Set-up of extraction procedures for ions quantification in aerosol samples

Ions quantification in aerosol samples is commonly achieved by means of Ion Chromatography (IC) after extraction of the analytes from the filter generally using MQ water and operating in an ultra-sound bath. Although this sample preparation system is widely employed in the literature, some important aspects such as ions recovery percentages after the extraction are often not taken into consideration. The aim of this work was to focus on the optimization of the extraction method for different types of filter supports (i.e. PTFE and quartz-fibre filters), which are commonly used for aerosol sampling. For SO4=, NO3- and NH4+ the best recoveries, after a single extraction step, were achieved with PTFE while chlorides recovery was quite low and not reproducible. When quartz is employed and a single extraction step used, in order to give a correct quantification of ions concentration it is generally necessary to apply a correction factor but for chloride quantification three subsequent steps are mandatory. Both techniques and extraction procedure uncertainties have been evaluated and resulted to be within 10%. Limit of detection (LOD) for all the analysed species were determined and it was found that they were within the ranges reported in the literature.