Interference Mechanism of Sulfate Matrices in Graphite Furnace Atomic Absorption Spectrometry for Lead

Although graphite furnace atomic absorption spectrometry is favorable for the analysis of trace amounts of lead, severe matrix interferences of various sulfates on the sensitivity of lead have been reported. "2 Frech et a1.3 reported the distribution of lead in various species in the presence of sulfur by the theoretical equilibrium calculations and pointed out that the interference effect from sulfur should be strong. Although the interference effect of sodium sulfate on the atomic absorbance of lead was strong, the interference mechanism was not explained.1 In this work, as lead atomic absorption was measured in nitrates and sulfates of zinc, copper, magnesium, aluminum, nickel and cobalt, different matrix effects were observed between the nitrate and the sulfate matrices. This investigation provides a mechanism of the interference effect from sulfur.