 2.5 - 6.0. The coprecipitated lead(II) can be sensitively determined by electrothermal atomization atomic absorption spectrometry without any influence of gallium(III) phosphate. The calibration curve is linear from 4 to 80 ng cm^-3 for lead(II). The detection limit (signal/noise =2) is 0.095 ng cm^-3 of lead(II) in 500 cm³ of the initial sample solution. Thirty-four diverse ions tested did not interfere seriously with the determination of lead(II). This method was successfully applied to the determination of lead(II) in tap and river water.