Study of matrix effects and spectral interferences in the determination of lead in sediments, sludges and soils by SR-ETAAS using slurry sampling

MARIANELA SAVIO; SOLEDAD CERUTTI; LUIS D. MARTINEZ; PATRICIA SMICHOWSKI; RAÚL A. GIL

TALANTA

ELSEVIER SCIENCE BV

Año: 2010 vol. 82 p. 523 - 527

0039-9140

An interference-free, fast, and simple method is proposed for Pb determination in environmental solidsamples combining slurry sampling and electrothermal atomic absorption spectrometry. Samples wereground to an adequate particle size and slurries were prepared by weighing from 0.05 g to 0.20 g ofdry sediment, adding nitric acid, and a solution containing 0.1% Triton X-100. Ultrasonic agitation wasemployed for slurries homogenization. Analytical variables including acid pre-treatment conditions, particlesize, slurry stability, temperature program of the graphite furnace, and type and concentrationof the chemical modifier were studied. The undesirable effects of potential non-specific and spectralinterferences on Pb signal were also taken into account. Continuum source and self-reversal methodsfor background correction were evaluated and compared. For calibration, synthetic acid solutions of Pbwere employed. Calibration was linear within the range 1 30gL-1 and 5 30gL-1 when the 217.0nmand 283.3nm analytical lines were used. Correlation coefficients of 0.9992 and 0.9997 were obtained.Using optimized conditions, limits of detection (3S) of 0.025gg-1 and 0.1gg-1 were achieved for the217.0nm and 283.3nm analytical lines, respectively. The method was successfully applied to the determinationof lead in soil, contaminated soil, municipal sludge, and sediment samples. The accuracy wasassessed by the analysis of two certified reference materials: municipal sludge (QC MUNICIPAL SLUDGEA) and lake sediment (TRAP-LRM from IJS).