Microwave extraction as an alternative to ultrasound probe for antimony speciation in airborne particulate matter

An extraction method for Sb(V) and Sb(III) speciation in airborne particulate matter (PM) collected upon quartz filters has been developed, based on microwave extraction at 90 W with an 0.05 mol L− 1 hydroxylammonium chlorhydrate solution. The analysis of the extracts was performed by coupling high performance liquid chromatography (HPLC) with atomic fluorescence spectrometry (AFS). The parameters optimized were the volume of the extractant (5 or 10 mL, depending on the Sb concentration of the samples) and the time of extraction (6 min). The proposed microwave extraction method was compared to an existing one based on the use of ultrasound probe. Both extraction methodologies were applied to Sb spiked blanks (extracting solutions and quartz filters), and PM10 samples containing Sb collected at the city of Córdoba, an urban location of southern Spain. Similar and satisfactory results were obtained for spiked blanks with both methods. However, for PM10 samples quantitative results considering extraction efficiency (> 95%) were obtained only by the proposed method based on microwave extraction, higher than with ultrasound probe extraction (< 70%). Both Sb(V) and Sb(III) were found in the analyzed PM10 samples, Sb(V) being the main Sb species.