Assessment of palladium nanoparticles as chemical modifier for lead determination in leached extracts from petroleum waste by high-resolution continuum source atomic absorption spectrometry

Abstract

ABSTRACT Palladium nanoparticles were evaluated as a potential chemical modifier for lead determination by high-resolution continuum source graphite furnace atomic absorption spectrometry. Hydrophilic palladium nanocubes and palladium nanospheres were synthesised with sizes varying from 3 to 22 nm. Positive effects in terms of sensitivity and thermal stability upon the use of palladium nanoparticles were observed, especially using the 3 nm spherical-shaped. The mass of modifier influenced the thermal stability and relative signal intensity of the analyte, although the effectiveness of the modifier appeared to be suppressed to an important extent in the presence of matrix components of the leached extracts obtained from petroleum wastes. The optimised pyrolysis and atomisation temperatures were, respectively, 800 °C and 2300 °C, using 200 ng of 3 nm palladium nanoparticles. The limit of detection (4 µg L−1) and the precision (better than 18 %) were considered satisfactory for the proposed analysis. The method accuracy, evaluated by recovery tests and by comparison with the results obtained using inductively coupled plasma mass spectrometry, was proven adequate to enable the determination of Pb in leached extracts from petroleum waste. The method was successfully applied to determine lead in leached extracts obtained from oily sludge and drill cuttings and the obtained concentrations ranged from <13 to 354.4 µg L−1.