Comparison of palladium-magnesium nitrate and ammonium dihydrogenphosphate modifiers for lead determination in honey by electrothermal atomic absorption spectrometry

The aim of the present work was to develop and optimize two procedures for the determination of Pb content in honeys by electrothermal atomic absorption spectrometry without any sample pretreatment. Palladium-magnesium nitrate and ammonium dihydrogenphosphate were used as chemical modifiers. Honey was diluted in water, and hydrogen peroxide, nitric acid, and Triton X-100 were added to minimize the matrix effect. RSD (lower than 10%) and the analytical recovery (98-101%) were acceptable for both methods. Pd-Mg(NO3)2 was the method selected for further direct Pb determinations in honey samples because it presented the best limit of detection (LOD = 1.6 ng g−1). Moreover, this method allowed Pb determination using a calibration graph, instead of an addition graph, which is an important advantage. The direct proposed methods have been applied to the determination of Pb content in representative honey samples from Galicia (NW Spain). The lead concentrations found in the analyzed samples were in the range 1.71-75.0 ng g−1.