Determination of lead in drinking water by atomic-absorption spectrophotometry with electrothermal atomisation

Abstract

The use of electrothermal atomisation to determine concentrations of lead in water, although sensitive, generally suffers from suppressive interference effects that can produce large and variable negative bias. This paper describes a procedure that employs a lanthanum pre-treatment technique, which when tested with a range of 14 drinking water samples is shown to overcome such interference. The pre-treatment technique can be either impregnation of the furnace tube with lanthanum or the addition of lanthanum (as lanthanum chloride) to each sample. The procedure has a limit of detection of less than 1.0 µg l^–1, a total standard deviation of less than 1.5 µg l^–1, or 5% of the concentration, and a bias of less than 5 µg l^–1, or 10% of the concentration over a working range of 0–100 µg l^–1, for both manual and automated injection of samples.