Determination of Pb in airborne particulate matter with a heavy matrix of silicon by SR-ETAAS

MARIANELA SAVIO; ROBERTO A. OLSINA; LUIS D. MARTINEZ; PATRICIA SMICHOWSKI; RAÚL A. GIL

MICROCHEMICAL JOURNAL

ELSEVIER SCIENCE BV

Año: 2010 vol. 96 p. 243 - 246

0026-265X

A study is undertaken to monitor Pb levels in airborne particulate matter collected on ash-free glass-fibre filtersfrom urban and industrial areas of Argentina by electrothermal atomic absorption spectrometry with selfreversalbackground correction. For this sample with a heavy matrix of silicon, a simple acid treatment with aquaregia and HF is proposed aimed to minimize contamination and reduce sample treatment steps. Ultrasonicagitation was employed for sample homogenization. To overcome the problem of the high amounts of Si, mainanalytical variables including acid pretreatment conditions, temperature program of the graphite furnace andspectroscopic conditionswere carefully studied and optimized. Continuumsource and self-reversalmethods forbackground correctionwere compared in order to avoid non-specific and spectral interferences due to thematrix.After optimization, synthetic acid solutions of Pbwere employed for calibration. Calibrationwas linearwithin therange 1-40 μg L-1 (correlation coefficient of 0.9995) when the 283.3 analytical line was used. Using optimizedconditions limits of detection (3S) of 0.6 μg L-1 were achieved. The repeatability between injections (Sr%) wasevaluated andwas better than 4.2%. The precision (%RSD) for Pb determination in a single samplewas estimatedby analyzing three strips of the same filter. In all cases the RSD was better than 6.9%. For checking accuracy, analiquot of a Standard ReferenceMaterial (NIST 2709, San Joaquin Soil) was subject to the same sample treatmentand included in the overall analytical process. Thismethodwas successfully applied to the determination of Pb inairborne particulate matter collected in Buenos Aires city.